HomeMy WebLinkAboutCT 2019-0006; 2690 ROOSEVELT STREET; GEOTECHNICAL INVESTIGATION; 2019-04-08GEOTECHNICAL INVESTIGATION
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
PREPARED FOR KITCHELL DEVELOPMENT COMPANY DEL MAR, CALIFORNIA
APRIL 8, 2019 PROJECT NO. G2245-52-01
GROCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL MATERIALSO
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159
Project No. G2245-52-01
April 8, 2019
Kitchell Development Company 1555 Camino Del Mar, Suite 307 Del Mar, California 92014
Attention: Mr. Marne Bouillon
Subject: GEOTECHNICAL INVESTIGATION
2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA
Dear Mr. Bouillon:
In accordance with your authorization of our Proposal No. LG-17436, we herein submit the results of
our geotechnical investigation for the subject site. The accompanying report presents the results of our study and conclusions and recommendations pertaining to the geotechnical aspects of the proposed residential development. The site is considered suitable for development provided the recommendations of this report are followed.
Should you have questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Lilian E. Rodriguez RCE 83227 Shawn Foy Weedon GE 2714 John Hoobs CEG 1524
LER:SFW:JH:dmc
(e-mail) Addressee
TABLE OF CONTENTS
1. PURPOSE AND SCOPE ...................................................................................................................... 1
2. SITE AND PROJECT DESCRIPTION ................................................................................................ 1
3. GEOLOGIC SETTING ......................................................................................................................... 2
4. SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 2 4.1 Undocumented Fill (Qudf) ......................................................................................................... 3
4.2 Old Paralic Deposits (Qop) ......................................................................................................... 3 4.3 Santiago Formation (Tsa) ........................................................................................................... 3
5. GROUNDWATER ............................................................................................................................... 3
6. GEOLOGIC HAZARDS ...................................................................................................................... 4 6.1 Faulting and Seismicity .............................................................................................................. 4 6.2 Ground Rupture .......................................................................................................................... 5 6.3 Liquefaction ................................................................................................................................ 6 6.4 Seiches and Tsunamis ................................................................................................................. 6 6.5 Landslides ................................................................................................................................... 6
7. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 7 7.1 General ........................................................................................................................................ 7
7.2 Excavation and Soil Characteristics ........................................................................................... 8 7.3 Seismic Design Criteria .............................................................................................................. 9 7.4 Temporary Excavations ............................................................................................................ 11
7.5 Grading ..................................................................................................................................... 11 7.6 Shallow Foundations ................................................................................................................ 12 7.7 Concrete Slabs-On-Grade ......................................................................................................... 15
7.8 Concrete Flatwork .................................................................................................................... 16 7.9 Retaining Walls ........................................................................................................................ 18 7.10 Lateral Loading ......................................................................................................................... 20 7.11 Preliminary Pavement Recommendations ................................................................................ 20 7.12 Site Drainage and Moisture Protection ..................................................................................... 25 7.13 Grading and Foundation Plan Review ...................................................................................... 26 LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS Figure 1, Vicinity Map
Figure 2, Geologic Map Figure 3, Wall/Column Footing Dimension Detail Figure 4, Retaining Wall Loading Diagram Figure 5, Typical Retaining Wall Drain Detail
TABLE OF CONTENTS (Concluded)
APPENDIX A FIELD INVESTIGATION Figures A-1 – A-5, Logs of Borings
APPENDIX B LABORATORY TESTING
Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results Table B-II, Summary of Laboratory Direct Shear Test Results Table B-III, Summary of Laboratory Expansion Index Test Results Table B-IV, Summary of Laboratory Water-Soluble Sulfate Test Results Table B-V, Summary of Laboratory Unconfined Compressive Strength Test Results Figure B-1, Gradation Curves Figures B-2 – B-3, Consolidation Curves APPENDIX C STORM WATER MANAGEMENT INVESTIGATION APPENDIX D RECOMMENDED GRADING SPECIFICATIONS LIST OF REFERENCES
Project No. G2245-52-01 - 1 - April 8, 2019
GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of our geotechnical investigation for the planned residential
development located at 2690 Roosevelt Street in the City of Carlsbad, California (see Vicinity Map,
Figure 1). The purpose of the geotechnical investigation is to evaluate the surface and subsurface soil
conditions and general site geology, and to identify geotechnical constraints that may affect
development of the property including faulting, liquefaction and seismic shaking based on the 2016
CBC seismic design criteria. In addition, we provided recommendations for remedial grading, shallow
foundations, concrete slab-on-grade, concrete flatwork, preliminary pavement, and retaining walls.
The scope of this investigation also included a review of readily available published and unpublished
geologic literature (see List of References).
The scope of this investigation included performing a site reconnaissance, field exploration,
engineering analyses and preparing this report. We performed our field investigation on February 1,
2018 by advancing 5 small-diameter borings to a maximum depth of approximately 19½ feet below
the existing ground surface. The Geologic Map, Figure 2, presents the approximate locations of the
borings. Appendix A provides a detailed discussion of the field investigation including logs of the
borings. Details of the laboratory tests and a summary of the test results are presented in Appendix B
and on the boring logs in Appendix A. Appendix C presents the results of the storm water
investigation to help evaluate proposed storm water management devices.
Recommendations presented herein are based on analyses of data obtained from our site investigation
and our understanding of proposed site development. References reviewed to prepare this report are
provided in the List of References. If project details vary significantly from those described herein,
Geocon should be contacted to evaluate the necessity for review and possible revision of this report.
2. SITE AND PROJECT DESCRIPTION
The subject site is located north of the intersection of Roosevelt Street and Beech Avenue in a
residential area in the City of Carlsbad, California. The site currently consists of a single-family
residence that has been modified to commercial space. The site is accessed from Roosevelt Street by a
concrete drive to north and a gravel driveway to the south of the structure with parking available to the
east of the building. The property slopes gently to the northwest with elevations ranging from about 41
to 47 feet above Mean Sea Level (MSL). Overhead utility lines exist fronting Roosevelt Street.
We understand proposed development will consist of demolishing the existing structure and
constructing four, 3-story, residential buildings consisting of 10 units with accommodating garages,
driveways, utilities, landscaping and hardscape. The planned ground floor elevations of the buildings
Project No. G2245-52-01 - 2 - April 8, 2019
will range from approximately 42.6 to 44.4 feet MSL. We expect cuts and fills less than approximately
3 feet will be required to achieve planned grades, and we expect the planned structures will be
supported on shallow foundations with a concrete-slab-on-grade.
The site descriptions and proposed development are based on a site reconnaissance, review of
published geologic literature, our field investigation, a review of preliminary architectural and grading
plans, and discussions with you. If development plans differ from those described herein, Geocon
should be contacted for review of the plans and possible revisions to this report.
3. GEOLOGIC SETTING
The site is located in a coastal plain environment within the southern portion of the Peninsular Ranges
Geomorphic Province of southern California. The Peninsular Ranges is a geologic and geomorphic
province that extends from the Imperial Valley to the Pacific Ocean and from the Transverse Ranges
to the north and into Baja California to the south. The coastal plain of San Diego County is underlain
by a thick sequence of relatively undisturbed and non-conformable sedimentary rocks that thicken to
the west and range in age from Upper Cretaceous through the Pleistocene with intermittent deposition.
The sedimentary units are deposited on bedrock, Cretaceous to Jurassic age igneous and metavolcanic
rocks. Geomorphically, the coastal plain is characterized by a series of 21 stair-stepped, marine
terraces which are younger to the west and have been dissected by west flowing rivers that drain the
Peninsular Ranges to the east. The coastal plain is a relatively stable block that is dissected by
relatively few faults consisting of the potentially active La Nacion Fault Zone and the active Rose
Canyon Fault Zone. The Peninsular Ranges Province is also dissected by the Elsinore Fault Zone that
is associated with and sub-parallel to the San Andreas Fault Zone, which is the plate boundary
between the Pacific and North American Plates.
The site is located within the western portion of the coastal plain geologic province roughly 1,000 feet
from Buena Vista Lagoon and 2,000 feet from the Pacific Ocean. The site is located on a near flat
lying marine terrace designated as Pleistocene-age Old Paralic Deposits that deposited soils at a near
shore environment. The Santiago Formation is present below the terrace deposits that was deposited as
a marine sandstone during the Eocene-age. The site has geologically remained unchanged since
deposition of the Old Paralic Deposits.
4. SOIL AND GEOLOGIC CONDITIONS
We encountered one surficial soil (consisting of undocumented fill) and two geologic formations
(consisting of Old Paralic Deposits and the Santiago Formation) during our field investigation. The
occurrence, distribution and description of each unit encountered are shown on the Geologic Map,
Figure 2 and the boring logs in Appendix A. The surficial soils and geologic units are described herein
in order of increasing age.
Project No. G2245-52-01 - 3 - April 8, 2019
4.1 Undocumented Fill (Qudf)
We encountered fill to depths ranging from about 1 to 3 feet from existing grade in the exploratory
borings. The fill is likely associated with the previous grading operations performed during the
original development of the property. The fill is generally composed of loose to medium dense, silty
sand and sandy clay. Based on the laboratory test results, the clayey portion of the fill material at the
location tested possesses a “high” expansion potential (expansion index of 91 to 130). The
undocumented fill is not considered suitable for additional fill or structural loads. Remedial grading of
the undocumented fill will be required as discussed herein.
4.2 Old Paralic Deposits (Qop)
We encountered late to middle Pleistocene-age Old Paralic Deposits underlying the undocumented fill
to depths varying from approximately 14 to 19 feet below existing grades. The Old Paralic Deposits
generally consists of medium dense to very dense, silty to clayey sandstone and stiff to hard, sandy
claystone. The Old Paralic Deposits are considered suitable to support additional loads from fill and
the planned development.
4.3 Santiago Formation (Tsa)
We encountered middle Eocene-age Santiago Formation underlying the Old Paralic Deposits at depths
ranging from 14 to 19 feet (elevations of about 26 to 30 feet MSL). The Santiago Formation
encountered generally consists of very dense, silty to clayey sandstone and very stiff to hard, sandy
claystone. We do not expect Santiago Formation will be encountered during construction unless
subterranean levels or deep underground utilities exceeding approximately 15 feet in depth are
proposed. The Santiago Formation is considered suitable to support additional loads from fill and the
planned development.
5. GROUNDWATER
We encountered perched groundwater in Borings B-1 through B-4 in the Old Paralic Deposits at
depths ranging from approximately 7½ to 11½ feet below the existing ground surface (approximate
elevations ranging from approximately 32½ to 37½ feet MSL). Perched groundwater should be
expected if subterranean levels are proposed and in excavations for deeper utilities. It is not
uncommon for groundwater or seepage conditions to develop where none previously existed.
Groundwater elevations are dependent on seasonal precipitation, irrigation, and land use, among other
factors, and vary as a result. Proper surface drainage will be important to future performance of the
project.
Project No. G2245-52-01 - 4 - April 8, 2019
6. GEOLOGIC HAZARDS
6.1 Faulting and Seismicity
A review of the referenced geologic materials and our knowledge of the general area indicate that the
site is not underlain by active, potentially active or inactive faults. An active fault is defined by the
California Geological Survey (CGS) as a fault showing evidence for activity within the last 11,000 years.
The site is not located within a State of California Earthquake Fault Zone.
According to the computer program EZ-FRISK (Version 7.65), 10 known active faults are located within
a search radius of 50 miles from the property. We used the 2008 USGS fault database that provides
several models and combinations of fault data to evaluate the fault information. Based on this database,
the nearest known active faults are the Newport-Inglewood/Rose Canyon Fault system, located
approximately 5 miles west of the site and is the dominant source of potential ground motion.
Earthquakes that might occur on this fault system or other faults within the southern California and
northern Baja California area are potential generators of significant ground motion at the site. The
estimated deterministic maximum earthquake magnitude and peak ground acceleration for the Newport-
Inglewood Fault are 7.5 and 0.40g, respectively. The estimated deterministic maximum earthquake
magnitude and peak ground acceleration for the Rose Canyon Fault are 6.9 and 0.32g, respectively.
Table 6.1.1 lists the estimated maximum earthquake magnitude and peak ground acceleration for these
and other faults in relationship to the site location. We used acceleration attenuation relationships
developed by Boore-Atkinson (2008) NGA USGS2008, Campbell-Bozorgnia (2008) NGA USGS, and
Chiou-Youngs (2007) NGA USGS2008 acceleration-attenuation relationships in our analysis.
TABLE 6.1.1 DETERMINISTIC SPECTRA SITE PARAMETERS
Fault Name
Approximate Distance from Site (miles)
Maximum Earthquake Magnitude (Mw)
Peak Ground Acceleration
Boore-Atkinson 2008 (g)
Campbell-Bozorgnia 2008 (g)
Chiou-Youngs 2007 (g)
Newport-Inglewood 5 7.5 0.33 0.33 0.40
Rose Canyon 5 6.9 0.27 0.29 0.32
Coronado Bank 21 7.4 0.15 0.11 0.13
Palos Verdes Connected 21 7.7 0.17 0.12 0.15
Elsinore 23 7.9 0.26 0.21 0.29
Palos Verdes 34 7.3 0.10 0.07 0.08
San Joaquin Hills 36 7.1 0.09 0.09 0.08
Earthquake Valley 44 6.8 0.06 0.05 0.04
Chino 47 6.8 0.06 0.05 0.04
San Jacinto 47 7.9 0.10 0.07 0.09
Project No. G2245-52-01 - 5 - April 8, 2019
We used the computer program EZ-FRISK to perform a probabilistic seismic hazard analysis. The
computer program EZ-FRISK operates under the assumption that the occurrence rate of earthquakes on
each mappable Quaternary fault is proportional to the faults slip rate. The program accounts for fault
rupture length as a function of earthquake magnitude, and site acceleration estimates are made using
the earthquake magnitude and distance from the site to the rupture zone. The program also accounts
for uncertainty in each of following: (1) earthquake magnitude, (2) rupture length for a given
magnitude, (3) location of the rupture zone, (4) maximum possible magnitude of a given earthquake,
and (5) acceleration at the site from a given earthquake along each fault. By calculating the expected
accelerations from considered earthquake sources, the program calculates the total average annual
expected number of occurrences of site acceleration greater than a specified value. We utilized
acceleration-attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS 2008,
Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2007) NGA USGS 2008 in our
analysis in the analysis. Table 6.1.2 presents the probabilistic seismic hazard parameters including
acceleration-attenuation relationships and the probability of exceedence.
TABLE 6.1.2
PROBABILISTIC SEISMIC HAZARD PARAMETERS
Probability of Exceedence
Peak Ground Acceleration
Boore-Atkinson 2008 (g) Campbell-Bozorgnia 2008 (g) Chiou-Youngs 2007 (g)
2% in a 50 Year Period 0.45 0.47 0.52
5% in a 50 Year Period 0.33 0.33 0.36
10% in a 50 Year Period 0.24 0.24 0.25
While listing peak accelerations is useful for comparison of potential effects of fault activity in a
region, other considerations are important in seismic design, including the frequency and duration of
motion and the soil conditions underlying the site. Seismic design of the structures should be evaluated
in accordance with the 2016 California Building Code (CBC) or other applicable guidelines.
It is our opinion the site could be subjected to moderate to severe ground shaking in the event of an
earthquake along any of the faults listed on Table 6.1.1 or other faults in the southern California/
northern Baja California region. We do not consider the site to possess a greater risk than that of the
surrounding developments.
6.2 Ground Rupture
Ground surface rupture occurs when movement along a fault is sufficient to cause a gap or rupture
where the upper edge of the fault zone intersects that earth surface. The potential for ground rupture is
considered to be very low due to the absence of active or potentially active faults at the subject site.
Project No. G2245-52-01 - 6 - April 8, 2019
6.3 Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are
cohesionless or silt/clay with low plasticity, groundwater is encountered within 50 feet of the surface,
and soil densities are less than about 70 percent of the maximum dry densities. If the four previous
criteria are met, a seismic event could result in a rapid pore water pressure increase from the
earthquake-generated ground accelerations. Due to the dense to very dense nature and age of the Old
Paralic Deposits and Santiago Formation, liquefaction potential for the site is considered very low.
6.4 Seiches and Tsunamis
Seiches are caused by the movement of an inland body of water due to the movement from seismic
forces. The site is not located near an inland body of water. Therefore, the risk of a seiche from
flooding within the river valley is considered low.
A tsunami is a series of long-period waves generated in the ocean by a sudden displacement of large
volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or offshore
slope failures. The site is located approximately 2,000 feet from the Pacific Ocean and 1,000 feet from
Buena Vista Lagoon at an elevation of at least approximately 40 feet above Mean Sea Level.
Therefore, the risk of tsunamis affecting the site is negligible.
6.5 Landslides
Based on the generally flat topography of the site, it is our opinion that landslides are not present at the
property or at a location that could impact the subject site.
Project No. G2245-52-01 - 7 - April 8, 2019
7. CONCLUSIONS AND RECOMMENDATIONS
7.1 General
7.1.1 From a geotechnical engineering standpoint, it is our opinion that the site is suitable for
construction of the proposed new residential development provided the recommendations
presented herein are implemented in design and construction of the project.
7.1.2 The site is located approximately 5 miles from the nearest active fault. Based on our
background research, it is our opinion active, potentially active, or inactive faults do not
extend across the site. Risks associated with seismic activity consist of the potential for
moderate to strong seismic shaking.
7.1.3 Our field investigation indicates the site is underlain by undocumented fill overlying Old
Paralic Deposits and the Santiago Formation. The thickness of the undocumented fill
encountered at the site during the investigation ranges from approximately 1 to 3 feet. The
undocumented fill is not considered suitable for the support of additional fill and/or
settlement-sensitive building structures in its current state and will require remedial grading.
The Old Paralic Deposits and Santiago Formation are considered suitable for the support of
compacted fill and settlement-sensitive structures.
7.1.4 The planned structures can be supported on a shallow foundation system embedded into
new compacted fill or the Old Paralic Deposits. We expect the shallow foundation system
will be supported in properly compacted fill.
7.1.5 We encountered a variable perched groundwater condition within the Old Paralic Deposits
at depths ranging from approximately 7½ to 11½ feet below the existing ground surface
(approximate elevations ranging from approximately 32½ to 37½ feet MSL) in Borings B-1
through B-4. Perched groundwater and seepage should be expected during construction if
subterranean levels or deep utilities are planned below a depth of about 7 feet. In addition,
saturated soil should be expected at depths as shallow as 3 feet.
7.1.6 Based on our review of the project plans, we opine the planned development can be
constructed in accordance with our recommendations provided herein. We do not expect the
planned development will destabilize or result in settlement of adjacent properties or impact
public right-a-ways.
7.1.7 Proper drainage should be maintained in order to preserve the engineering properties of the
fill in the graded pad areas subsequent to the grading operations.
Project No. G2245-52-01 - 8 - April 8, 2019
7.1.8 Final grading or foundation plans have not been provided for our review. Geocon
Incorporated should review the plans prior to the submittal to regulatory agencies for
approval. Additional analyses may be required once the plans have been provided.
7.2 Excavation and Soil Characteristics
7.2.1 Excavation of the undocumented fill and Old Paralic Deposits should be possible with
moderate to heavy effort using conventional heavy-duty equipment. Excavation of the
Santiago Formation, if encountered, should generally be possible with heavy to very heavy
effort using conventional, heavy-duty equipment during grading and trenching operations.
Some soil may be saturated and require drying before proper placement and compaction.
7.2.2 The soil encountered in the field investigation is considered to be “expansive” (expansion
index [EI] of greater than 20) as defined by 2016 California Building Code (CBC)
Section 1803.5.3. Table 7.2.1 presents soil classifications based on the expansion index. We
expect a majority of the soil encountered possess a “very low” to “high” expansion potential
(EI of 130 or less) in accordance with ASTM D 4829.
TABLE 7.2.1 EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) ASTM D 4829 Expansion Classification 2016 CBC Expansion Classification
0 – 20 Very Low Non-Expansive
21 – 50 Low
Expansive 51 – 90 Medium
91 – 130 High
Greater Than 130 Very High
7.2.3 We performed a laboratory test on sample of the site materials to evaluate the percentage of
water-soluble sulfate content. Appendix B presents results of the laboratory water-soluble
sulfate content test. The test result indicates the on-site materials at the location tested
possesses “S1” sulfate exposure to concrete structures as defined by 2016 CBC
Section 1904 and ACI 318-14 Chapter 19. Table 7.2.2 presents a summary of concrete
requirements set forth by 2016 CBC Section 1904 and ACI 318. The presence of water-
soluble sulfates is not a visually discernible characteristic; therefore, other soil samples from
the site could yield different concentrations. Additionally, over time landscaping activities
(i.e., addition of fertilizers and other soil nutrients) may affect the concentration.
Project No. G2245-52-01 - 9 - April 8, 2019
TABLE 7.2.2 REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING SOLUTIONS
Exposure Class
Water-Soluble Sulfate (SO4) Percent by Weight
Cement Type (ASTM C 150)
Maximum Water to Cement Ratio by Weight1
Minimum Compressive Strength (psi)
S0 SO4<0.10 No Type Restriction n/a 2,500
S1 0.10<SO4<0.20 II 0.50 4,000
S2 0.20<SO4<2.00 V 0.45 4,500
S3 SO4>2.00 V+Pozzolan or Slag 0.45 4,500
1 Maximum water to cement ratio limits do not apply to lightweight concrete
7.2.4 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore,
further evaluation by a corrosion engineer may be performed if improvements susceptible to
corrosion are planned.
7.3 Seismic Design Criteria
7.3.1 We used the Structural Engineers Association of California (SEAOC) and Office of
Statewide Health Planning and Development (OSHPD) web application Seismic Design
Maps (https://seismicmaps.org/) to evaluate site-specific seismic design parameters in
accordance with the 2016 CBC/ASCE 7-10. Table 7.3.1 summarizes site-specific design
criteria obtained from the 2016 California Building Code (CBC; Based on the 2015
International Building Code [IBC] and ASCE 7-10), Chapter 16 Structural Design, Section
1613 Earthquake Loads. The short spectral response uses a period of 0.2 second. The
building structure and improvements as currently proposed should be designed using a Site
Class C in accordance with ASCE 7-10 Section 20.3.1. We evaluated the Site Class based on
the discussion in Section 1613.3.2 of the 2016 CBC and Table 20.3-1 of ASCE 7-10 using
blow count data presented on the boring logs in Appendix A and the unconfined
compressive strength results of the samples collected during the investigation presented in
Appendix B. The values presented in Table 7.3.1 are for the risk-targeted maximum
considered earthquake (MCER).
Project No. G2245-52-01 - 10 - April 8, 2019
TABLE 7.3.1 2016 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2016 CBC Reference
Site Class C Section 1613.3.2
MCER Ground Motion Spectral Response Acceleration – Class B (short), SS 1.153g Figure 1613.3.1(1)
MCER Ground Motion Spectral Response Acceleration – Class B (1 sec), S1 0.442g Figure 1613.3.1(2)
Site Coefficient, FA 1.000 Table 1613.3.3(1)
Site Coefficient, FV 1.358 Table 1613.3.3(2)
Site Class Modified MCER Spectral Response Acceleration (short), SMS 1.153g Section 1613.3.3 (Eqn 16-37)
Site Class Modified MCER Spectral Response Acceleration (1 sec), SM1 0.600g Section 1613.3.3 (Eqn 16-38)
5% Damped Design
Spectral Response Acceleration (short), SDS 0.769g Section 1613.3.4 (Eqn 16-39)
5% Damped Design Spectral Response Acceleration (1 sec), SD1 0.400g Section 1613.3.4 (Eqn 16-40)
7.3.2 Table 7.3.2 presents additional seismic design parameters for projects located in Seismic
Design Categories of D through F in accordance with ASCE 7-10 for the mapped maximum
considered geometric mean (MCEG). The project structural engineer should evaluate the
Risk Category and Seismic Design Category for the planned project.
TABLE 7.3.2 2016 CBC SITE ACCELERATION PARAMETERS
Parameter Value ASCE 7-10 Reference
Site Class C Section 1613.3.2
Mapped MCEG Peak Ground Acceleration, PGA 0.457g Figure 22-7
Site Coefficient, FPGA 1.000 Table 11.8-1
Site Class Modified MCEG Peak Ground Acceleration, PGAM 0.457g Section 11.8.3 (Eqn 11.8-1)
7.3.3 Conformance to the criteria in Tables 7.3.1 and 7.3.2 for seismic design does not constitute
any kind of guarantee or assurance that significant structural damage or ground failure will
not occur if a large earthquake occurs. The primary goal of seismic design is to protect life,
not to avoid all damage, since such design may be economically prohibitive.
Project No. G2245-52-01 - 11 - April 8, 2019
7.4 Temporary Excavations
7.4.1 The recommendations included herein are provided for stable temporary excavations. It is
the responsibility of the contractor to provide a safe excavation during the construction of
the proposed project.
7.4.2 Temporary excavations should be made in conformance with OSHA requirements. The
undocumented fill should be considered a Type C soil, properly compacted fill and
competent Old Paralic Deposits can be considered a Type B soil (Type C soil if seepage or
groundwater is encountered), and competent Santiago Formation (without weak planes) can
be considered a Type A soil (Type B soil if seepage or groundwater is encountered) in
accordance with OSHA requirements. In general, special shoring requirements will not be
necessary if temporary excavations will be less than 4 feet in height. Temporary excavations
greater than 4 feet in height, however, should be sloped back at an appropriate inclination.
These excavations should not be allowed to become saturated or to dry out. Surcharge loads
should not be permitted to a distance equal to the height of the excavation from the top of
the excavation. The top of the excavation should be a minimum of 15 feet from the edge of
existing improvements. Excavations steeper than those recommended or closer than 15 feet
from an existing surface improvement should be shored in accordance with applicable
OSHA codes and regulations.
7.5 Grading
7.5.1 Grading should be performed in accordance with the recommendations provided in this
report, the Recommended Grading Specifications contained in Appendix D and the City of
Carlsbad Grading Ordinance.
7.5.2 Prior to commencing grading, a pre-construction conference should be held at the site with
the owner/developer, city inspector, grading contractor, civil engineer, and geotechnical
engineer in attendance. Special soil handling requirements can be discussed at that time.
7.5.3 Grading of the site should commence with the demolition of existing structures,
improvements, vegetation and deleterious debris from the area to be graded. Deleterious
debris and vegetation should be exported from the site and should not be mixed with the fill.
Existing underground improvements and foundations including old septic systems or
cisterns within the proposed development area should be removed and the resulting
depressions properly backfilled in accordance with the procedures described herein.
7.5.4 The undocumented fill should be removed and replaced with properly compacted fill within
the proposed development area. In addition, the building pad should be excavated such that
Project No. G2245-52-01 - 12 - April 8, 2019
at least 3 feet of compacted fill exists below the planned structure. The undercuts should
extend at least 10 feet outside of the planned building envelope, where possible.
7.5.5 It appears biofiltration basins are planned adjacent to the proposed structures. The removals
for the areas of the structures adjacent to the storm water devices should be extended to at
least 2 feet below the proposed foundations so the structure is supported on compacted fill.
7.5.6 The site should then be brought to final subgrade elevations with fill compacted in layers,
where necessary. In general, soil native to the site is suitable for use as new fill if relatively
free from vegetation, debris and other deleterious material. Layers of fill should be about 6
to 8 inches in loose thickness and no thicker than will allow for adequate bonding and
compaction. Fill, including backfill and scarified ground surfaces, should be compacted to a
dry density of at least 90 percent of the laboratory maximum dry density near to slightly
above optimum moisture content, as determined in accordance with ASTM Test Procedure
D 1557. Fill materials placed below optimum moisture content may require additional
moisture conditioning prior to placing additional fill. The upper 12 inches of subgrade soil
underlying pavement should be compacted to a dry density of at least 95 percent of the
laboratory maximum dry density near to slightly above optimum moisture content shortly
before paving operations.
7.5.7 Import fill soil (if necessary) should consist of granular materials with a “very low” to
“medium” expansion potential (EI of 90 or less) free of deleterious material and stones
larger than 3 inches and should be compacted as recommended herein. Geocon Incorporated
should be notified of the import soil source and should perform laboratory testing of import
soil prior to its arrival at the site to determine its suitability as fill material.
7.6 Shallow Foundations
7.6.1 The proposed structures can be supported on a shallow foundation system bearing in
compacted fill or formation materials. Foundations for the structure should consist of
continuous strip footings and/or isolated spread footings. Continuous footings should be at
least 12 inches wide and extend at least 24 inches below lowest adjacent pad grade. Isolated
spread footings should have a minimum width of 2 feet and should also extend at least
24 inches below lowest adjacent pad grade. Figure 3 presents a wall/column footing
dimension detail.
7.6.2 It appears biofiltration basins are planned adjacent to the proposed structures. The
foundation should be deepened at least 1 foot below the adjacent structures. The foundation
deepening can be removed if the basin devices are designed to incorporate the structural
Project No. G2245-52-01 - 13 - April 8, 2019
load of the planned structures. The project structural engineer should evaluate if the
foundations adjacent to the basins should be designed as retaining walls.
7.6.3 Steel reinforcement for continuous footings should consist of at least four No. 5 steel
reinforcing bars placed horizontally in the footings, two near the top and two near the
bottom. Steel reinforcement for the spread footings should be designed by the project
structural engineer.
7.6.4 The recommendations presented herein are based on soil characteristics only (EI of 130 or
less) and are not intended to replace steel reinforcement required for structural
considerations.
7.6.5 We expect foundations will be founded in properly compacted fill or Old Paralic Deposits.
Foundations may be designed for an allowable soil bearing pressure of 2,000 and 4,000
pounds per square foot (psf) (dead plus live load) for footings founded in compacted fill and
Old Paralic Deposits, respectively. If a bearing value to support the structure within
formational materials is contemplated, then the depth of the footing will likely need to be
extended at least 3 feet below existing grades. This soil bearing pressure may be increased
by 500 psf for each additional foot of foundation width and depth, respectively, up to a
maximum allowable soil pressure of 4,000 and 6,000 psf in compacted fill and Old Paralic
Deposits, respectively. The values presented herein are for dead plus live loads and may be
increased by one-third when considering transient loads due to wind or seismic forces.
7.6.6 Overexcavation of the footings and replacement with slurry can be performed in areas
where the formational materials are not encountered at the bottom of the footing excavations
if the foundations will be extended to the formational materials. Minimum two-sack slurry
can be placed in the excavations for the conventional foundations to the bottom of proposed
footing elevation.
7.6.7 We estimate the total and differential settlements under the imposed allowable loads to be
about 1 inch based on a 6-foot square footing bearing in compacted fill or Old Paralic
Deposits.
7.6.8 As an alternative to the conventional foundation recommendations, consideration should be
given to the use of post-tensioned concrete slab and foundation systems for the support of
the proposed structures. The post-tensioned systems should be designed by a structural
engineer experienced in post-tensioned slab design and design criteria of the Post-
Tensioning Institute (PTI) DC10.5 as required by the 2016 California Building Code (CBC
Section 1808.6.2). Although this procedure was developed for expansive soil conditions, we
Project No. G2245-52-01 - 14 - April 8, 2019
understand it can also be used to reduce the potential for foundation distress due to
differential fill settlement. The post-tensioned design should incorporate the geotechnical
parameters presented on Table 7.6. The parameters presented in Table 7.6 are based on the
guidelines presented in the PTI, DC10.5 design manual.
TABLE 7.6 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PTI) DC10.5 Design Parameters Value
Thornthwaite Index -20
Equilibrium Suction 3.9
Edge Lift Moisture Variation Distance, eM (feet) 4.9
Edge Lift, yM (inches) 1.58
Center Lift Moisture Variation Distance, eM (feet) 9.0
Center Lift, yM (inches) 0.66
7.6.9 If the structural engineer proposes a post-tensioned foundation design method other than the
PTI DC10.5:
• The criteria presented in Table 7.6 are still applicable.
• Interior stiffener beams should be used.
• The width of the perimeter foundations should be at least 12 inches.
• The perimeter footing embedment depths should be at least 24 inches. The embedment depths should be measured from the lowest adjacent pad grade.
7.6.10 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift,
regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the
perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI
design procedures primarily address the potential center lift of slabs but, because of the
placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after
tensioning reduces the ability of the system to mitigate edge lift. The structural engineer
should design the foundation system to reduce the potential of edge lift occurring for the
proposed structures.
7.6.11 The foundations for the post-tensioned slabs should be embedded in accordance with the
recommendations of the structural engineer. If a post-tensioned mat foundation system is
planned, the slab should possess a thickened edge with a minimum width of 12 inches and
extend below the clean sand or crushed rock layer.
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7.6.12 During the construction of the post-tension foundation system, the concrete should be
placed monolithically. Under no circumstances should cold joints form between the
footings/grade beams and the slab during the construction of the post-tension foundation
system.
7.6.13 We should observe the foundation excavations prior to the placement of reinforcing steel
and concrete to check that the exposed soil conditions are similar to those expected and that
they have been extended to the appropriate bearing strata. If unexpected soil conditions are
encountered, foundation modifications may be required.
7.6.14 Special subgrade presaturation is not deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soil should be moisturized to maintain a moist
condition as would be expected in any such concrete placement.
7.6.15 Geocon Incorporated should be consulted to provide additional design parameters as
required by the structural engineer.
7.7 Concrete Slabs-On-Grade
7.7.1 Concrete floor slabs should possess a thickness of at least 5 inches and reinforced with a
minimum of No. 4 steel reinforcing bars at 18 inches on center in both horizontal directions.
The structural engineer should design the steel required for the planned loading conditions.
7.7.2 Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture-
sensitive materials should be underlain by a vapor retarder. The vapor retarder design should
be consistent with the guidelines presented in the American Concrete Institute’s (ACI)
Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-
06). In addition, the membrane should be installed in accordance with manufacturer’s
recommendations and ASTM requirements and installed in a manner that prevents puncture.
The vapor retarder used should be specified by the project architect or developer based on
the type of floor covering that will be installed and if the structure will possess a humidity
controlled environment.
7.7.3 The bedding sand thickness should be determined by the project foundation engineer,
architect, and/or developer. It is common to have 3 to 4 inches of sand in the southern
California region. However, we should be contacted to provide recommendations if the
bedding sand is thicker than 6 inches. The foundation design engineer should provide
appropriate concrete mix design criteria and curing measures to assure proper curing of the
slab by reducing the potential for rapid moisture loss and subsequent cracking and/or slab
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curl. We suggest that the foundation design engineer present the concrete mix design and
proper curing methods on the foundation plans. It is critical that the foundation contractor
understands and follows the recommendations presented on the foundation plans.
7.7.4 Concrete slabs should be provided with adequate construction joints and/or expansion joints
to control unsightly shrinkage cracking. The design of joints should consider criteria of the
American Concrete Institute when establishing crack-control spacing. Additional steel
reinforcing, concrete admixtures and/or closer crack control joint spacing should be
considered where concrete-exposed concrete finished floors are planned.
7.7.5 Consideration should be given to connecting patio slabs, which exceed 5 feet in width, to
the building foundation to reduce the potential for future separation to occur.
7.7.6 The foundation and concrete slab-on-grade recommendations are based on soil support
characteristics only. The project structural engineer should evaluate the structural
requirements of the concrete slabs for supporting expected loads.
7.7.7 The recommendations of this report are intended to reduce the potential for cracking of slabs
due to expansive soil (if present), differential settlement of existing soil or soil with varying
thicknesses. However, even with the incorporation of the recommendations presented
herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still
exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete
shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may
be reduced and/or controlled by limiting the slump of the concrete, proper concrete
placement and curing, and by the placement of crack control joints at periodic intervals, in
particular, where re-entrant slab corners occur.
7.8 Concrete Flatwork
7.8.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the recommendations herein. Slab panels should be a minimum of 4 inches
thick and, when in excess of 8 feet square, should be reinforced with 4 x 4 – W4.0/W4.0
(4 x 4 – 4/4) welded wire mesh or No. 4 reinforcing bars spaced 18 inches on center in each
direction to reduce the potential for cracking. In addition, concrete flatwork should be
provided with crack control joints to reduce and/or control shrinkage cracking. Crack
control spacing should be determined by the project structural engineer based upon the slab
thickness and intended usage. Criteria of the American Concrete Institute (ACI) should be
taken into consideration when establishing crack control spacing. Subgrade soil for exterior
slabs not subjected to vehicle loads should be compacted in accordance with criteria
Project No. G2245-52-01 - 17 - April 8, 2019
presented in the grading section prior to concrete placement. Subgrade soil should be
compacted to a dry density of at least 90 percent of the laboratory maximum dry density
near to slightly above optimum moisture content in accordance with ASTM D 1557 prior to
placing concrete.
7.8.2 Even with the incorporation of the recommendations within this report, the exterior concrete
flatwork has a likelihood of experiencing some movement due to swelling or settlement;
therefore, the steel reinforcement should overlap continuously in flatwork to reduce the
potential for vertical offsets within flatwork. Additionally, flatwork should be structurally
connected to the curbs, where possible, to reduce the potential for offsets between the curbs
and the flatwork. It is generally not economical to mitigate liquefaction for flatwork.
Therefore, some repairs to flatwork will likely be required following a liquefaction event.
7.8.3 Where exterior flatwork abuts structures at entrant or exit points, the exterior slab should be
dowelled into the structure’s foundation stemwall. This recommendation is intended to
reduce the potential for differential elevations that could result from differential settlement
or minor heave of the flatwork. Dowelling details should be designed by the project
structural engineer.
7.8.4 The recommendations presented herein are intended to reduce the potential for cracking as a
result of differential movement. However, even with the incorporation of the
recommendations presented herein, concrete will still crack. The occurrence of concrete
shrinkage cracks is independent of the soil supporting characteristics. Their occurrence may
be reduced and/or controlled by limiting the slump of the concrete, the use of crack control
joints and proper concrete placement and curing. Crack control joints should be spaced at
intervals no greater than 12 feet. Literature provided by the Portland Concrete Association
(PCA) and American Concrete Institute (ACI) present recommendations for proper concrete
mix, construction, and curing practices, and should be incorporated into project construction.
7.8.5 We understand some of the flatwork may consist of permeable pavement/pavers. We
recommend a drain be installed below permeable flatwork and connected at an appropriate
outlet. If the drain is not installed, water from other sources (e.g. rooftops and landscaping)
should not be directed to the flatwork such that the only water experienced is from rain. The
pervious flatwork should not be installed within 5 feet of the proposed structures, where
possible, or a liner should be installed with an appropriate drainage system.
Project No. G2245-52-01 - 18 - April 8, 2019
7.9 Retaining Walls
7.9.1 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid density of
40 pounds per cubic foot (pcf). Where the backfill will be inclined at 2:1 (horizontal to
vertical), we recommend an active soil pressure of 55 pcf. Soil with an expansion index (EI)
of greater than 90 should not be used as backfill material behind retaining walls.
7.9.2 Retaining walls should be designed to ensure stability against overturning sliding, excessive
foundation pressure. Where a keyway is extended below the wall base with the intent to
engage passive pressure and enhance sliding stability, it is not necessary to consider active
pressure on the keyway.
7.9.3 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals
the height of the retaining portion of the wall) at the top of the wall. Where walls are
restrained from movement at the top (at-rest condition), an additional uniform pressure of
7H psf should be added to the active soil pressure for walls 8 feet or less. For walls greater
than 8 feet tall, an additional uniform pressure of 13H psf should be applied to the wall
starting at 8 feet from the top of the wall. For retaining walls subject to vehicular loads
within a horizontal distance equal to two-thirds the wall height, a surcharge equivalent to
2 feet of fill soil should be added.
7.9.4 The structural engineer should determine the Seismic Design Category for the project in
accordance with Section 1613.3.5 of the 2016 CBC or Section 11.6 of ASCE 7-10. For
structures assigned to Seismic Design Category of D, E, or F, retaining walls that support
more than 6 feet of backfill should be designed with seismic lateral pressure in accordance
with Section 1803.5.12 of the 2016 CBC. The seismic load is dependent on the retained
height where H is the height of the wall, in feet, and the calculated loads result in pounds per
square foot (psf) exerted at the base of the wall and zero at the top of the wall. A seismic
load of 17H should be used for design. We used the peak ground acceleration adjusted for
Site Class effects, PGAM, of 0.457g calculated from ASCE 7-10 Section 11.8.3 and applied
a pseudo-static coefficient of 0.3. Figure 4 presents a retaining wall loading diagram.
7.9.5 The retaining walls may be designed using either the active and restrained (at-rest) loading
condition or the active and seismic loading condition as suggested by the structural
engineer. Typically, it appears the design of the restrained condition for retaining wall
loading may be adequate for the seismic design of the retaining walls. However, the active
earth pressure combined with the seismic design load should be reviewed and also
considered in the design of the retaining walls.
Project No. G2245-52-01 - 19 - April 8, 2019
7.9.6 Drainage openings through the base of the wall (weep holes) should not be used where the
seepage could be a nuisance or otherwise adversely affect the property adjacent to the base
of the wall. The recommendations herein assume a properly compacted granular (EI of 90 or
less) free-draining backfill material with no hydrostatic forces or imposed surcharge load.
Figure 5 presents a typical retaining wall drainage detail. If conditions different than those
described are expected, or if specific drainage details are desired, Geocon Incorporated
should be contacted for additional recommendations.
7.9.7 In general, wall foundations having a minimum depth and width of 1 foot may be designed
for an allowable soil bearing pressure of 2,000 psf. The allowable soil bearing pressure may
be increased by an additional 300 psf for each additional foot of depth and width, to a
maximum allowable bearing capacity of 3,000 psf. The proximity of the foundation to the
top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore,
retaining wall foundations should be deepened such that the bottom outside edge of the
footing is at least 7 feet horizontally from the face of the slope.
7.9.8 The recommendations presented herein are generally applicable to the design of rigid
concrete or masonry retaining walls. In the event that other types of walls (such as
mechanically stabilized earth [MSE] walls, soil nail walls, or soldier pile walls) are planned,
Geocon Incorporated should be consulted for additional recommendations.
7.9.9 Unrestrained walls will move laterally when backfilled and loading is applied. The amount
of lateral deflection is dependent on the wall height, the type of soil used for backfill, and
loads acting on the wall. The retaining walls and improvements above the retaining walls
should be designed to incorporate an appropriate amount of lateral deflection as determined
by the structural engineer.
7.9.10 Soil contemplated for use as retaining wall backfill, including import materials, should be
identified in the field prior to backfill. At that time, Geocon Incorporated should obtain
samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures
may be necessary if the backfill soil does not meet the required expansion index or shear
strength. City or regional standard wall designs, if used, are based on a specific active lateral
earth pressure and/or soil friction angle. In this regard, on-site soil to be used as backfill may
or may not meet the values for standard wall designs. Geocon Incorporated should be
consulted to assess the suitability of the on-site soil for use as wall backfill if standard wall
designs will be used.
Project No. G2245-52-01 - 20 - April 8, 2019
7.10 Lateral Loading
7.10.1 To resist lateral loads, a passive pressure exerted by an equivalent fluid density of
300 pounds per cubic foot (pcf) should be used for the design of footings or shear keys. The
allowable passive pressure assumes a horizontal surface extending at least 5 feet, or three
times the surface generating the passive pressure, whichever is greater. The upper 12 inches
of material in areas not protected by floor slabs or pavement should not be included in
design for passive resistance.
7.10.2 If friction is to be used to resist lateral loads, an allowable coefficient of friction between
soil and concrete of 0.3 should be used for design. The friction coefficient may be reduced
depending on the vapor barrier or waterproofing material used for construction in
accordance with the manufacturer’s recommendations (normally about 0.2 to 0.25).
7.10.3 The passive and frictional resistant loads can be combined for design purposes. The lateral
passive pressures may be increased by one-third when considering transient loads due to
wind or seismic forces.
7.11 Preliminary Pavement Recommendations
7.11.1 We calculated the flexible pavement sections in general conformance with the Caltrans
Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) using an
estimated Traffic Index (TI) of 5.0, 5.5, 6.0, and 7.0 for parking stalls, driveways, medium
truck traffic areas, and heavy truck and fire truck traffic areas, respectively. The project civil
engineer and owner should review the pavement designations to determine appropriate
locations for pavement thickness. The final pavement sections for the pavement should be
based on the R-Value of the subgrade soil encountered at final subgrade elevation. We have
assumed an R-Value of 5 and 78 for the subgrade soil and base materials, respectively, for
the purposes of this preliminary analysis. Table 7.11.1 presents the preliminary flexible
pavement sections.
Project No. G2245-52-01 - 21 - April 8, 2019
TABLE 7.11.1 PRELIMINARY FLEXIBLE PAVEMENT SECTION
Location Assumed Traffic Index
Assumed Subgrade R-Value
Asphalt Concrete (inches)
Class 2 Aggregate Base (inches)
Parking stalls for automobiles and light-duty vehicles 5.0 5 3 10
Driveways for automobiles
and light-duty vehicles 5.5 5 3 12
Medium truck traffic areas 6.0 5 3.5 13
Driveways for heavy truck and fire truck traffic 7.0 5 4 16
7.11.2 Prior to placing base materials, the upper 12 inches of the subgrade soil should be scarified,
moisture conditioned as necessary and recompacted to a dry density of at least 95 percent of
the laboratory maximum dry density near to slightly above optimum moisture content as
determined by ASTM D 1557. Similarly, the base material should be compacted to a dry
density of at least 95 percent of the laboratory maximum dry density near to slightly above
optimum moisture content. Asphalt concrete should be compacted to a density of at least 95
percent of the laboratory Hveem density in accordance with ASTM D 2726.
7.11.3 Base materials should conform to Section 26-1.028 of the Standard Specifications for The
State of California Department of Transportation (Caltrans) with a ¾-inch maximum size
aggregate. The asphalt concrete should conform to Section 203-6 of the Standard
Specifications for Public Works Construction (Greenbook).
7.11.4 The base thickness can be reduced if a reinforcement geogrid is used during the installation
of the pavement. Geocon should be contact for additional recommendations, if required.
7.11.5 A rigid Portland cement concrete (PCC) pavement section should be placed in driveway
entrance aprons and trash bin loading areas. The concrete pad for trash truck areas should be
large enough such that the truck wheels will be positioned on the concrete during loading.
We calculated the rigid pavement section in general conformance with the procedure
recommended by the American Concrete Institute report ACI 330R-08 Guide for Design
and Construction of Concrete Parking Lots using the parameters presented in Table 7.11.2.
Project No. G2245-52-01 - 22 - April 8, 2019
TABLE 7.11.2 RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value
Modulus of subgrade reaction, k 50 pci
Modulus of rupture for concrete, MR 500 psi
Traffic Category, TC A and C
Average daily truck traffic, ADTT 10 and 100
7.11.6 Based on the criteria presented herein, the PCC pavement sections should have a minimum
thickness as presented in Table 7.11.3.
TABLE 7.11.3 RIGID PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Automobile Parking Stalls (TC=A) 6.0
Heavy Truck and Fire Lane Areas (TC=C) 7.5
7.11.7 The PCC pavement should be placed over subgrade soil that is compacted to a dry density
of at least 95 percent of the laboratory maximum dry density near to slightly above optimum
moisture content. This pavement section is based on a minimum concrete compressive
strength of approximately 3,000 psi (pounds per square inch).
7.11.8 A thickened edge or integral curb should be constructed on the outside of concrete slabs
subjected to wheel loads. The thickened edge should be 1.2 times the slab thickness or a
minimum thickness of 2 inches, whichever results in a thicker edge, and taper back to the
recommended slab thickness 4 feet behind the face of the slab (e.g., 6-inch and 7.5-inch-
thick slabs would have an 8- and 9.5-inch-thick edge, respectively). Reinforcing steel will
not be necessary within the concrete for geotechnical purposes with the possible exception
of dowels at construction joints as discussed herein.
7.11.9 To control the location and spread of concrete shrinkage cracks, crack-control joints
(weakened plane joints) should be included in the design of the concrete pavement slab.
Crack-control joints should not exceed 30 times the slab thickness with a maximum spacing
of 15 feet for the 6.0-inch and thicker slabs and should be sealed with an appropriate sealant
to prevent the migration of water through the control joint to the subgrade materials. The
depth of the crack-control joints should be determined by the referenced ACI report. The
depth of the crack-control joints should be at least ¼ of the slab thickness when using a
Project No. G2245-52-01 - 23 - April 8, 2019
conventional saw, or at least 1 inch when using early-entry saws on slabs 9 inches or less in
thickness, as determined by the referenced ACI report discussed in the pavement section
herein. Cuts at least ¼ inch wide are required for sealed joints, and a ⅜ inch wide cut is
commonly recommended. A narrow joint width of 1/10- to 1/8-inch wide is common for
unsealed joints.
7.11.10 To provide load transfer between adjacent pavement slab sections, a butt-type construction
joint should be constructed. The butt-type joint should be thickened by at least 20 percent at
the edge and taper back at least 4 feet from the face of the slab. As an alternative to the butt-
type construction joint, dowelling can be used between construction joints for pavements of
7 inches or thicker. As discussed in the referenced ACI guide, dowels should consist of
smooth, 1-inch-diameter reinforcing steel 14 inches long embedded a minimum of 6 inches
into the slab on either side of the construction joint. Dowels should be located at the
midpoint of the slab, spaced at 12 inches on center and lubricated to allow joint movement
while still transferring loads. In addition, tie bars should be installed at the as recommended
in Section 3.8.3 of the referenced ACI guide. The structural engineer should provide other
alternative recommendations for load transfer.
7.11.11 Concrete curb/gutter should be placed on soil subgrade compacted to a dry density of at
least 90 percent of the laboratory maximum dry density near to slightly above optimum
moisture content. Cross-gutters should be placed on subgrade soil compacted to a dry
density of at least 95 percent of the laboratory maximum dry density near to slightly above
optimum moisture content. Base materials should not be placed below the curb/gutter, cross-
gutters, or sidewalk so water is not able to migrate from the adjacent parkways to the
pavement sections. Where flatwork is located directly adjacent to the curb/gutter, the
concrete flatwork should be structurally connected to the curbs to help reduce the potential
for offsets between the curbs and the flatwork.
7.12 Permeable Interlocking Paver Recommendations
7.12.1 We understand that the use of permeable/pervious pavement is being considered from a
storm water management perspective. The use of permeable/pervious pavement allows
potential surface run-off to be stored on-site and percolated into the underlying subgrade
soil; however, the existing soil conditions are not conducive to water infiltration and
relatively high infiltration rates should not be expected.
7.12.2 We calculated the paver pavement sections in general conformance with the Caltrans
Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) and the
Interlocking Concrete Pavement Institute (ICPI) Tech Spec Number 18. We calculated the
section based on an assumed minimum R-Value of 5 and 78 for the subgrade soil and
Project No. G2245-52-01 - 24 - April 8, 2019
permeable base/stone materials, respectively. We used an equivalent asphalt concrete
section equal to the thickness of the pavers of approximately 3 inches in accordance with
Interlocking Concrete Pavement Institute (ICPI) Tech Spec Number 4. In addition, the
pavers should be installed in a pattern appropriate for vehicular traffic. The vehicular pavers
should possess a minimum thickness of 3⅛ inches and overlie 1 to 1½ inches of bedding
sand or ASTM No. 8 stone. Table 7.12.1 presents the recommended permeable paver
pavement section.
TABLE 7.12.1 PERMEABLE PAVER PAVEMENT SECTION
Location Traffic Index (TI)
Minimum Base and Stone Reservoir Material R-Value
Estimated Paver Thickness (inches)
Option 1 Option 2
Estimated Bedding Coarse Thickness (inches)
Permeable Class 2 Base Thickness (Inches)
ASTM C 33 Aggregate
Parking stalls for automobiles and light-duty vehicles
5.0 78 3⅛ 1 to 1½ 10
2” #8 /
4” #57 / 7” #2
Driveways for
automobiles and light-duty vehicles
5.5 78 3⅛ 1 to 1½ 12
2” #8 / 4” #57 / 9” #2
Medium truck traffic areas 6.0 78 3⅛ 1 to 1½ 14
2” #8 / 4” #57 / 11” #2
Driveways for
heavy truck traffic 7.0 78 3⅛ 1 to 1½ 18
2” #8 /
4” #57 / 16” #2
7.12.3 The permeable base/aggregate sections can be thickened to increase the water capacity as
required by the project civil engineer. Prior to placing stone materials, the subgrade soil
should be scarified, moisture conditioned as necessary, and recompacted to a dry density of
at least 95 percent of the laboratory maximum dry density near to slightly above optimum
moisture content as determined by ASTM D 1557. The depth of compaction should be at
least 12 inches. Similarly, the base materials should be compacted to a dry density of at least
95 percent of the laboratory maximum dry density near to slightly above optimum moisture
content. Some compactive effort should be applied to the aggregate section, if installed.
7.12.4 The pavers should be installed and maintained in accordance with the manufacturer’s
recommendations. The future owners should be made aware and responsible for the
Project No. G2245-52-01 - 25 - April 8, 2019
maintenance program. In addition, pavers tend to shift vertically and horizontally during the
life of the pavement and should be expected. The pavers normally require a concrete border
to prevent lateral movement from traffic. The concrete border surrounding the pavers should
be embedded at least 6 inches into the subgrade to reduce the potential for water migration
to the adjacent landscape areas and pavement areas. The pavers should be placed tightly
adjacent to each other and the spacing between the paver units should be filled with
appropriate filler.
7.12.5 In areas where permeable/pervious pavement is planned, the subgrade materials should be
graded to provide positive drainage (at least 1 percent) into a subdrain and controlled
drainage device. The subdrain should be placed at the bottom of the pavement section along
the low point of the length of the pavement to reduce the potential for water to build up
within the paving section. The proposed pervious pavement is planned between buildings
and the subdrain should be located in the center of the pavement area, approximately
equidistant from the existing buildings. The subdrain should be connected to an approved
drainage device. The drain should consist of a 3-inch diameter perforated Schedule 40, PVC
pipe and placed at the bottom of the base or aggregate materials. Water should not be
allowed to infiltrate within 5 feet of the proposed structures.
7.12.6 Impermeable liners should be installed along the sides of the pavement section to prevent
water migration toward the buildings. The liner should consist of a high-density
polyethylene (HDPE) or equivalent with a minimum thickness of 15 mil and strong enough
to prevent puncture. The liner should be sealed at the connections in accordance with
manufacturer recommendations and should be properly waterproofed at the drain
connection. The side liner would not be required where the concrete cutoff wall is installed
below the proposed aggregate as discussed herein.
7.13 Site Drainage and Moisture Protection
7.13.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2016 CBC 1804.4 or other applicable
standards. In addition, surface drainage should be directed away from the top of slopes into
swales or other controlled drainage devices. Roof and pavement drainage should be directed
into conduits that carry runoff away from the proposed structure.
7.13.2 In the case of basement walls or building walls retaining landscaping areas, a water-proofing
system should be used on the wall and joints, and a Miradrain drainage panel (or similar)
Project No. G2245-52-01 - 26 - April 8, 2019
should be placed over the waterproofing. The project architect or civil engineer should
provide detailed specifications on the plans for all waterproofing and drainage.
7.13.3 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water is allowed to infiltrate the soil for prolonged periods of time.
7.13.4 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement's subgrade and base course. Area drains
to collect excess irrigation water and transmit it to drainage structures or impervious above-
grade planter boxes can be used. In addition, where landscaping is planned adjacent to the
pavement, construction of a cutoff wall along the edge of the pavement that extends at least
6 inches below the bottom of the base material should be considered.
7.13.5 We understand storm water management devices are planned for the proposed development
and biofiltration basins are planned adjacent to the proposed structures. Appendix D
presents recommendations regarding storm water management.
7.13.6 Liners and subdrains should be incorporated into the design and construction of the planned
storm water devices. The liners should be installed on the sides and bottoms of the planned
basins and should be impermeable (e.g. High-density polyethylene, HDPE, with a thickness
of about 40 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration. The
subdrains should be perforated within the liner area, installed at the base and above the liner,
be at least 3 inches in diameter and consist of Schedule 40 PVC pipe. The subdrains outside
of the liner should consist of solid pipe. The penetration of the liners at the subdrains should
be properly waterproofed. The subdrains should be connected to a proper outlet. The
devices should also be installed in accordance with the manufacturer’s recommendations.
7.14 Grading and Foundation Plan Review
7.14.1 Geocon Incorporated should review the project grading and foundation plans prior to final
design submittal to check if additional analyses and/or recommendations are required.
Project No. G2245-52-01 April 8, 2018
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
2. The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during construction,
or if the proposed construction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or corrosive materials was not part of the
scope of services provided by Geocon Incorporated.
3. This report is issued with the understanding that it is the responsibility of the owner or his
representative to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors carry out
such recommendations in the field.
4. The findings of this report are valid as of the present date. However, changes in the conditions
of a property can occur with the passage of time, whether they be due to natural processes or
the works of man on this or adjacent properties. In addition, changes in applicable or
appropriate standards may occur, whether they result from legislation or the broadening of
knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by
changes outside our control. Therefore, this report is subject to review and should not be relied
upon after a period of three years.
SITESITE
NO SCALE
FIG. 1
THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH,
SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS
NOT INTENDED FOR CLIENT'S USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT
SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT
OF SUCH USE OR RELIANCE BY CLIENT.
VICINITY MAP
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2245 - 52 - 01LR / RA
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/05/2019 2:21PM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\DETAILS\G2245-52-01 VicinityMap.dwg
DATE 04 - 08 - 2019
R
O
O
S
E
V
E
L
T
S
T
R
E
E
T
APPROX. LIMITS
OF PROJECT
B-4 B-2
B-3
B-5
B-1
P-1
P-2
Qudf/
Qudf/
PROPOSED BUILDING PROPOSED BUILDING
PROPOSED BUILDINGPROPOSED BUILDING
GEOLOGIC MAP 2
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159PROJECT NO. G2245 - 52 - 01
DATE 04 - 08 - 2019FIGURE
GEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/05/2019 2:21PM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\SHEETS\G2245-52-01 GeologicMap.dwg
GEOCON LEGEND
........UNDOCUMENTED FILL
........APPROX. LOCATION OF BORING
Qudf
B-5
P-2 ........APPROX. LOCATION OF INFILTRATION TEST
........OLD PARALIC DEPOSITS (Dotted Where Buried)Qop
CONCRETE SLAB
FO
O
T
I
N
G
*
DE
P
T
H
FOOTING WIDTH*
SAND AND VAPOR
RETARDER IN
ACCORDANCE WITH ACI
FOOTING*
WIDTH
CONCRETE SLAB
PAD GRADE
FO
O
T
I
N
G
*
DE
P
T
H
SAND AND VAPOR
RETARDER IN
ACCORDANCE WITH ACI
FIG. 3
WALL / COLUMN FOOTING DIMENSION DETAIL
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2245 - 52 - 01LR / RA
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/05/2019 2:22PM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\DETAILS\Wall-Column Footing Dimension Detail (COLFOOT2).dwg
DATE 04 - 08 - 2019
*....SEE REPORT FOR FOUNDATION WIDTH AND DEPTH RECOMMENDATION
H (Feet)
RETAINING
WALL
A psf
13H psf
17H psf
ACTIVE
PRESSURE
AT-REST/
RESTRAINED
(IF REQUIRED)
SEISMIC
(IF REQUIRED)
FOOTING
SLAB
H>8'
IF PRESENT
7HH ≤ 8'
RETAINING WALL LOADING DIAGRAM
FIG. 4
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2245 - 52 - 01LR / RA
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/05/2019 2:22PM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\DETAILS\Retaining Wall Loading Diagram (RWLD-NoGroundwater).dwg
DATE 04 - 08 - 2019
EXPANSION
INDEX, EI
EI ≤ 50
LEVEL
BACKFILL
35
2:1 SLOPING
BACKFILL
50
EI ≤ 90 40 55
ACTIVE PRESSURE, A (psf)
NOTES:
1..... A SURCHARGE OF 2 FEET OF SOIL (250 PSF VERTICAL LOAD) SHOULD BE ADDED TO THE
DESIGN OF THE WALL WHERE TRAFFIC LOADS ARE WITHIN A HORIZONTAL DISTANCE EQUAL
TO 23 THE WALL HEIGHT. OTHER SURCHARGES SHOULD BE APPLIED, AS APPLICABLE.
2..... EXPANSION INDEX GREATER THAN 50/90 SHOULD NOT BE USED FOR WALL BACKFILL PER
REPORT.
3..... RETAINING WALLS SHOULD BE PROPERLY DRAINED AND WATER PROOFED.
4..... THE PROJECT STRUCTURAL ENGINEER SHOULD EVALUATE THE WALLS LOADING
COMBINATIONS.
PROPERLY
COMPACTED
BACKFILL
CONCRETE
BROWDITCH
2/3 H
PROPOSED
RETAINING WALL
GROUND SURFACE
1"
FOOTING 4" DIA. PERFORATED SCHEDULE
40 PVC PIPE EXTENDED TO
APPROVED OUTLET
MIRAFI 140N FILTER FABRIC
(OR EQUIVALENT)
1" MAX. AGGREGATE
OPEN GRADED
GROUND SURFACE
TEMPORARY BACKCUT
PER OSHA
12"
WATER PROOFING
PER ARCHITECT
FOOTING
PROPOSED
GRADE
4" DIA. SCHEDULE 40
PERFORATED PVC PIPE
OR TOTAL DRAIN
EXTENDED TO
APPROVED OUTLET
DRAINAGE PANEL
(MIRADRAIN 6000
OR EQUIVALENT)
RETAINING
WALL
3/4" CRUSHED ROCK
(1 CU.FT./FT.)
NOTE :
DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET
OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING
CONCRETE
BROWDITCH
WATER PROOFING
PER ARCHITECT
GROUND SURFACE
12"
2/3 H 2/3 H
FOOTING
PROPOSED
GRADE
RETAINING
WALL
CONCRETE
BROWDITCH
WATER PROOFING
PER ARCHITECT
GROUND SURFACE
FILTER FABRIC
ENVELOPE
MIRAFI 140N OR
EQUIVALENT
4" DIA. SCHEDULE 40
PERFORATED PVC PIPE
OR TOTAL DRAIN
EXTENDED TO
APPROVED OUTLET
DRAINAGE PANEL
(MIRADRAIN 6000
OR EQUIVALENT)
FIG. 5
TYPICAL RETAINING WALL DRAIN DETAIL
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2245 - 52 - 01LR / RA
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/05/2019 2:22PM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\DETAILS\Typical Retaining Wall Drainage Detail (RWDD7A).dwg
DATE 04 - 08 - 2019
APPENDIX A
Project No. G2245-52-01 April 8, 2018
APPENDIX A
FIELD INVESTIGATION
Fieldwork for our investigation included a subsurface exploration and soil sampling. The Geologic
Map, Figure 2 presents the locations of the exploratory borings. Boring logs and an explanation of the
geologic units encountered are presented in figures following the text in this appendix. We located the
borings in the field using a measuring tape and existing reference points. Therefore, actual boring
locations may deviate slightly. We performed a field investigation on February 1, 2018 that consisted
of drilling 5 exploratory borings to a maximum depth of approximately 19½ feet below existing grade
with an Ingersoll Rand A-300 drill rig equipped with 8-inch-diameter hollow-stem auger with Scott’s
Drilling Company. We obtained bulk and ring samples from the exploratory borings for laboratory
testing.
We obtained samples during our boring excavations using a California split-spoon sampler. The
sampler is composed of steel and is driven to obtain the soil samples. The California sampler has an
inside diameter of 2.5 inches and an outside diameter of 2.875 inches. Up to 18 rings are placed inside
the sampler that is 2.4 inches in diameter and 1 inch in height. Ring samples at appropriate intervals
were retained in moisture-tight containers and transported to the laboratory for testing. We also
retained bulk samples from the borings for laboratory testing. The type of sample is noted on the
exploratory boring logs.
The samplers were driven 12 using the California sampler into the bottom of the excavations with the
use of a Cathead hammer and the use of A rods. The sampler is connected to the A rods and driven
into the bottom of the excavation using a 140-pound hammer with a 30-inch drop. Blow counts are
recorded for every 6 inches the sampler is driven. The penetration resistances shown on the boring
logs are shown in terms of blows per foot. The values indicated on the boring logs are the sum of the
last 12 inches of the sampler if driven 18 inches. If the sampler was not driven for 18 inches, an
approximate value is calculated in term of blows per foot or the final 6-inch interval is reported. These
values are not to be taken as N-values, adjustments have not been applied. We estimated elevations
shown on the boring logs from a topographic map.
We visually examined the soil conditions encountered within the borings, classified, and logged in
general accordance with the Unified Soil Classification System (USCS). Logs of the borings are
presented on Figures A-1 through A-5. The logs depict the general soil and geologic conditions
encountered and the depth at which we obtained the samples.
UNDOCUMENTED FILL (Qudf)
Loose, moist, yellowish brown, Silty, fine to medium SAND; trace gravel;
trace organics
OLD PARALIC DEPOSITS (Qop)
Very dense, wet, light yellowish to grayish brown, Clayey, fine SANDSTONE
-Becomes dense, wet
-Perched groundwater at 9.5 feet
-Becomes medium dense
-Grinding on cobble
-Becomes very dense, saturated, trace rounded gravel
SANTIAGO FORMATION (Tsa)
Very dense, saturated, white, Silty, fine- to coarse-grained SANDSTONE
BORING TERMINATED AT 19.5 FEET
Perched groundwater at 9.5 feet
SM
SC
B1-1
B1-2
B1-3
B1-4
B1-5
B1-6
23.2
25.9
16.6
24.1
14.8
80/11"
49
42
62/11.5"
50/5"
101.4
96.3
113.7
101.8
116.0
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-1,
Log of Boring B 1, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
IR A-300 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING B 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
L.RODRIGUEZ CO
N
T
E
N
T
(
%
)
SAMPLE
NO.02-01-2018
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)46'
G2245-52-01.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2245-52-01
UNDOCUMENTED FILL (Qudf)
Loose, moist, yellowish to grayish brown, Silty, fine to medium SAND; trace
organics
OLD PARALIC DEPOSITS (Qop)
Dense, wet, light yellowish to grayish brown, Silty, fine SANDSTONE
-Becomes very dense
Very stiff, wet, gray to yellowish brown, Sandy CLAYSTONE
-Perched groundwater at 11 inches
-Gravel layer
SANTIAGO FORMATION (Tsa)
Very dense, saturated, light gray, Silty, fine- to coarse-grained SANDSTONE
-Becomes light yellowish brown
BORING TERMINATED AT 19.5 FEET
Perched groundwater at 11.5 feet
SM
SM
CL
SM
B2-1
B2-2
B2-3
B2-4
B2-5
20.2
25.4
26.2
61
75/11"
33
90/10"
50/6"
105.5
93.6
92.7
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-2,
Log of Boring B 2, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
IR A-300 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING B 2
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
L. RODRIGUEZ CO
N
T
E
N
T
(
%
)
SAMPLE
NO.02-01-2018
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)45'
G2245-52-01.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2245-52-01
UNDOCUMENTED FILL (Qudf)
Stiff, moist, yellowish brown, Sandy CLAY; trace gravel; trace organics
OLD PARALIC DEPOSITS (Qop)
Dense, wet, yellowish to grayish brown, Clayey, fine SANDSTONE
-Perched groundwater at 7.5 feet
Stiff, wet, gray to yellowish brown, Silty CLAYSTONE
Medium dense to dense, wet, gray to yellowish brown, Clayey, fine to medium
SANDSTONE
SANTIAGO FORMATION (Tsa)
Very dense, moist, light gray to white, Silty, fine- to coarse-grained
SANDSTONE
BORING TERMINATED AT 19.5 FEET
Perched groundwater at 7.5 feet
CL
SC
CL
SC
SM
B3-1
B3-2
B3-3
B3-4
B3-5
B3-6
22.3
19.6
43.2
50
48
19
90/10"
50/5.5"
103.5
106.9
77.0
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-3,
Log of Boring B 3, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
IR A-300 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING B 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
L. RODRIGUEZ CO
N
T
E
N
T
(
%
)
SAMPLE
NO.02-01-2018
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)43.5'
G2245-52-01.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2245-52-01
UNDOCUMENTED FILL (Qudf)
Medium dense, moist, reddish brown, Silty, fine to medium SAND; trace
organics
OLD PARALIC DEPOSITS (Qop)
Hard/dense, damp, grayish brown, Sandy CLAYSTONE to Clayey, fine to
medium SANDSTONE
Medium dense, damp, yellowish to grayish brown, Silty, fine to medium
SANDSTONE
-Perched groundwater at 8.5 feet
Medium dense, saturated, yellowish to grayish brown, Clayey, fine to medium
SANDSTONE
SANTIAGO FORMATION (Tsa)
Very stiff, moist, greenish brown, Sandy CLAYSTONE
Very dense/hard, moist, light yellowish brown, Clayey, fine- to
medium-grained SANDSTONE to Sandy CLAYSTONE
BORING TERMINATED AT 19.5 FEET
Perched groundwater at 8.5 feet
SM
CL/SC
SM
SC
CL
SC
B4-1
B4-2
B4-3
B4-4
B4-5
B4-6
11.8
4.9
18.5
58
30
35
41
50/6"
122.5
107.2
111.4
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-4,
Log of Boring B 4, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
IR A-300 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING B 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
L. RODRIGUEZ CO
N
T
E
N
T
(
%
)
SAMPLE
NO.02-01-2018
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)42'
G2245-52-01.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2245-52-01
UNDOCUMENTED FILL (Qudf)
Medium dense, reddish brown, Silty, fine to medium SAND; trace gravel
OLD PARALIC DEPOSITS (Qop)
Stiff, wet, dark grayish brown, Sandy CLAYSTONE
Dense, wet, yellowish to grayish brown, Clayey, fine SANDSTONE
-Becomes very dense
-Becomes dense, coarser grained
SANTIAGO FORMATION (Tsa)
Very dense, moist, light gray to white, Silty, fine- to coarse-grained
SANDSTONE
-Seepage at 19 feet
BORING TERMINATED AT 19.5 FEET
SM
CL
SC
SM
B5-1
B5-2
B5-3
B5-4
B5-5
17.6
11.7
18.2
39
77/11.5"
47
50/5"
50/5.5"
115.8
126.1
114.6
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-5,
Log of Boring B 5, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
IR A-300 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING B 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
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SAMPLE
NO.02-01-2018
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
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BY:EQUIPMENT
ELEV. (MSL.)42'
G2245-52-01.GPJ
MATERIAL DESCRIPTION
LI
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... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
G2245-52-01
APPENDIX B
Project No. G2245-52-01 - B-1 - April 8, 2019
APPENDIX B
LABORATORY TESTING
We performed laboratory tests in accordance with generally currently accepted test methods of the
American Society for Testing and Materials (ASTM) or other suggested procedures. We tested selected
soil samples for in-place density and moisture content, maximum dry density and optimum moisture
content, direct shear strength, expansion index, water-soluble sulfate content, unconfined compressive
strength, gradation and consolidation. Tables B-I through B-V and Figures B-1 through B-3 present the
results of our laboratory tests. In addition, the in-place dry density and moisture content test results are
presented on the boring logs in Appendix A.
TABLE B-I SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557
Sample No. Description (Geologic Unit) Maximum Dry Density (pcf)
Optimum Moisture Content (% dry wt.)
B3-1 Yellowish brown, Sandy CLAY (Qudf/Qop) 118.3 13.7
TABLE B-II SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS ASTM D 3080
Sample No. Depth (feet) Geologic Unit
Dry Density (pcf)
Moisture Content (%) Peak [Ultimate1]
Cohesion (psf)
Peak [Ultimate1] Angle of Shear Resistance (degrees) Initial Final
B3-12 0-5 Qudf/Qop 106.6 14.0 23.4 650 [650] 24 [19]
1 Ultimate measured at 0.2-inch deflection. 2 Remolded to a dry density of about 90 percent of the laboratory maximum density.
TABLE B-III SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829
Sample No. Depth (feet) Geologic Unit
Moisture Content (%) Dry Density (pcf)
Expansion Index
ASTM Expansion Classification
2016 CBC Expansion Classification Before Test After Test
B3-1 0-5 Qudf/Qop 13.5 31.4 98.5 105 High Expansive
Project No. G2245-52-01 - B-2 -April 8, 2019
TABLE B-IV SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS CALIFORNIA TEST NO. 417
Sample No. Depth (feet) Geologic Unit Water-Soluble Sulfate (%) Sulfate Exposure Class
B3-1 0-5 Qudf/Qop 0.179 S1
TABLE B-V SUMMARY OF LABORATORY UNCONFINED COMPRESSIVE STRENGTH TEST RESULTS ASTM D 1558
Sample No. Depth (feet) Geologic Unit
Hand Penetrometer Reading, Unconfined Compression Strength (tsf)
Undrained Shear Strength (ksf)
B1-2 3 Qop 4.5+ 4.5+
B1-3 5 Qop 4.5+ 4.5+
B1-4 10 Qop 4.5+ 4.5+
B2-1 2½ Qop 4.5+ 4.5+
B2-2 5 Qop 4.5+ 4.5+
B2-3 10 Qop 4.5+ 4.5+
B3-2 2½ Qop 4.5+ 4.5+
B3-3 5 Qop 4.5+ 4.5+
B3-4 10 Qop 2.5 2.5
B4-2 2½ Qop 4.5+ 4.5+
B4-3 5 Qop 4.5+ 4.5+
B4-4 10 Qop 4.5+ 4.5+
B4-5 15 Tsa 4.5+ 4.5+
B4-6 19 Tsa 4.5+ 4.5+
B5-1 2½ Qop 4.5+ 4.5+
B5-2 5 Qop 3.0 3.0
B5-3 10 Qop 4.5+ 4.5+
0
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0.0010.010.1110
3/8" 4
PROJECT NO. G2245-52-01
U. S. STANDARD SIEVE SIZE
COARSE
3"3/4"1-1/2"8 16 20 30 40
PL
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G2245-52-01.GPJ
B4-3
CARLSBAD, CALIFORNIA
SAND
MEDIUM
5060 100 200
SAMPLE
GEOCON
SILT OR CLAYFINE
GRAIN SIZE IN MILLIMETERS
CLASSIFICATION LL
10
DEPTH (ft)
2690 ROOSEVELT STREET
GRADATION CURVE
Figure B-1
ASTM D422
-6
-4
-2
0
2
4
6
8
10
120.1 1 10 100
Sample Saturated at (ksf)
GEOCON
G2245-52-01.GPJ
Initial Dry Density (pcf)
PROJECT NO. G2245-52-01
Initial Water Content (%)
Initial Saturation (%)100+
2.036.2
SAMPLE NO. B2-3
CARLSBAD, CALIFORNIA
CONSOLIDATION CURVE
86.6
APPLIED PRESSURE (ksf)
Figure B-2
2690 ROOSEVELT STREET
VE
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ASTM D2435
-6
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120.1 1 10 100
Sample Saturated at (ksf)
GEOCON
G2245-52-01.GPJ
Initial Dry Density (pcf)
PROJECT NO. G2245-52-01
Initial Water Content (%)
Initial Saturation (%)23.8
2.04.9
SAMPLE NO. B4-3
CARLSBAD, CALIFORNIA
CONSOLIDATION CURVE
107.2
APPLIED PRESSURE (ksf)
Figure B-3
2690 ROOSEVELT STREET
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ASTM D2435
APPENDIX C
Project No. G2245-52-01 - C-1 - April 8, 2019
APPENDIX C
STORM WATER MANAGEMENT INVESTIGATION
We understand storm water management devices will be used in accordance with the 2016 City of
Carlsbad BMP Design Manual. If not properly constructed, there is a potential for distress to
improvements and properties located hydrologically down gradient or adjacent to these devices.
Factors such as the amount of water to be detained, its residence time, and soil permeability have an
important effect on seepage transmission and the potential adverse impacts that may occur if the storm
water management features are not properly designed and constructed. We have not performed a
hydrogeological study at the site. If infiltration of storm water runoff occurs, downstream properties
may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations
and slabs, or other undesirable impacts as a result of water infiltration.
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United States.
The USDA website also provides the Hydrologic Soil Group. Table C-1 presents the descriptions of
the hydrologic soil groups. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first
letter is for drained areas and the second is for undrained areas. In addition, the USDA website also
provides an estimated saturated hydraulic conductivity for the existing soil.
TABLE C-1 HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These
soils have a high rate of water transmission.
B
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately
fine texture to moderately coarse texture. These soils have a moderate rate of water transmission.
C
Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils
having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These
consist chiefly of clays that have a high shrink-swell potential, soils that have a high-water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow
over nearly impervious material. These soils have a very slow rate of water transmission.
Project No. G2245-52-01 - C-2 - April 8, 2019
The property is underlain by man-made fill and should be classified as Soil Group D. Table C-2
presents the information from the USDA website for the subject property.
TABLE C-2 USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP
Map Unit Name Map Unit Symbol
Approximate Percentage of Property
Hydrologic Soil Group
kSAT of Most Limiting Layer (inches/hour)
Marina loamy coarse sand, 2 to 9 percent slopes MlC 100 B 0.57 – 1.98
In-Situ Testing
The degree of soil compaction or in-situ density has a significant impact on soil permeability and
infiltration. Based on our experience and other studies we performed, an increase in compaction
results/ in-place density results in a general decrease in soil permeability.
Based on discussions with the local regulatory agencies, the infiltration categories include full
infiltration, partial infiltration and no infiltration. Table C-3 presents the definitions of the potential
infiltration categories.
TABLE C-3 INFILTRATION CATEGORIES
Infiltration Category Field Infiltration Rate, I (Inches/Hour) Factored Infiltration Rate, I (Inches/Hour)
Full Infiltration I > 1.0 I > 0.5
Partial Infiltration 0.10 < I < 1.0 0.05 < I < 0.5
No Infiltration (Infeasible) I < 0.10 I < 0.05
The infiltration rate, percolation rates and saturated hydraulic conductivity are different and have
different meanings. Percolation rates tend to overestimate infiltration rates and saturated hydraulic
conductivities by a factor of 10 or more. Table C-4 describes the differences in the definitions.
Project No. G2245-52-01 - C-3 - April 8, 2019
TABLE C-4 SOIL PERMEABILITY DEFINITIONS
Term Definition
Infiltration Rate
The observation of the flow of water through a material into the ground downward into a given soil structure under long term conditions. This is a function of layering of soil, density, pore space, discontinuities and initial moisture content.
Percolation Rate
The observation of the flow of water through a material into the ground downward and laterally into a given soil structure under long term conditions. This is a function of layering of soil, density, pore space, discontinuities and initial moisture content.
Saturated Hydraulic
Conductivity (kSAT, Permeability)
The volume of water that will move in a porous medium under a hydraulic gradient through a unit area. This is a function of density,
structure, stratification, fines content and discontinuities. It is also a function of the properties of the liquid as well as of the porous medium.
The degree of soil compaction or in-situ density has a significant impact on soil permeability and
infiltration. Based on our experience and other studies we performed, an increase in compaction
results in a decrease in soil permeability.
We performed 2 Aardvark Permeameter tests at locations shown on the attached Geologic Map,
Figure 2. The test borings were 4½ inches in diameter. The results of the tests provide parameters
regarding the saturated hydraulic conductivity and infiltration characteristics of on-site soil and
geologic units. Table C-5 presents the results of the estimated field saturated hydraulic conductivity
and estimated infiltration rates obtained from the Aardvark Permeameter tests. The field sheets are
also attached herein. We did not use a factor of safety applied to the test results on the worksheet
values. The designer of storm water devices should apply an appropriate factor of safety. Soil
infiltration rates from in-situ tests can vary significantly from one location to another due to the
heterogeneous characteristics inherent to most soil. Based on a discussion in the County of Riverside
Design Handbook for Low Impact Development Best Management Practices, the infiltration rate
should be considered equal to the saturated hydraulic conductivity rate.
TABLE C-5 FIELD PERMEAMETER INFILTRATION TEST RESULTS
Test
Location
Test Depth
(feet, below grade)
Geologic
Unit
Field-Saturated Infiltration Rate, ksat (inch/hour)
C.4-1 Worksheet Infiltration Rate1, ksat (inch/hour)
P-1 2 Qop 0.008 0.004
P-2 2 Qop 0.183 0.092
Average: 0.096 0.048
1 Using a factor of safety of 2.
Project No. G2245-52-01 - C-4 - April 8, 2019
The test results indicate the approximate infiltration rates range from approximately 0.008 to 0.183
inches per hour (0.004 to 0.092 inches per hour with an applied factor of safety of 2). The average
infiltration rate with an applied factor of safety of 2 is 0.048 inches per hour. Full and partial
infiltration should be considered infeasible at the site because the average infiltration rate is less than
0.05 inches per hour.
Groundwater Elevations
We encountered perched groundwater during our investigation at depths ranging from
approximately 7½ to 11½ feet below the existing ground surface (approximate elevations ranging
from approximately 32½ to 37½ feet MSL). Therefore, infiltration is considered infeasible at the
site.
New or Existing Utilities
Utilities are present on the existing property and within the existing adjacent Roosevelt Street. Full or
partial infiltration should not be allowed in the areas of the utilities to help prevent potential
damage/distress to improvements. Mitigation measures to prevent water from infiltrating the utilities
consist of setbacks, installing cutoff walls around the utilities and installing subdrains and/or installing
liners.
Existing and Planned Structures
Existing structures exist to the north and south and east of the site. Water should not be allowed to
infiltrate in areas where it could affect the existing and neighboring properties and existing and
adjacent structures, improvements and roadways. Mitigation for existing structures consist of not
allowing water infiltration within a 1:1 plane from existing foundations and extending the infiltration
areas at least 10 feet below the existing foundations and into formational materials.
Slopes and Other Geologic Hazards
There are no slopes present or geologic hazards at the site that would preclude infiltration at the site.
Storm Water Evaluation Narrative
The site is underlain by approximately 1 to 3 feet of undocumented fill across the site. In our
experience, fill does not possess infiltration rates appropriate with infiltration. Therefore, infiltration is
considered infeasible within the undocumented fill.
The formational Old Paralic Deposits underlies the undocumented as shallow as 1 to 3 feet deep and
extending to approximately 14 to 19 feet below existing grade. We performed 2 infiltration tests
within the Old Paralic Deposits and the results indicate an infiltration rate of less than 0.05 inches
Project No. G2245-52-01 - C-5 - April 8, 2019
per hour. Infiltration should not be allowed in soils that possess an infiltration rate less than 0.05
inches per hour; therefore, partial and full should be considered infeasible within the Old Paralic
Deposits.
The Santiago Formation exists below the Old Paralic Deposits. We did not perform infiltration testing
within the Santiago Formation due to the depth of the formation. It would be unreasonable and costly
to install storm water devices at depths exceeding approximately 15 feet at the site.
We encountered perched groundwater during our investigation at depths ranging from approximately
7½ and 11½ feet below the existing ground surface. We expect the bottom of planned storm water
infiltration devices will extend to depths of 2 feet or greater below the existing ground surface at the
site, therefore, we expect the bottom of the any planned storm water devices will be within 10 feet of
groundwater. Therefore, infiltration is considered infeasible at the site.
Therefore, due to the characteristics of the onsite soils and the depth of the groundwater relative to the
bottom of planned storm water devices, infiltration should be considered infeasible and any planned
storm water device should be lined.
Storm Water Management Devices
Liners and subdrains should be incorporated into the design and construction of the planned storm
water devices. The liners should be installed on the sides and bottoms of the planned basins and should
be impermeable (e.g. High-density polyethylene, HDPE, with a thickness of about 40 mil or
equivalent Polyvinyl Chloride, PVC) to prevent water migration. The subdrains should be perforated
within the liner area, installed at the base and above the liner, be at least 3 inches in diameter and
consist of Schedule 40 PVC pipe. The subdrains outside of the liner should consist of solid pipe. The
penetration of the liners at the subdrains should be properly waterproofed. The subdrains should be
connected to a proper outlet. The devices should also be installed in accordance with the
manufacturer’s recommendations.
Storm Water Standard Worksheets
The SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility
Condition (Worksheet C.4-1 or I-8) worksheet information to help evaluate the potential for
infiltration on the property. The attached Worksheet I-8 presents the completed information for the
submittal process.
The regional storm water standards also have a worksheet (Worksheet D.5-1 or Form I-9) that helps
the project civil engineer estimate the factor of safety based on several factors. Table C-5 describes the
suitability assessment input parameters related to the geotechnical engineering aspects for the factor of
safety determination.
Project No. G2245-52-01 - C-6 - April 8, 2019
TABLE C-5 SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY SAFETY FACTORS
Consideration High Concern – 3 Points Medium Concern – 2 Points Low Concern – 1 Point
Assessment Methods
Use of soil survey maps or
simple texture analysis to estimate short-term
infiltration rates. Use of well permeameter or
borehole methods without accompanying continuous
boring log. Relatively sparse testing with direct
infiltration methods
Use of well permeameter or borehole methods with accompanying continuous boring log. Direct measurement of infiltration area with localized infiltration measurement methods (e.g., Infiltrometer). Moderate spatial resolution
Direct measurement with localized (i.e. small-
scale) infiltration testing methods at relatively high
resolution or use of extensive test pit
infiltration measurement methods.
Predominant Soil Texture Silty and clayey soils with significant fines Loamy soils Granular to slightly loamy soils
Site Soil Variability
Highly variable soils indicated from site assessment or unknown variability
Soil boring/test pits indicate moderately
homogenous soils
Soil boring/test pits indicate relatively
homogenous soils
Depth to Groundwater/ Impervious Layer <5 feet below facility bottom 5-15 feet below facility bottom >15 feet below facility bottom
Based on our geotechnical investigation and the previous table, Table C-6 presents the estimated
factor values for the evaluation of the factor of safety. This table only presents the suitability
assessment safety factor (Part A) of the worksheet. The project civil engineer should evaluate the
safety factor for design (Part B) and use the combined safety factor for the design infiltration rate.
TABLE C-6
FACTOR OF SAFETY WORKSHEET DESIGN VALUES – PART A1
Suitability Assessment Factor Category Assigned Weight (w) Factor Value (v) Product (p = w x v)
Assessment Methods 0.25 2 0.50
Predominant Soil Texture 0.25 2 0.50
Site Soil Variability 0.25 3 0.75
Depth to Groundwater/ Impervious Layer 0.25 2 0.50
Suitability Assessment Safety Factor, SA = Σp 2.25
1 The project civil engineer should complete Worksheet D.5-1 or Form I-9 using the data on this table. Additional information is required to evaluate the design factor of safety.
Project No. G2245-52-01 - C-7 - April 8, 2019
Categorization of Infiltration Feasibility Condition Form I-8
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed
facility locations greater than 0.5 inches per hour? The response
to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D.
X
Provide basis:
We performed 2 Aardvark Permeameter tests at the site within the Old Paralic Deposits within the low end of the site
where storm water devices will likely be installed. The following presents the results of our field infiltration tests:
P-1 at 2 feet: 0.008 inches/hour (0.004 inches/hour with FOS=2) P-2 at 2 feet: 0.183 inches/hour (0.092 inches/hour with FOS=2)
These tests result in an average of 0.096 inches/hour (0.048 inches/hour with an applied factor of safety of 2).
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2.
X
Provide basis:
Geologic hazards do not exist at the site that would preclude infiltration. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Project No. G2245-52-01 - C-8 - April 8, 2019
Worksheet C.4-1 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow
water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3.
X
Provide basis:
We encountered groundwater during the site investigation at depths ranging from 7½ and 11½ feet below the existing grade. Therefore, infiltration should be considered infeasible at the site Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of
contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3.
X
Provide basis: We do not expect infiltration will cause water balance issues such as seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
Part 1 Result*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a “full infiltration” design. Proceed to Part 2
No Full
Infiltration
*To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings.
Project No. G2245-52-01 - C-9 - April 8, 2019
Worksheet C.4-1 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any
appreciable rate or volume? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D.
X
Provide basis:
We performed 2 Aardvark Permeameter tests at the site within the Old Paralic Deposits within the low end of the site where storm water devices will likely be installed. The following presents the results of our field infiltration tests:
P-1 at 2 feet: 0.008 inches/hour (0.004 inches/hour with FOS=2) P-2 at 2 feet: 0.183 inches/hour (0.092 inches/hour with FOS=2) These tests result in an average of 0.096 inches/hour (0.048 inches/hour with an applied factor of safety of 2). The average infiltration rate at the site is less than 0.05 inches/hour, therefore, partial infiltration should be considered infeasible.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors)
that cannot be mitigated to an acceptable level? The response
to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2.
X
Provide basis: Geologic hazards do not exist at the site that would preclude infiltration.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Project No. G2245-52-01 - C-10 - April 8, 2019
Worksheet C.4-1 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related
concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in
Appendix C.3.
X
Provide basis:
We encountered groundwater during the site investigation at depths ranging from 7½ and 11½ feet below the existing grade. Therefore, infiltration should be considered infeasible at the site. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
8
Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be
based on a comprehensive evaluation of the factors presented in
Appendix C.3.
X
Provide basis: We did not provide a study regarding water rights. However, these rights are not typical in the San Diego County area.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2 Result*
If all answers from row 1-4 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
No Infiltration
*To be completed using gathered site information and best professional judgment considering the definition of MEP in the
MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings.
Aardvark Permeameter Data Analysis
Project Name:Date:2/8/2018
Project Number:By:LR
Borehole Location:Ref. EL (feet, MSL):42.0
Bottom EL (feet, MSL):41.8
Borehole Diameter, d (in.):4.25Borehole Depth, H (feet):2.00 Wetted Area, A (in2):89.68
Distance Between Reservoir & Top of Borehole (in.):29.00Depth to Water Table, s (feet):50.00Height APM Raised from Bottom (in.):2.00Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):46.25Head Height Calculated, h (in.):5.65Head Height Recorded, h (in.):5.50Distance Between Constant Head and Water Table, L (in.):581.65
Reading Time (min)Time Elapsed
(min)
Reservoir Water
Weight (g)
Resevoir Water
Weight (lbs)
Interval Water
Consumption (lbs)
Total Water
Consumption (lbs)
*Water
Consumption Rate
(in3/min)
1 0 17.625
2 5 5.00 17.605 0.020 0.020 0.111
3 10 5.00 17.575 0.030 0.050 0.166
4 15 5.00 17.570 0.005 0.055 0.028
5 20 5.00 17.560 0.010 0.065 0.055
6 25 5.00 17.555 0.005 0.070 0.028
7 30 5.00 17.550 0.005 0.075 0.028
8 35 5.00 17.545 0.005 0.080 0.028
9 40 5.00 17.540 0.005 0.085 0.028
10
111213
14
15
16
17
18
19
20
21
22
23
242526
27
28
0.028
Field-Saturated Hydraulic Conductivity (Infiltration Rate)
Case 1: L/h > 3 K sat =1.40E-04 in/min 0.008 in/hr
2690 Roosevelt Street
G2245-52-01
P-1
Steady Flow Rate, Q (in3/min):
0.0
0.1
0.1
0.2
0.2
0 5 10 15 20 25 30 35 40 45Wa
t
e
r
C
o
n
s
u
m
p
t
i
o
n
Ra
t
e
(
i
n
3/m
i
n
)
Time (min)
Aardvark Permeameter Data Analysis
Project Name:Date:2/8/2018
Project Number:By:LR
Borehole Location:Ref. EL (feet, MSL):41.0
Bottom EL (feet, MSL):40.8
Borehole Diameter, d (in.):4.25Borehole Depth, H (feet):2.00 Wetted Area, A (in2):102.94
Distance Between Reservoir & Top of Borehole (in.):28.00Depth to Water Table, s (feet):50.00Height APM Raised from Bottom (in.):3.00Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):44.25Head Height Calculated, h (in.):6.65Head Height Recorded, h (in.):6.50Distance Between Constant Head and Water Table, L (in.):582.65
Reading Time (min)Time Elapsed
(min)
Reservoir Water
Weight (g)
Resevoir Water
Weight (lbs)
Interval Water
Consumption (lbs)
Total Water
Consumption (lbs)
*Water
Consumption Rate
(in3/min)
1 1 16.875
2 6 5.00 16.734 0.141 0.141 0.779
3 11 5.00 16.609 0.126 0.266 0.696
4 16 5.00 16.473 0.136 0.402 0.751
5 21 5.00 16.337 0.136 0.538 0.751
6 26 5.00 16.201 0.136 0.674 0.751
7 31 5.00 16.066 0.136 0.809 0.751
8 36 5.00 15.930 0.136 0.945 0.751
9
10
111213
14
15
16
17
18
19
20
21
22
23
242526
27
28
0.751
Field-Saturated Hydraulic Conductivity (Infiltration Rate)
Case 1: L/h > 3 K sat =3.05E-03 in/min 0.183 in/hr
2690 Roosevelt Street
G2245-52-01
P-2
Steady Flow Rate, Q (in3/min):
0.0
0.2
0.4
0.6
0.8
1.0
0 5 10 15 20 25 30 35 40Wa
t
e
r
C
o
n
s
u
m
p
t
i
o
n
Ra
t
e
(
i
n
3/m
i
n
)
Time (min)
APPENDIX D
APPENDIX D RECOMMENDED GRADING SPECIFICATIONS
FOR 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA PROJECT NO. G2245-52-01
GI rev. 07/2015
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon. The recommendations contained
in the text of the Geotechnical Report are a part of the earthwork and grading specifications
and shall supersede the provisions contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
GI rev. 07/2015
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than
12 inches in maximum dimension and containing at least 40 percent by weight of
material smaller than ¾ inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than
4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than
12 inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than ¾ inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
GI rev. 07/2015
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1½ inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
Geocon and the property owner. Concrete fragments that are free of reinforcing steel may
be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this
document.
GI rev. 07/2015
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Remove All
Unsuitable Material
As Recommended By
Consultant
Finish Grade Original Ground
Finish Slope Surface
Slope To Be Such That
Sloughing Or Sliding
Does Not Occur Varies
“B”
See Note 1
No Scale
See Note 2
1
2
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant.
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
GI rev. 07/2015
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
GI rev. 07/2015
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
GI rev. 07/2015
6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
GI rev. 07/2015
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of “passes” have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for “piping” of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. SUBDRAINS
7.1 The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
GI rev. 07/2015
TYPICAL CANYON DRAIN DETAIL
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
GI rev. 07/2015
TYPICAL STABILITY FILL DETAIL
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
GI rev. 07/2015
7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
GI rev. 07/2015
TYPICAL HEADWALL DETAIL
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an “as-built” map showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain. The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
GI rev. 07/2015
8. OBSERVATION AND TESTING
8.1 The Consultant shall be the Owner’s representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
8.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
8.5 We should observe the placement of subdrains, to check that the drainage devices have
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method.
GI rev. 07/2015
8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9. PROTECTION OF WORK
9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
9.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
10. CERTIFICATIONS AND FINAL REPORTS
10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
10.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
Project No. G2245-52-01 April 8, 2019
LIST OF REFERENCES
1. 2016 California Building Code, California Code of Regulations, Title 24, Part 2, based on the 2015 International Building Code, prepared by California Building Standards Commission, dated July, 2016.
2. ACI 318-14, Building Code Requirements for Structural Concrete and Commentary on Building Code Requirements for Structural Concrete, prepared by the American Concrete Institute, dated September, 2014.
3. ACI 330-08, Guide for the Design and Construction of Concrete Parking Lots, American Concrete Institute, June 2008.
4. Anderson, J. G., T. K. Rockwell, and D. C. Agnew, Past and Possible Future Earthquakes of
Significance to the San Diego Region: Earthquake Spectra, v. 5, no. 2, p. 299-333, 1989.
5. ASCE 7-10, Minimum Design Loads for Buildings and Other Structures, Second Printing,
April 6, 2011.
6. Boore, D. M., and G. M Atkinson (2008), Ground-Motion Prediction for the Average
Horizontal Component of PGA, PGV, and 5%-Damped PSA at Spectral Periods Between 0.01
and 10.0 S, Earthquake Spectra, Volume 24, Issue 1, pp. 99-138, February 2008.
7. California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic
Hazard Assessment for the State of California, Open File Report 96-08, 1996.
8. California Emergency Management Agency, California Geological Survey, University of
Southern California (2009). Tsunami Inundation Map for Emergency Planning, State of
California, County of San Diego, Point Loma Triangle, Scale 1:24,000, dated June 1.
9. California Geologic Survey, State of California Earthquake Fault Zones, Point Loma
Quadrangle, May 1, 2003.
10. California Geologic Survey (2008), Special Publication 117, Guidelines For Evaluating and
Mitigating Seismic Hazards in California, Revised and Re-adopted September 11.
11. Campbell, K. W., and Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean
Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra
for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication in the
NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, February
2008.
12. Chiou, Brian S. J., and Robert R. Youngs, A NGA Model for the Average Horizontal
Component of Peak Ground Motion and Response Spectra, preprint for article to be published
in NGA Special Edition for Earthquake Spectra, Spring 2008.
13. Jennings, C. W., 1994, California Division of Mines and Geology, Fault Activity Map of
California and Adjacent Areas, California Geologic Data Map Series Map No. 6.
LIST OF REFERENCES (Concluded)
Project No. G2245-52-01 April 8, 2019
14. Kennedy, M. P., and S. S. Tan, 2008, Geologic Map of Oceanside 30’x60’ Quadrangle,
California, USGS Regional Map Series Map No. 2, Scale 1:100,000.
15. Risk Engineering, EZFRISK, 2015.
16. Structural Engineers Association of California (SEAOC) and Office of Statewide Health Planning and Development (OSHPD), Seismic Design Maps, https://seismicmaps.org/,
accessed January 11, 2019.
17. Unpublished Geotechnical Reports and Information, Geocon Incorporated.
GROCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL MATERIALSO
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159
Project No. G2245-52-01
December 18, 2019
Kitchell Development Company
1555 Camino Del Mar, Suite 307
Del Mar, California 92014
Attention: Mr. Marne Bouillon
Subject: UPDATE GEOTECHNICAL RECOMMENDATIONS
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. [Architectural Plans for] 2690 Roosevelt Street, Carlsbad, California, prepared by Starck Architecture and Planning, dated November 22, 2019 (Project No. G2068-1104).
Dear Mr. Bouillon:
In accordance with the request of Damien Leyva of Starck Architecture and Planning, we prepared this
letter to provide updated recommendations for the 2690 Roosevelt Street residential project located in
the City of Carlsbad, California. Specifically, have included 2019 California Building Code seismic
design criteria. The remainder of the recommendations presents in the referenced geotechnical
investigation report remain applicable to the design and construction of the proposed project.
PROJECT DESCRIPTION
The subject site is located north of the intersection of Roosevelt Street and Beech Avenue in a
residential area in the City of Carlsbad, California. The site currently consists of a single-family
residence that has been modified to commercial space. The site is accessed from Roosevelt Street by a
concrete drive to north and a gravel driveway to the south of the structure with parking available to the
east of the building. The property slopes gently to the northwest with elevations ranging from about 41
to 47 feet above Mean Sea Level (MSL). Overhead utility lines exist fronting Roosevelt Street.
We understand proposed development will consist of demolishing the existing structure and
constructing three, 3-story, residential buildings (Buildings A through C) consisting of 9 units with
Geocon Project No. G2245-52-01 - 2 - December 18, 2019
accommodating garages, driveways, utilities, landscaping and hardscape. We expect cuts and fills less
than approximately 3 feet will be required to achieve planned grades, and we expect the planned
structures will be supported on shallow foundations with a concrete-slab-on-grade. We previously
performed the referenced geotechnical investigation report and encountered approximately 1 to 3 feet
of undocumented fill (Qudf) overlying Old Paralic Deposits (Qop).
SEISMIC DESIGN CRITERIA – 2019 CALIFORNIA BUILDING CODE
We understand the plans will be submitted using the 2019 California Building Code (CBC). Table 1
summarizes site-specific design criteria obtained from the 2019 California Building Code (CBC;
Based on the 2018 International Building Code [IBC] and ASCE 7-16), Chapter 16 Structural Design,
Section 1613 Earthquake Loads. We used the computer program Seismic Design Maps, provided by
the Structural Engineers Association (SEA) to calculate the seismic design parameters. The short
spectral response uses a period of 0.2 second. We evaluated the Site Class based on the discussion in
Section 1613.2.2 of the 2019 CBC and Table 20.3-1 of ASCE 7-16. The values presented herein are
for the risk-targeted maximum considered earthquake (MCER). Sites designated as Site Class D, E and
F may require additional analyses if requested by the project structural engineer and client.
TABLE 1
2019 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2019 CBC Reference
Site Class C Section 1613.2.2
MCER Ground Motion Spectral Response Acceleration –
Class B (short), SS 1.077g Figure 1613.2.1(1)
MCER Ground Motion Spectral Response Acceleration –
Class B (1 sec), S1 0.390g Figure 1613.2.1(2)
Site Coefficient, FA 1.200 Table 1613.2.3(1)
Site Coefficient, FV 1.500* Table 1613.2.3(2)
Site Class Modified MCER Spectral Response
Acceleration (short), SMS
1.292g Section 1613.2.3 (Eqn
16-36)
Site Class Modified MCER Spectral Response
Acceleration – (1 sec), SM1 0.584g* Section 1613.2.3 (Eqn
16-37)
5% Damped Design
Spectral Response Acceleration (short), SDS 0.861g Section 1613.2.4 (Eqn
16-38)
5% Damped Design
Spectral Response Acceleration (1 sec), SD1 0.390g* Section 1613.2.4 (Eqn
16-39)
* Using the code-based values presented in this table, in lieu of a performing a ground motion hazard analysis,
requires the exceptions outlined in ASCE 7-16 Section 11.4.8 be followed by the project structural engineer. Per
Section 11.4.8 of ASCE/SEI 7-16, a ground motion hazard analysis should be performed for projects for Site Class
“E” sites with Ss greater than or equal to 1.0g and for Site Class “D” and “E” sites with S1 greater than 0.2g.
Section 11.4.8 also provides exceptions which indicates that the ground motion hazard analysis may be waived
provided the exceptions are followed.
Geocon Project No. G2245-52-01 - 3 - December 18, 2019
Table 2 presents the mapped maximum considered geometric mean (MCEG) seismic design
parameters for projects located in Seismic Design Categories of D through F in accordance with
ASCE 7-16.
TABLE 2
ASCE 7-16 PEAK GROUND ACCELERATION
Parameter Value ASCE 7-16 Reference
Site Class C Section 1613.2.2 (2019 CBC)
Mapped MCEG Peak Ground Acceleration,
PGA 0.475g Figure 22-7
Site Coefficient, FPGA 1.200 Table 11.8-1
Site Class Modified MCEG Peak Ground
Acceleration, PGAM 0.570g Section 11.8.3 (Eqn 11.8-1)
Conformance to the criteria in Tables 1 and 2 for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will not occur if a large
earthquake occurs. The primary goal of seismic design is to protect life, not to avoid all damage, since
such design may be economically prohibitive.
The project structural engineer and architect should evaluate the appropriate Risk Category and
Seismic Design Category for the planned structures. The values presented herein assume a Risk
Category of II and resulting in a Seismic Design Category D. Table 3 presents a summary of the risk
categories.
TABLE 3
ASCE 7-16 RISK CATEGORIES
Risk Category Building Use Examples
I Low risk to Human Life at Failure Barn, Storage Shelter
II Nominal Risk to Human Life at Failure (Buildings Not Designated as I, III or IV) Residential, Commercial and Industrial Buildings
III Substantial Risk to Human Life at Failure Theaters, Lecture Halls, Dining Halls, Schools, Prisons, Small Healthcare Facilities, Infrastructure Plants, Storage for Explosives/Toxins
IV Essential Facilities
Hazardous Material Facilities, Hospitals, Fire and Rescue, Emergency Shelters, Police Stations, Power Stations, Aviation Control Facilities, National Defense, Water Storage
Geocon Project No. G2245-52-01 - 4 - December 18, 2019
Should you have any questions regarding this report, or if we may be of further service, please contact
the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Lilian E. Rodriguez
RCE 83227
Shawn Foy Weedon
GE 2714
LER:SFW:am
(e-mail) Addressee
STORM WATER
MANAGEMENT INVESTIGATION
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
PREPARED FOR
ROOSEVELT NINE LLC
CARDIFF, CALIFORNIA
APRIL 21, 2020
REVISED OCTOBER 24, 2022
PROJECT NO. G2245-52-01
Project No. G2245-52-01
April 21, 2020
Revised October 24, 2022
Roosevelt Nine LLC
2033 San Elijo Avenue, Suite 423
Cardiff, California 92014
Attention: Mr. Randolf Cherewick
Subject: STORM WATER MANAGEMENT INVESTIGATION
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
Reference: Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by
Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
Dear Mr. Cherewick:
In accordance with your request, we herein submit the results of our storm water management
investigation for the property located at 2690 Roosevelt Street in the City of Carlsbad, California (see
Figure 1, Vicinity Map).
SITE AND PROJECT DESCRIPTION
The subject site is located north of the intersection of Roosevelt Street and Beech Avenue in a residential
area in the City of Carlsbad, California. The site currently consists of a single-family residence that has
been modified to commercial space. The site is accessed from Roosevelt Street by a concrete drive to
north and a gravel driveway to the south of the structure with parking available to the east of the building.
The property slopes gently to the northwest with elevations ranging from about 41 to 47 feet above
Mean Sea Level (MSL). Overhead utility lines exist fronting Roosevelt Street.
We prepared the referenced geotechnical investigation report for the site and proposed development.
Our field investigation consisted of advancing 5 exploratory borings (Borings B-1 through B-5) to a
maximum depth of about 19½ feet and performing 2 infiltration tests. During our investigation, we
encountered one surficial soil unit (consisting of undocumented fill) and one formational unit (consisting
of Old Paralic Deposits). We encountered undocumented fill in our borings to depths ranging from about
1 to 3 feet overlying the Old Paralic Deposits. The occurrence, distribution, and description of each unit
Geocon Project No. G2245-52-01 - 2 - April 21, 2022
Revised October 24, 2022
encountered are shown on the Geologic Map, Figure 2 and on the boring logs in Appendix A of the
referenced report.
STORM WATER MANAGEMENT INVESTIGATION
We understand storm water management devices will be used in accordance with the 2021 City of
Carlsbad BMP Design Manual. If not properly constructed, there is a potential for distress to
improvements and properties located hydrologically down gradient or adjacent to these devices. Factors
such as the amount of water to be detained, its residence time, and soil permeability have an important
effect on seepage transmission and the potential adverse impacts that may occur if the storm water
management features are not properly designed and constructed. We have not performed a
hydrogeological study at the site. If infiltration of storm water runoff occurs, downstream properties
may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations and
slabs, or other undesirable impacts as a result of water infiltration.
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United States.
The USDA website also provides the Hydrologic Soil Group. Table 1 presents the descriptions of the
hydrologic soil groups. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter
is for drained areas and the second is for undrained areas. In addition, the USDA website also provides
an estimated saturated hydraulic conductivity for the existing soil.
TABLE 1
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A
Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist
mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a
high rate of water transmission.
B
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately
deep or deep, moderately well drained or well drained soils that have moderately fine texture to
moderately coarse texture. These soils have a moderate rate of water transmission.
C
Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a
layer that impedes the downward movement of water or soils of moderately fine texture or fine
texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist
chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that
have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
Geocon Project No. G2245-52-01 - 3 - April 21, 2022
Revised October 24, 2022
Table 2 presents the information from the USDA website for the subject property.
TABLE 2
USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP*
Map Unit Name Map Unit Symbol
Approximate Percentage of Property
Hydrologic Soil Group
kSAT of Most Limiting Layer (Inches/ Hour)
Marina loamy coarse
sand, 2 to 9 percent slopes MlC 100 B 0.57 – 1.98
*The areas of the property that possess fill materials should be considered to possess a Hydrologic Soil Group D.
In Situ Testing
We performed 2 constant-head infiltration tests using the Aardvark permeameter at the locations shown
on the Geologic Map, Figure 2. Table 3 presents the results of the infiltration tests. The field data sheets
are attached herein. We applied a feasibility factor of safety of 2.0 to our estimated infiltration rates. The
designer of storm water devices should apply an appropriate factor of safety, where necessary. Soil
infiltration rates from in-situ tests can vary significantly from one location to another due to the
heterogeneous characteristics inherent to most soil.
TABLE 3
INFILTRATION TEST RESULTS
Test No. Geologic Unit
Test Depth (feet, below grade)
Field-Saturated Hydraulic Conductivity/Infiltration Rate, ksat (inch/hour)
Worksheet Infiltration Rate1 (inch/hour)
P-1 Qop 2 0.008 0.004
P-2 Qop 2 0.183 0.092
Average 0.10 0.05
1 Using a Factor of Safety of 2.
Infiltration categories include full infiltration, partial infiltration and no infiltration. Table 4 presents the
commonly accepted definitions of the potential infiltration categories based on the infiltration rates.
TABLE 4 INFILTRATION CATEGORIES
Infiltration Category Field Infiltration Rate, I (Inches/Hour) Factored Infiltration Rate1, I (Inches/Hour)
Full Infiltration I > 1.0 I > 0.5
Partial Infiltration 0.10 < I < 1.0 0.05 < I < 0.5
No Infiltration (Infeasible) I < 0.10 I < 0.05
1 Using a Factor of Safety of 2.
Geocon Project No. G2245-52-01 - 4 - April 21, 2022
Revised October 24, 2022
The test results indicate the approximate infiltration rates range from approximately 0.008 to
0.183 inches per hour (0.004 to 0.092 inches per hour with an applied factor of safety of 2). The average
infiltration rate with an applied factor of safety of 2 is 0.05 inches per hour. Full infiltration should be
considered infeasible, however partial infiltration should be considered feasible at the site because the
average infiltration rate is between 0.05 and 0.5 inches per hour.
GEOTECHNICAL CONSIDERATIONS
Groundwater Elevations
We encountered perched groundwater/seepage during our investigation at depths ranging from
approximately 7½ to 11½ feet below the existing ground surface (approximate elevations ranging from
approximately 32½ to 37½ feet MSL). We expect permanent groundwater is approximately 40 feet
below the existing ground surface.
New or Existing Utilities
Utilities are present on the existing property and within the existing adjacent Roosevelt Street. Full or
partial infiltration should not be allowed in the areas of the utilities to help prevent potential
damage/distress to improvements. Mitigation measures to prevent water from infiltrating the utilities
consist of setbacks, installing cutoff walls around the utilities and installing subdrains and/or installing
liners.
Existing Structures
Existing structures exist to the north and south and east of the site. Water should not be allowed to
infiltrate in areas where it could affect the existing and neighboring properties and existing and adjacent
structures, improvements and roadways. Mitigation for existing structures consist of not allowing water
infiltration within a 1:1 plane from existing foundations and extending the infiltration areas at least 10
feet from the existing foundations and into formational materials.
Soil or Groundwater Contamination
We are unaware of contaminated soil on the property. Therefore, infiltration associated with this risk is
considered feasible.
CONCLUSIONS AND RECOMMENDATIONS
Storm Water Evaluation Narrative
The site is underlain by approximately 1 to 3 feet of undocumented fill across the site. In our experience,
fill does not possess infiltration rates appropriate with infiltration. Therefore, infiltration is considered
Geocon Project No. G2245-52-01 - 5 - April 21, 2022
Revised October 24, 2022
infeasible within the undocumented fill and we performed our infiltration tests in the relatively shallow
Old Paralic Deposits. The formational Old Paralic Deposits underlie the undocumented as shallow as 1
to 3 feet deep and extending to approximately 14 to 19 feet below existing grade. We performed 2
infiltration tests within the Old Paralic Deposits and the results indicate an infiltration rate of
approximately 0.05 inches per hour.
The Santiago Formation exists below the Old Paralic Deposits. We did not perform infiltration testing
within the Santiago Formation due to the depth of the formation. It would be unreasonable and costly to
install storm water devices at depths exceeding approximately 15 feet at the site.
We encountered perched groundwater/seepage during our investigation at depths ranging from
approximately 7½ and 11½ feet below the existing ground surface. We expect permanent groundwater
exist approximately 40 feet below existing grade. We expect the bottom of planned storm water
infiltration devices will extend to depths of 2 feet or greater below the existing ground surface at the
site.
Storm Water Evaluation Conclusion
Based on the results of our infiltration tests performed within the existing formational materials
(approximately 0.05 inches per hour), and the depth of groundwater relative to the bottom of planned
storm water devices, we opine full infiltration on the property is considered infeasible. The site can be
classified as “Partial Infiltration” condition due to the rates ranging between 0.05 to 0.5 inches per hour.
Geocon understands permeable pavers may be utilized in the driveway and patio walkway areas
allowing “Partial Infiltration” if the following criteria are met:
Foundations adjacent to permeable paver areas are deepened a minimum of 30 inches below
lowest adjacent grade.
A subdrain should be installed and connected to an appropriate outlet (e.g. storm drain catch
basin). The subdrain should consist of a minimum 4-inch perforated pipe (Schedule 40 PVC or
similar), covered with washed ¾-inch gravel and wrapped in filter fabric (Mirafi 140 N or
equivalent).
Storm Water Management Devices
Liners and subdrains should be incorporated into the design and construction of the planned storm water
devices. The liners should be impermeable (e.g. High-density polyethylene, HDPE, with a thickness of
about 30 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration. The subdrains should
be perforated within the liner area, installed at the base and above the liner, be at least 3 inches in
diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner should consist of solid
pipe. The penetration of the liners at the subdrains should be properly waterproofed. The subdrains
Geocon Project No. G2245-52-01 - 6 - April 21, 2022
Revised October 24, 2022
should be connected to a proper outlet. The devices should also be installed in accordance with the
manufacturer’s recommendations.
Storm Water Standard Worksheets
We evaluated the proposed project with respect to the infiltration restrictions contained in Table D.1-
1 in Appendix D of the City of Carlsbad BMP Design Manual (see Table 5).
TABLE 5
CONSIDERATIONS FOR GEOTECNICAL ANALSIS OF INFILTRATION RESTRICTIONS
(TABLE D.1-1 OF APPENDIX D)
Restriction Element
Is Element Applicable? (Yes/No)
Mandatory Considerations
BMP is within 100’ of Contaminated Soils No
BMP is within 100’ of Industrial Activities Lacking Source Control No
BMP is within 100’ of Well/Groundwater Basin No
BMP is within 50’ of Septic Tanks/Leach Fields No
BMP is within 10’ of Structures/Tanks/Walls No
BMP is within 10’ of Sewer Utilities No
BMP is within 10’ of Groundwater Table No
BMP is within Hydric Soils No
BMP is within Highly Liquefiable Soils and has Connectivity to Structures No
BMP is within 1.5 Times the Height of Adjacent Steep Slopes (≥25%) No
City Staff has Assigned “Restricted” Infiltration Category No
Optional Considerations
BMP is within Predominantly Type D Soil Yes
BMP is within 10’ of Property Line No
BMP is within Fill Depths of ≥5’ (Existing or Proposed) No
BMP is within 10’ of Underground Utilities No
BMP is within 250’ of Ephemeral Stream No
Other (Provide detailed geotechnical support) – See discussion above No
Result
Based on examination of the best available information, I have not identified any restrictions above.
XUnrestricted
Based on examination of the best available information, I have identified one or more restrictions above.
The BMP manual also has a worksheet (Table D.2-4 of Appendix D) that helps the project civil engineer
estimate the factor of safety based on several factors. Table 6 describes the suitability assessment input
parameters related to the geotechnical engineering aspects for the factor of safety determination.
Geocon Project No. G2245-52-01 - 7 - April 21, 2022
Revised October 24, 2022
TABLE 6
GUIDANCE FOR DETERMINING INDIVIDUAL FACTOR VALUES – PART A
(TABLE D.2-4 OF APPENDIX D)
Consideration High Concern – 3 Points Medium Concern – 2 Points Low Concern – 1 Point
Infiltration Test Method Any At least 2 tests of any kind within 50’ of BMP
At least 4 tests within BMP footprint, OR Large/Small Scale Pilot Infiltration Testing over at least 5% of BMP footprint.
Soil Texture Class Unknown, Silty, or Clayey Loamy Granular/Slightly Loamy
Site Variability Unknown or High Moderately Homogenous Significantly Homogenous
Depth to Groundwater/ Obstruction <5’ below BMP 5-15’ below BMP >15’ below BMP
Table 7 presents the estimated safety factor values for the evaluation of the factor of safety. This table
only presents the suitability assessment safety factor (Part A) of the worksheet. The project civil engineer
should evaluate the safety factor for design (Part B) and use the combined safety factor for the design
infiltration rate.
TABLE 7
DETERMINATION OF SAFETY FACTOR
(TABLE D.2-3 OF APPENDIX D)
Consideration Assigned Weight (w) Factor Value (v) Product (p = w x v)
Suitability Assessment(A)
Infiltration Testing Method 0.25 2 0.50
Soil Texture Class 0.25 2 0.50
Site Variability 0.25 3 0.75
Depth to Groundwater/Obstruction 0.25 1 0.25
Suitability Assessment Safety Factor, SA = p 2.0
Design
(B)
Pretreatment *
Refer to Table D.2-4
*
Resiliency * *
Compaction * *
Design Safety Factor, SB = p *
Safety Factor, S = SA x SB(Must be always greater than or equal to 2)*
*The civil engineer should evaluate the “Design (B)” factors and the Safety Factor, S.
Geocon Project No. G2245-52-01 - 8 - April 21, 2022
Revised October 24, 2022
Table 8 presents the elements for determining the design infiltration rate (Table D.2-1 of Appendix D).
The civil engineer should evaluate the Safety Factor, S and Design Infiltration Rate. We also included
herein the original I-8 Form from previous submittals for consistency with the current submittal process.
TABLE 8
ELEMENTS FOR DETERMINATION OF DESIGN INFILTRATION RATES
Item Value
Initial Infiltration Rate
Identify per Section D.2.1 0.10 Inches/Hour
Corrected Infiltration RateIdentify per Section D.2.2 0.05 Inches/Hour
Safety FactorIdentify per Section D.2.3 *
Design Infiltration RateCorrected Infiltration Rate/Safety Factor *Inches/Hour
*The civil engineer should evaluate the Safety Factor and Design Infiltration Rate.
If you have any questions regarding this correspondence, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Dylan Thomas
PG 9857
Shawn Foy Weedon
GE 2714
DT:SFW:arm
(e-mail) Addressee
SITESITE
NO SCALE
FIG. 1
THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH,
SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS
NOT INTENDED FOR CLIENT'S USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT
SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT
OF SUCH USE OR RELIANCE BY CLIENT.
VICINITY MAP
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. G2245 - 52 - 01LR / RA
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/05/2019 2:21PM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\DETAILS\G2245-52-01 VicinityMap.dwg
DATE 04 - 08 - 2019
R
O
O
S
E
V
E
L
T
S
T
R
E
E
T
APPROX. LIMITS
OF PROJECT
B-4 B-2
B-3
B-5
B-1
P-1
P-2
Qudf/
Qudf/
PROPOSED BUILDING PROPOSED BUILDING
PROPOSED BUILDINGPROPOSED BUILDING
GEOLOGIC MAP 2
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159PROJECT NO. G2245 - 52 - 01
DATE 04 - 08 - 2019FIGURE
GEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:04/05/2019 2:21PM | By:RUBEN AGUILAR | File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\SHEETS\G2245-52-01 GeologicMap.dwg
GEOCON LEGEND
........UNDOCUMENTED FILL
........APPROX. LOCATION OF BORING
Qudf
B-5
P-2 ........APPROX. LOCATION OF INFILTRATION TEST
........OLD PARALIC DEPOSITS (Dotted Where Buried)Qop
Categorization of Infiltration Feasibility Condition Form I-8
Part 1 – Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed
facility locations greater than 0.5 inches per hour? The response
to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2 and Appendix
D.
X
Provide basis:
Geocon Incorporated performed infiltration testing as part of a geotechnical investigation for the site as summarized in
the report titled: Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon
Incorporated, dated April 8, 2019 (Project No. G2245-52-01) and attached letter.
Geocon Incorporated performed 2 Aardvark Permeameter tests at the site within the Old Paralic Deposits within the
low end of the site where storm water devices will likely be installed. The following presents the results of the field
infiltration tests:
P-1 at 2 feet: 0.008 inches/hour (0.004 inches/hour with FOS=2)
P-2 at 2 feet: 0.183 inches/hour (0.092 inches/hour with FOS=2)
These tests result in an average of 0.10 inches/hour (0.05 inches/hour with an applied factor of safety of 2), less than
0.5 inches per hour.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot
be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2.
X
Provide basis:
The potential geologic hazards at the site are summarized in the geotechnical report prepared by Geocon Incorporated
(Project No. G2245-52-01, dated April 8, 2019) and attached letter. Geologic hazards do not exist at the site that
would preclude infiltration.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Worksheet C.4-1 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of groundwater contamination (shallow
water table, storm water pollutants or other factors) that cannot
be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
X
Provide basis:
The geotechnical investigation performed by Geocon Incorporated (Project No. G2245-52-01, dated April 8, 2019)
included drilling 5 borings to depths up to approximately 20 feet. Groundwater was encountered in the borings at depths
ranging from 7½ and 11½ feet below the existing grade. Geocon understands permeable pavers may be utilized in the driveway
and patio walkway areas allowing “Partial Infiltration”. Partial Infiltration” may be allowed if the following criteria are met:
-Foundations adjacent to permeable paver areas are deepened a minimum of 30 inches below lowest adjacent grade.
-A subdrain should be installed and connected to an appropriate outlet (e.g. storm drain catch basin). The subdrain should consist of
a minimum 4-inch perforated pipe (Schedule 40 PVC or similar), covered with washed ¾-inch gravel and wrapped in filter fabric
(Mirafi 140 N or equivalent).
4
Can infiltration greater than 0.5 inches per hour be allowed
without causing potential water balance issues such as change
of seasonality of ephemeral streams or increased discharge of
contaminated groundwater to surface waters? The response to
this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
X
Provide basis:
Geocon Incorporated does not expect infiltration will cause water balance issues such as seasonality of ephemeral
streams or increased discharge of contaminated groundwater to surface waters.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 1
Result*
If all answers to rows 1 – 4 are “Yes” a full infiltration design is potentially
feasible.The feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but
would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
No Full
Infiltration
*To be completed using gathered site information and best professional judgment considering the definition of MEP in the
MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings.
Worksheet C.4-1 Page 3 of 4
Part 2 –Partial Infiltration vs. No Infiltration Feasibility ScreeningCriteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any
appreciable rate or volume? The response to this Screening
Question shall be based on a comprehensive evaluation of the
factors presented in Appendix C.2 and Appendix D.
X
Provide basis:
Geocon Incorporated performed infiltration testing as part of a geotechnical investigation for the site as summarized in the report titled:
Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated April 8, 2019 (Project No.
G2245-52-01) and the attached letter.
Geocon Incorporated performed 2 Aardvark Permeameter tests at the site within the Old Paralic Deposits within the low end of the site where storm
water devices will likely be installed. The following presents the results of our field infiltration tests:
P-1 at 2 feet: 0.008 inches/hour (0.004 inches/hour with FOS=2)
P-2 at 2 feet: 0.183 inches/hour (0.092 inches/hour with FOS=2)
These tests result in an average of 0.10 inches/hour (0.05 inches/hour with an applied factor of safety of 2). The average infiltration rate at the site
is 0.05 inches/hour, therefore, partial infiltration should be considered feasible.
Geocon understands permeable pavers may be utilized in the driveway and patio walkway areas . “Partial Infiltration” may be allowed if the
following criteria are met:
-Foundations adjacent to permeable paver areas are deepened a minimum of 30 inches below lowest adjacent grade.
-A subdrain should be installed and connected to an appropriate outlet (e.g. storm drain catch basin). The subdrain should consist of a minimum 4-
inch perforated pipe (Schedule 40 PVC or similar), covered with washed ¾-inch gravel and wrapped in filter fabric (Mirafi 140 N or equivalent).
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed
without increasing risk of geotechnical hazards (slope
stability, groundwater mounding, utilities, or other factors)
that cannot be mitigated to an acceptable level? The response
to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2.
X
Provide basis:
The potential geologic hazards at the site are summarized in the geotechnical report prepared by Geocon Incorporated
(Project No. G2245-52-01, dated April 8, 2019) and attached letter. Geologic hazards do not exist at the site that
would preclude infiltration.
Geocon understands permeable pavers may be utilized in the driveway and patio walkway areas. Partial Infiltration may be allowed if
the following criteria are met:
-Foundations adjacent to permeable paver areas are deepened a minimum of 30 inches below lowest adjacent grade.
-A subdrain should be installed and connected to an appropriate outlet (e.g. storm drain catch basin). The subdrain should consist of
a minimum 4-inch perforated pipe (Schedule 40 PVC or similar), covered with washed ¾-inch gravel and wrapped in filter fabric
(Mirafi 140 N or equivalent).
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Worksheet C.4-1 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed
without posing significant risk for groundwater related
concerns (shallow water table, storm water pollutants or other
factors)? The response to this Screening Question shall be based
on a comprehensive evaluation of the factors presented in
Appendix C.3.
X
Provide basis:
The geotechnical investigation performed by Geocon Incorporated (Project No. G2245-52-01, dated April 8, 2019) included drilling 5
borings to depths up to approximately 20 feet. Groundwater/seepage was encountered in the borings at depths ranging from 7½ and 11½
feet below the existing grade. Geocon understands permeable pavers may be utilized in the driveway and patio walkway areas allowing
“Partial Infiltration” if the following criteria are met:
-Foundations adjacent to permeable paver areas are deepened a minimum of 30 inches below lowest adjacent grade.
-A subdrain should be installed and connected to an appropriate outlet (e.g. storm drain catch basin). The subdrain should consist of a
minimum 4-inch perforated pipe (Schedule 40 PVC or similar), covered with washed ¾-inch gravel and wrapped in filter fabric
(Mirafi 140 N or equivalent).
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
8
Can infiltration be allowed without violating downstream
water rights? The response to this Screening Question shall be
based on a comprehensive evaluation of the factors presented in
Appendix C.3.
X
Provide basis:
Geocon Incorporated does not provide a study regarding water rights. However, these rights are not typical in the San Diego County
area.
Geocon understands permeable pavers may be utilized in the driveway and patio walkway areas. “Partial Infiltration” may be allowed
if the following criteria are met:
-Foundations adjacent to permeable paver areas are deepened a minimum of 30 inches below lowest adjacent grade.
-A subdrain should be installed and connected to an appropriate outlet (e.g. storm drain catch basin). The subdrain should consist of a
minimum 4-inch perforated pipe (Schedule 40 PVC or similar), covered with washed ¾-inch gravel and wrapped in filter fabric
(Mirafi 140 N or equivalent).
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of
study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2
Result*
If all answers from row 1-4 are yes then partial infiltration design is potentially feasible.
The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
Partial Infiltration
*To be completed using gathered site information and best professional judgment considering the definition of MEP in the
MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings.
Aardvark Permeameter Data Analysis
Project Name:Date:2/8/2018
Project Number:By:LR
Borehole Location:Ref. EL (feet, MSL):42.0
Bottom EL (feet, MSL):41.8
Borehole Diameter, d (in.):4.25Borehole Depth, H (feet):2.00 Wetted Area, A (in2):89.68
Distance Between Reservoir & Top of Borehole (in.):29.00Depth to Water Table, s (feet):50.00Height APM Raised from Bottom (in.):2.00Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):46.25Head Height Calculated, h (in.):5.65Head Height Recorded, h (in.):5.50Distance Between Constant Head and Water Table, L (in.):581.65
Reading Time (min)Time Elapsed
(min)
Reservoir Water
Weight (g)
Resevoir Water
Weight (lbs)
Interval Water
Consumption (lbs)
Total Water
Consumption (lbs)
*Water
Consumption Rate
(in3/min)
1 0 17.625
2 5 5.00 17.605 0.020 0.020 0.111
3 10 5.00 17.575 0.030 0.050 0.166
4 15 5.00 17.570 0.005 0.055 0.028
5 20 5.00 17.560 0.010 0.065 0.055
6 25 5.00 17.555 0.005 0.070 0.028
7 30 5.00 17.550 0.005 0.075 0.028
8 35 5.00 17.545 0.005 0.080 0.028
9 40 5.00 17.540 0.005 0.085 0.028
10
111213
14
15
16
17
18
19
20
21
22
23
242526
27
28
0.028
Field-Saturated Hydraulic Conductivity (Infiltration Rate)
Case 1: L/h > 3 K sat =1.40E-04 in/min 0.008 in/hr
2690 Roosevelt Street
G2245-52-01
P-1
Steady Flow Rate, Q (in3/min):
0.0
0.1
0.1
0.2
0.2
0 5 10 15 20 25 30 35 40 45Wa
t
e
r
C
o
n
s
u
m
p
t
i
o
n
Ra
t
e
(
i
n
3/m
i
n
)
Time (min)
Aardvark Permeameter Data Analysis
Project Name:Date:2/8/2018
Project Number:By:LR
Borehole Location:Ref. EL (feet, MSL):41.0
Bottom EL (feet, MSL):40.8
Borehole Diameter, d (in.):4.25Borehole Depth, H (feet):2.00 Wetted Area, A (in2):102.94
Distance Between Reservoir & Top of Borehole (in.):28.00Depth to Water Table, s (feet):50.00Height APM Raised from Bottom (in.):3.00Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):44.25Head Height Calculated, h (in.):6.65Head Height Recorded, h (in.):6.50Distance Between Constant Head and Water Table, L (in.):582.65
Reading Time (min)Time Elapsed
(min)
Reservoir Water
Weight (g)
Resevoir Water
Weight (lbs)
Interval Water
Consumption (lbs)
Total Water
Consumption (lbs)
*Water
Consumption Rate
(in3/min)
1 1 16.875
2 6 5.00 16.734 0.141 0.141 0.779
3 11 5.00 16.609 0.126 0.266 0.696
4 16 5.00 16.473 0.136 0.402 0.751
5 21 5.00 16.337 0.136 0.538 0.751
6 26 5.00 16.201 0.136 0.674 0.751
7 31 5.00 16.066 0.136 0.809 0.751
8 36 5.00 15.930 0.136 0.945 0.751
9
10
111213
14
15
16
17
18
19
20
21
22
23
242526
27
28
0.751
Field-Saturated Hydraulic Conductivity (Infiltration Rate)
Case 1: L/h > 3 K sat =3.05E-03 in/min 0.183 in/hr
2690 Roosevelt Street
G2245-52-01
P-2
Steady Flow Rate, Q (in3/min):
0.0
0.2
0.4
0.6
0.8
1.0
0 5 10 15 20 25 30 35 40Wa
t
e
r
C
o
n
s
u
m
p
t
i
o
n
Ra
t
e
(
i
n
3/m
i
n
)
Time (min)
Project No. G2245-52-02 May 13, 2022
Roosevelt Nine LLC 2033 San Elijo Avenue, Suite 423 Cardiff, California 92014
Attention: Mr. Randolf Cherewick
Subject: UPDATE GEOTECHNICAL LETTER 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated December 18, 2019 (Project No. G2245-52-01).
3. Storm Water Management Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated April 21, 2020 (Project No. G2245-52-01).
Dear Mr. Cherewick:
In accordance with your request, we prepared this update letter regarding the existing referenced
geotechnical documents for the subject project. Based on our review of the project plans and our
reports and letters, our recommendations remain applicable to the design and construction of the
planned development and improvements.
We understand that the driveway will be designed using permeable pavers with a subdrain. This is
acceptable from a geotechnical engineering standpoint as shown on the current grading plans. We will
evaluate the pavement thickness required based on R-Values from the subgrade soil subsequent to the
grading operations.
Should you have any questions regarding this report, or if we may be of further service, please contact
the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Shawn Foy WeedonGE 2714
SFW:am
(e-mail) Addressee
Project No. G2245-52-02
August 12, 2022
Roosevelt Nine LLC
2033 San Elijo Avenue, Suite 423
Cardiff, California 92014
Attention: Mr. Randolf Cherewick
Subject: UPDATE GEOTECHNICAL LETTER
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared
by Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad,
California, prepared by Geocon Incorporated, dated December 18, 2019 (Project
No. G2245-52-01).
3. Storm Water Management Investigation, 2690 Roosevelt Street, Carlsbad,
California, prepared by Geocon Incorporated, dated April 21, 2020 (Project
No. G2245-52-01).
4. Grading Plans for The Roosevelt, by Civil Landworks, dated June 23, 2022
(Project No. CT2019-0006)
Dear Mr. Cherewick:
In accordance with your request, we prepared this update letter regarding the existing referenced
geotechnical documents for the subject project. Based on our review of the project plans and our
reports and letters, our recommendations remain applicable to the design and construction of the
planned development and improvements.
We understand that the driveway will be designed using permeable pavers with a subdrain.
Additionally, we understand that permeable pavers will be utilized in some of the rear patios and
walkways. In the areas where the permeable pavers are proposed, the exterior footings will be
deepened approximately 30 inches below grade, subgrade sloped 5% away from the building and a
subdrain system will be installed. This is acceptable from a geotechnical engineering standpoint as
shown on the current grading plans. We will evaluate the pavement thickness required based on R-
Values from the subgrade soil subsequent to the grading operations.
Geocon Project No. G2245-52-02 - 2 - August 12, 2022
Should you have any questions regarding this report, or if we may be of further service, please contact
the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Dylan Thomas
PG
Shawn Foy Weedon
GE 2714
DT:SFW:am
(e-mail) Addressee
Project No. G2245-52-02 August 24, 2022
Roosevelt Nine LLC 2033 San Elijo Avenue, Suite 423 Cardiff, California 92014
Attention: Mr. Randolf Cherewick
Subject: STRUCTURAL PLAN REVIEW THE ROOSEVELT 2690 ROOSEVELT STREET CARLSBAD , CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated December 18, 2019 (Project No. G2245-52-01).
3. Structural Plans, Framing and Foundation Details, Proposed Residence, 2690 Roosevelt Street, Carlsbad, California, prepared by Lucia Engineering Inc., dated August 8, 2022
Dear Mr. Cherewick:
In accordance with the request of Paul Nong with Civil Landworks, we reviewed the referenced structural plans for the subject development. Based on our review of the project plans, we opine the plans and details have been prepared in substantial conformance with the recommendations presented in the referenced geotechnical report.
We limited our review to geotechnical aspects of project development and the review did not include other details on the referenced plans. Geocon Incorporated has no opinion regarding other details found on the referenced plans, structural or otherwise, that do not directly pertain to geotechnical aspects of site development.
If you have any questions regarding this correspondence, or if we may be of further service, please contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Shawn Foy Weedon
GE 2714
Dylan ThomasPG 9857
SFW:DT:am
(e-mail) Addressee
Project No. G2245-52-02
May 20, 2022
Roosevelt Nine LLC
2033 San Elijo Drive, Suite 423
Cardiff, California 92007
Attention: Mr. Randolf Cherewick
Subject: RESPONSE TO THIRD-PARTY GEOTECHNICAL REVIEW COMMENTS
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared
by Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated December 18, 2019 (Project No. G2245-52-01).
3. Storm Water Management Letter, 2690 Roosevelt Street, Carlsbad, California,prepared by Geocon Incorporated, dated April 21, 2020 (Project No. G2245-52-01).
4. Civil Plan Set, The Roosevelt, Carlsbad, California, prepared by Civil
Landworks dated March 14, 2022.
5. Third- Party Geotechnical Review (First), 2690 Roosevelt, Carlsbad, California,
GR2022-0013 prepared by Heatherington Engineering for City of Carlsbad,
dated April 11, 2022 (Project No. 9660.1, Log No. 21833).
Dear Mr. Cherewick:
We prepared this letter to address the referenced review comments prepared by Heatherington
Engineering dated April 11, 2022. The review comments are listed herein with the responses
immediately following.
Comment 1:Due to the age of the geotechnical investigation, the consultant should update the
grading and foundation recommendations with the requirements of the 2019
California Building Code and ASCE 7-16.
Response:We prepared the referenced letter titled Updated Geotechnical Recommendations
dated December 18, 2019 that provided updated seismic design criteria using the
2019 California Building Code and ASCE 7-16. The grading and foundation
recommendations in the referenced geotechnical investigation remain applicable to
Geocon Project No. G2445-52-02 - 2 - May 20, 2022
the design and construction of the planned development and are in accordance with
the 2019 California Building Code and ASCE 7-16.
Comment 2:The Consultant should review the project grading plans (reference 4), and
foundation plans, provide any additional geotechnical analyses/ recommendations
considered necessary, and confirm that the plans have been prepared in accordance
with the geotechnical recommendations.
Response:We will review the foundation plans and write a foundation plan review letter once
the foundation plans have been completed.
Comment 3:The Consultant should provide an updated description of proposed site grading and
construction.
Response:Grading should be consistent with our grading recommendations in our referenced
report dated April 8, 2019. Grading of the site should consist of excavating the
undocumented fill and placing properly compacted fill within the proposed
development areas. The building pad should be excavated such that at least 3 feet of
compacted fill exists below the planned structure. The undercuts should extend at
least 10 feet outside of the planned building envelope, where possible. The
excavations for the areas of the structures adjacent to the storm water devices should
be extended to at least 2 feet below the proposed foundations so the structure is
supported on compacted fill. The site should then be brought to final subgrade
elevations with fill compacted in layers. In general, soil native to the site is suitable
for use from a geotechnical engineering standpoint as fill if relatively free from
vegetation, debris and other deleterious material. Layers of fill should be about 6 to
8 inches in loose thickness and no thicker than will allow for adequate bonding and
compaction. Fill, including backfill and scarified ground surfaces, should be
compacted to a dry density of at least 90 percent of the laboratory maximum dry
density near to slightly above optimum moisture content in accordance with ASTM
Test Procedure D 1557. Fill materials placed below optimum moisture content may
require additional moisture conditioning prior to placing additional fill. The upper
12 inches of subgrade soil underlying pavement should be compacted to a dry
density of at least 95 percent of the laboratory maximum dry density near to slightly
above optimum moisture content shortly before paving operations.
Comment 4:Foundation and slab design criteria for expansive soils should be consistent with
Section 1808.6 of the 2019 California Building Code. The Consultant should update
foundation recommendations, as necessary.
Response:The recommendations for foundation and slab design criteria in our referenced
Geotechnical Investigation Report remain applicable with section 1808.6 of the
2019 California Building Code.
Comment 5:The Consultant should address expected total and differential settlement due to
grading and foundation loads.
Response:Due to proposed grading and foundation loads we calculated an estimated total and
differential (in 40 feet) settlement of about ½ inch based on a 6-foot square footing
bearing in compacted fill.
Comment 6:The Consultant should provide a list of recommended observation and testing
during site grading and construction.
Geocon Project No. G2445-52-02 - 3 - May 20, 2022
Response:Table 1 presents a list of recommended geotechnical observations we would expect
for the proposed development.
TABLE 1
EXPECTED GEOTECHNICAL TESTING AND OBSERVATION SERVICES
Construction Phase Observations Expected Time Frame
Grading
Base of Removal Part Time During
Removals
Geologic Logging Part Time to Full Time
Fill Placement and Soil Compaction Full Time
Foundations Foundation Excavation
Observations Part Time
Utility Backfill Fill Placement and Soil Compaction Part Time to Full Time
Retaining Wall
Backfill Fill Placement and Soil Compaction Part Time to Full Time
Subgrade for
Sidewalks,
Curb/Gutter and
Pavement
Soil Compaction Part Time
Pavement
Construction
Base Placement and Compaction Part Time
Asphalt Concrete Placement and
Compaction Full Time
Comment 1 Civil Plans:
Weep holes on retaining walls along the southern lot is asked to be removed, but
approved in discretionary. City comment that Geotech report state no weep holes.
However, upon reading the Geotech report, it states weep holes should not be used
where the seepage could be a nuisance or adversely affect the property adjacent to the
base of the wall. We recommend having Geotech review the plan and compose a letter
to clarify if weep holes are to be used in that area or not.
Response:Drainage openings through the base of the wall (weep holes) should not be used
where the seepage could be a nuisance or otherwise adversely affect the property
adjacent to the base of the wall. If weep holes are desired, the project civil engineer
will have to design to have nuisance water drain freely through weep holes at the face
of the wall. Weep holes may be used if the seepage will not adversely affect the
property. The Typical Retaining Wall Drainage Detail shown below should be used in
lieu of weep holes. The recommendations for retaining walls assume a properly
compacted granular (EI of 90 or less) free-draining backfill material with no
hydrostatic forces or imposed surcharge load.
Geocon Project No. G2445-52-02 - 4 - May 20, 2022
Typical Retaining Wall Drainage Detail
Should you have questions regarding this letter, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Dylan Thomas
PG 9857
Shawn Foy Weedon
GE 2714
DT:SFW:arm
(e-mail) Addressee
Project No. G2245-52-02
August 26, 2022
Roosevelt Nine LLC
2033 San Elijo Drive, Suite 423
Cardiff, California 92007
Attention: Mr. Randolf Cherewick
Subject: RESPONSE TO THIRD-PARTY GEOTECHNICAL REVIEW COMMENTS
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by
Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated December 18, 2019 (Project No. G2245-52-01).
3. Storm Water Management Letter, 2690 Roosevelt Street, Carlsbad, California,prepared by Geocon Incorporated, dated April 21, 2020 (Project No. G2245-52-01).
4. Civil Plan Set, The Roosevelt, Carlsbad, California, prepared by Civil Landworks
dated March 14, 2022.
5. Geotechnical Report Review (2nd), 2690 Roosevelt, Carlsbad, California,
GR2022-0013 prepared by the City of Carlsbad, dated August 19, 2022 (Permit
ID CT2019-0006, Grading Permit GR 2022-0013).
Dear Mr. Cherewick:
We prepared this letter to address the referenced review comments prepared by the City of Carlsbad
dated August 19, 2022. The review comments are listed herein with the responses immediately
following.
Comment 1:Foundation and design criteria for expansive soils should be consistent with Section
1808.6 of the 2019 California Building Code. The consultant should update
foundation recommendations as necessary. (repeat comment- the text of the report
(page 8) indicates the majority of the soil encountered possess a “Very Low” to
“High” expansion potential (EI of 130 or less). As soils with expansion index (EI)
over 20 are considered expansive and require mitigation in accordance with Sections
1803.5.3 and 1808.6 of the 2019 CBC, please provide the methods that are being
recommended to address expansive soils (for soils with an EI between 20 and 130)
Geocon Project No. G2245-52-02 - 2 - August 26, 2022
and provide a statement that the foundation system for the proposed structures will
meet the requirements of Section 1808.6 of the 2019 California Building Code.)
Response:The foundation recommendations in the referenced geotechnical investigation remain
applicable to the design and construction and are in accordance with section 1808.6
of the 2019 California Building Code. The foundation recommendations provided in
the referenced geotechnical documents incorporate and expansion index of 130 or
less in the design values. We will provide additional expansion index laboratory
testing during the grading for the proposed buildings and improvements.
Should you have questions regarding this letter, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Dylan Thomas
PG 9857
Shawn Foy Weedon
GE 2714
DT:SFW:arm
(e-mail) Addressee
GROCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL MATERIALSO
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159
Project No. G2245-52-02
September 30, 2022
Roosevelt Nine LLC
2033 San Elijo Drive, Suite 423
Cardiff, California 92007
Attention: Mr. Randolf Cherewick
Subject: RESPONSE TO THIRD-PARTY GEOTECHNICAL REVIEW COMMENTS
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by
Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad,
California, prepared by Geocon Incorporated, dated December 18, 2019 (Project
No. G2245-52-01). 3. Storm Water Management Letter, 2690 Roosevelt Street, Carlsbad, California,
prepared by Geocon Incorporated, dated April 21, 2020 (Project No. G2245-52-01).
4. Civil Plan Set, The Roosevelt, Carlsbad, California, prepared by Civil Landworks
dated March 14, 2022.
5. Geotechnical Report Review (2nd), 2690 Roosevelt, Carlsbad, California,
GR2022-0013 prepared by the City of Carlsbad, dated August 19, 2022 (Permit
ID CT2019-0006, Grading Permit GR 2022-0013).
6. Geotechnical Report Review Comments (3rd), 2690 Roosevelt, Carlsbad,
California, GR2022-0013 prepared by the City of Carlsbad, dated September 13,
2022 (Permit ID CT2019-0006, Grading Permit GR 2022-0013).
Dear Mr. Cherewick:
We prepared this letter to address the referenced review comments prepared by the City of Carlsbad
dated September 13, 2022. The review comments are listed herein with the responses immediately
following.
Comment 1: Foundation and design criteria for expansive soils should be consistent with Section
1808.6 of the 2019 California Building Code. The consultant should update
foundation recommendations as necessary. (repeat comment- the text of the report
(page 8) indicates the majority of the soil encountered possess a “Very Low” to
“High” expansion potential (EI of 130 or less). As soils with expansion index (EI)
Geocon Project No. G2245-52-02 - 2 - September 30, 2022
over 20 are considered expansive and require mitigation in accordance with Sections
1803.5.3 and 1808.6 of the 2019 CBC, please provide the methods that are being
recommended to address expansive soils (for soils with an EI between 20 and 130)
and provide a statement that the foundation system for the proposed structures will
meet the requirements of Section 1808.6 of the 2019 California Building Code.)A
recommendation for foundation/slab design provided in the geotechnical report
appears to be for conventional slab on-grade foundation systems( sections 7.6.1-7.6.4
and 7.7 of the “Geotechnical Investigation…”. Section 1808.6.2 of the 2019 CBC
requires that slabs on-grade constructed on expansive soils be designed in
accordance with WRI/CRSI Design of Slab on-Ground Foundations or a post-
tensioned designed in accordance with PTI DC 10.5. As an Effective Plasticity Index
has not been provided reviewer is requesting that the consultant state the specific
procedure of Section 1808.6.2 of the 2019 CBC that is being applied in the foundation
and slab on-grade recommendations to address an expansion index up to 130 and
satisfy the code requirement and mitigate potential expansive soils. Please indicate
the specific procedure of 1808.6.2 and provide justification on how the
recommendations in the geotechnical report are satisfying Section 1808.6.2 for slabs-
on grade. Please provide the necessary geotechnical parameters (effective Plasticity
Index, etc.) for WRI/CRSI design or indicate the use of a post-tensioned design in
accordance with PTI DC 10.5 to satisfy Section 1808.6.2; or state one of the other
methods of Section1808.6 (1808.6.3 or 1808.6.4 are being issued to satisfy the code
requirement and provide recommendations accordingly.
Response: The foundation recommendations in the referenced geotechnical investigation remain
applicable to the design and construction and are in accordance with section 1808.6
of the 2019 California Building Code. The foundation recommendations provided in
the referenced geotechnical documents incorporate and expansion index of 130 or
less in the design values. We will provide additional expansion index laboratory
testing during the grading for the proposed buildings and improvements. In
accordance with 2019 CBC, section 1808.6.4 in lieu of designing foundations in
accordance with 1808.6.1 and 1808.6.2. the active zone of expansive soils will be
stabilized by presaturation. This will be achieved during the grading operation when
the building will be undercut so that a minimum of 3 feet of moisture conditioned
compacted fill exist below the proposed structure.
Should you have questions regarding this letter, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Dylan Thomas
PG 9857
Shawn Foy Weedon
GE 2714
DT:SFW:arm
(e-mail) Addressee
Project No. G2245-52-02
December 8, 2022
Roosevelt Nine LLC
2033 San Elijo Drive, Suite 423
Cardiff, California 92007
Attention: Mr. Randolf Cherewick
Subject: RESPONSE TO THIRD-PARTY GEOTECHNICAL REVIEW COMMENTS
2690 ROOSEVELT STREET
CARLSBAD, CALIFORNIA
Dear Mr. Cherewick:
We prepared this letter to address the referenced structural review comments prepared by True North
Compliance Services dated November 30, 2022. The review comments are listed herein with the
responses immediately following.
Comment (General) S1: Soil report 18: Check the applies seismic earth load based on PGAm of 0.57
based on ASCE 7-16. 11/30/2022-PC2: Not Resolved. The seismic
parameters in the soil report must be changed to comply with ASCE7-16.
Response:We prepared the referenced letter titled Updated Geotechnical
Recommendations dated December 18, 2019 that provided updated seismic
design criteria using the 2019 California Building Code and ASCE 7-16. The
grading and foundation recommendations in the referenced geotechnical
investigation remain applicable to the design and construction of the planned
development and are in accordance with the 2019 California Building Code
and ASCE 7-16.
Comment (Plans) S2: All sheets of the plans shall be signed and stamped by the engineer of record.
11/30/2022-PC2: Sheet 9 of 10 shall be signed and stamped by the responsible
engineer.
Response:We prepared the referenced letter titled Structural Plan Review Letter dated
August 24, 2022 that indicates that we reviewed the referenced structural plans
and that the structural plans have been prepared in substantial conformance
with the recommendations presented in the referenced geotechnical reports
and letters. Based on discussions with the City of Carlsbad, we understand the
referenced structural plan review letter will satisfy the city’s requirements.
Comment (Plans) S3: Foundation walls shall be signed reviewed and approved with no exceptions
by the soil engineer. 11/30/2022-PC2: Not resolved.
Geocon Project No. G2445-52-02 - 2 - December 8, 2022
Response:We prepared the referenced letter titled Structural Plan Review Letter dated
August 24, 2022 that states we reviewed the foundation plans in the
referenced structural plans and that the structural plans have been prepared in
substantial conformance with the recommendations presented in the
referenced geotechnical reports and letters. Based on discussions with the
City of Carlsbad, we understand the referenced structural plan review letter
will satisfy the city’s requirements.
Should you have questions regarding this letter, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Dylan Thomas
PG 9857
Shawn Foy Weedon
GE 2714
DT:SFW:arm
(e-mail) Addressee
Geocon Project No. G2445-52-02 - 3 - December 8, 2022
LIST OF REFERENCES
1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon
Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated December 18, 2019 (Project No. G2245-52-01).
3. Structural Plan Review, The Roosevelt, 2960 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated August 24, 2022 (Project No. G2245-52-02)
4. Civil Plan Set, The Roosevelt, Carlsbad, California, prepared by Civil Landworks dated
December 6. 2022.
5. Structural Plans, Framing and Foundation Details, Proposed Residence, 2690 Roosevelt Street,
Carlsbad, California, prepared by Lucia Engineering Inc., dated August 8, 2022
6. Third-Party Geotechnical Review (Second Review), Transmittal Letter, Roosevelt Condos-
Perimeter Walls,2690 Roosevelt, Carlsbad, California, GR2022-0013 prepared by True North
Compliance Services for City of Carlsbad, dated November 30, 2022 (City Permit
No. PC2022-0044, True North No. 22-018-240).
Project No. G2245-52-02 January 10, 2023
Roosevelt Nine LLC 2033 San Elijo Avenue, Suite 423 Cardiff, California 92014
Attention: Mr. Randolf Cherewick
Subject: STRUCTURAL PLAN REVIEW THE ROOSEVELT 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated April 8, 2019 (Project No. G2245-52-01).
2. Update Geotechnical Recommendations, 2690 Roosevelt Street, Carlsbad, California, prepared by Geocon Incorporated, dated December 18, 2019 (Project No. G2245-52-01).
3. Revised Structural Plans, Retaining Walls, The Roosevelt, 2690 Roosevelt Street, Carlsbad, California, prepared by Lucia Engineering Inc., dated January 10, 2023.
Dear Mr. Cherewick:
In accordance with the request of Paul Nong with Civil Landworks, we reviewed the referenced structural retaining wall plans for the subject development. Based on our review of the project plans, we opine the plans and details have been prepared in substantial conformance with the recommendations presented in the referenced geotechnical report.
We limited our review to geotechnical aspects of project development and the review did not include other details on the referenced plans. Geocon Incorporated has no opinion regarding other details found on the referenced plans, structural or otherwise, that do not directly pertain to geotechnical aspects of site development.
If you have any questions regarding this correspondence, or if we may be of further service, please contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Shawn Foy Weedon
GE 2714
Dylan ThomasPG 9857
SFW:DT:am
(e-mail) Addressee