HomeMy WebLinkAboutDEV 2017-0030; 906 PINE AVENUE; GEOTECHNICAL EVALUATION; 2016-08-12GEOTECHNICAL EVALUATION FOR
PROPOSED CONSTRUCTION AT 906 PINE AVENUE
W.O. 7099-A-SC AUGUST 12, 2016
RECEIVED
AUG 23 Viii
LAND DEVELOPMENT
ENGINEERING
1tV70 rr-ii1
Geotechnical. Geologic. Coastal. Environmental
5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760) 931-0915 • www.geosoilsinc.com
August 12, 2016
W.O. 7099-A-SC
Mr. Richard Smerud
906 Pine Avenue
Carlsbad, California 92014
Subject: Geotechnical Evaluation for Proposed Construction at 906 Pine Avenue,
Carlsbad, San Diego County, California
Dear Mr. Smerud:
In accordance with your request and authorization, GeoSoils, Inc. (GSI) is pleased to
present the results of our preliminary geotechnical evaluation at the subject site. The
purpose of our study was to evaluate the geologic and geotechnical conditions at the site,
in order to develop preliminary recommendations for site earthwork and the design of
foundations and pavements related to the proposed multi-family residential construction
at the property.
EXECUTIVE SUMMARY
Based upon our field exploration, geologic, and geotechnical engineering analysis, the
proposed development appears feasible from a soils engineering and geologic viewpoint,
provided that the recommendations presented in the text of this report are properly
incorporated into the design and construction of the project. The most significant elements
of our study are summarized below:
In general, the site may be characterized as an existing, developed site, underlain
by colluvium (topsoils) soils developed on Quaternary-age, older paralic deposits,
with Tertiary-age sediments at a depth of about 14 feet below existing grade.
Due to their relatively low density and lack of uniformity, all surficial deposits of
colluvium, and near surface, weathered older paralic deposits are considered
unsuitable for the support of settlement-sensitive improvements (i.e., residential
foundations, concrete slab-on-grade floors, site walls, exterior hardscape, etc.)
and/or engineered fill in their existing state. Based on the available data, the
thickness of these soils across the site is anticipated to vary between approximately
2 to 3 feet. However, localized thicker sections of unsuitable soils cannot be
precluded, and should be anticipated. Conversely, the underlying unweathered
older paralic deposits are generally considered suitable for the support of
settlement-sensitive improvements and/or engineered fill.
It should be noted that the 2013 California Building Code ([2013 CBC], California
Building Standards Commission [CBSC], 2013) indicates that removals of
unsuitable soils be performed across all areas to be graded, under the purview of
the grading permit, not just within the influence of the residential structure.
Relatively deep removals may also necessitate a special zone of consideration, on
perimeter/confining areas. This zone would be approximately equal to the depth
of removals, if removals cannot be performed onsite or offsite. Thus, any
settlement-sensitive improvements (walls, curbs, flatwork, etc.), constructed within
this zone may require deepened foundations, reinforcement, etc., or will retain some
potential for settlement and associated distress. This will also require proper
disclosure to any owners and all interested/affected parties should this condition
exist at the conclusion of grading.
Expansion Index (El.), and Plasticity Index (P.1.) testing performed on a
representative sample of the onsite soil indicates an E.I. of less than 20 (very low
expansive), and non plastic soil conditions. As such, site soils are considered
non-detrimentally expansive and no specific foundation design appears necessary
to mitigate expansive soil effects, on a preliminary basis. Soil expansion should be
re-evaluated at the conclusion of grading.
Laboratory testing indicates that site soils are relatively acidic to neutral with respect
to pH, moderately corrosive to exposed buried metals when saturated, present
negligible sulfate exposure to concrete and somewhat elevated for chloride
exposure. Site soils are classified as "Exposure Class Cl." Corrosion testing at the
completion of grading is recommended in order to obtain actual corrosion data
specific to design grades.
Foundations should be minimally designed to accommodate a differential
settlement of 1 inch in 40 feet (1/480) or between dissimilarly loaded foundation
elements without distress.
A regional groundwater table was not encountered during our subsurface studies
to the depth explored, however a perched groundwater table was observed along
and near the contact between paralic deposits and the underlying
Santiago Formation. As such, regional groundwater is not anticipated to
significantly affect the planned improvements. Additional perched water may occur
in the future along zones of contrasting permeability and/or density. This potential
should be disclosed to all interested/affected parties.
Our evaluation indicates there are no known active faults crossing the site and the
natural slope upon which the site is located, and the site has a very low
susceptibility to deep-seated landslides. Owing to the depth to groundwater and
the dense nature of the terrace (paralic) deposits, the potential for the site to be
adversely affected by liquefaction is considered very low. Site soils are considered
erosive. Thus, properly designed site drainage is necessary in reducing erosion
damage to the planned improvements.
Richard Smerud W.O. 7099-A-SC
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The seismic acceleration values and design parameters provided herein should be
considered during the design of the proposed development. The adverse effects
of seismic shaking on the structure(s) will likely be wall cracks, some
foundation/slab distress, and some seismic settlement. However, it is anticipated
that the structure will be repairable in the event of the design seismic event. This
potential should be disclosed to any owners and all interested/affected parties.
Additional adverse geologic features that would preclude project feasibility were not
encountered, based on the available data.
The recommendations presented in this report should be incorporated into the
design and construction considerations of the project.
The opportunity to be of service is sincerely appreciated. If you should have any
questions, please do not hesitate to contact our office.
Respectfully subm
GeoSoils, Inc. I Url
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Robert G. Crisman
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Engineering Geologist, CEG 1934
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Richard Smerud W.O. 7099-A-SC
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TABLE OF CONTENTS
SCOPE OF SERVICES ....................................................1
SITE DESCRIPTION AND PROPOSED DEVELOPMENT .........................1
FIELD STUDIES .........................................................3
REGIONAL GEOLOGY ...................................................3
SITE GEOLOGIC UNITS ..................................................5
General..........................................................5
Colluvium/Fill - Undifferentiated (Not Mapped) .....................5
Quaternary Older Paralic Deposits (Map Symbol - Qop6.7) ............5
Tertiary Santiago Formation (Map Symbol - Tsa) ...................5
Structural Geology .................................................6
GROUNDWATER ........................................................6
GEOLOGIC HAZARDS EVALUATION ........................................6
Mass Wasting/Landslide Susceptibility .................................6
FAULTING AND REGIONAL SEISMICITY .....................................7
RegionalFaults ....................................................7
Local Faulting .....................................................7
Seismicity........................................................7
Seismic Shaking Parameters .........................................8
SECONDARY SEISMIC HAZARDS ..........................................9
SLOPE STABILITY ......................................................10
LABORATORY TESTING .................................................10
Classification .....................................................10
Moisture-Density Relations .........................................10
Expansion Index ..................................................10
Atterberg Limits ...................................................11
Consolidation Test ................................................11
Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides .............11
Corrosion Summary .........................................11
PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS ....................12
EARTHWORK CONSTRUCTION RECOMMENDATIONS .......................14
General.........................................................14
Demolition/Grubbing ..............................................14
Treatment of Existing Ground .......................................15
Ge0$oils, Inc.
Fill Suitability . 15
Fill Placement ....................................................16
Graded Slopes ...................................................16
Temporary Slopes ................................................16
PRELIMINARY RECOMMENDATIONS - FOUNDATIONS .......................16
General.........................................................16
Preliminary Foundation Design ......................................17
PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS ...........18
Foundation Settlement .............................................19
SOIL MOISTURE TRANSMISSION CONSIDERATIONS ........................19
DRIVEWAY/PARKING, FLATWORK, AND OTHER IMPROVEMENTS ..............22
DEVELOPMENT CRITERIA ...............................................24
Onsite Storm Water Treatment ......................................24
Slope Maintenance and Planting .....................................25
Drainage........................................................25
ErosionControl ...................................................26
Landscape Maintenance ...........................................26
Gutters and Downspouts ............................................26
Subsurface and Surface Water ......................................27
Site Improvements ................................................27
Tile Flooring .....................................................27
Additional Grading ................................................27
Footing Trench Excavation .........................................27
Trenching/Temporary Construction Backcuts ..........................28
Utility Trench Backfill ..............................................28
SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND
TESTING.........................................................29
OTHER DESIGN PROFESSIONALS/CONSULTANTS ..........................29
PLANREVIEW .........................................................30
LIMITATIONS ..........................................................31
FIGURES:
Figure 1 - Site Location Map .........................................2
Figure 2 - Geotechnical Map .........................................4
Richard Smerud Table of Contents
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ATTACHMENTS:
Appendix A - References ...................................
Appendix B - Hand Auger Boring Logs ........................
Appendix C - Seismicity ....................................
Appendix D - Laboratory Results .............................
Appendix E - General Earthwork and Grading Guidelines .........
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Richard Smerud Table of Contents
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GEOTECHNICAL EVALUATION FOR
PROPOSED CONSTRUCTION AT 906 PINE AVENUE
CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA
SCOPE OF SERVICES
The scope of our services has included the following:
Review of readily available published literature, aerial photographs, and maps of the
vicinity (see Appendix A), including proprietary in-house geolog ic/geotechnical
reports for other nearby sites.
Site reconnaissance mapping and the excavation of two (2) rig mounted exploratory
hollow-stem-auger borings to evaluate the soil/formation profiles, sample
representative earth materials, and delineate the horizontal and vertical extent of
earth material units (see Appendix B).
General areal seismicity evaluation (see Appendix C).
Appropriate laboratory testing of relatively undisturbed and representative bulk soil
samples collected during our geologic mapping and subsurface exploration
program.
Analysis of field and laboratory data relative to the proposed development.
Appropriate engineering and geologic analyses of data collected, and the
preparation of this summary report and accompaniments.
SITE DESCRIPTION AND PROPOSED DEVELOPMENT
The subject site consists of a rectangular corner lot property in the City of Carlsbad,
San Diego County, California (see Site Location Map, Figure 1). The property is bounded
by Pine Avenue to the southeast, Harding Street to the southwest, and existing residential
property on all remaining sides. Access to subject property is via the property's driveway
from Harding Street. The site appears to be at an approximate elevation of 65 feet to
69 feet above Mean Sea Level (MSL) (Google, 2016). Drainage appears to be generally
directed offsite to the south, toward the intersection of Harding Street and Pine Avenue.
Vegetation onsite consists of typical residential landscaping.
It is anticipated that the existing residential structure is to be removed, and the site
prepared for construction of a multi-family residential structure. The proposed
development will be a three-story residential complex, where the first (ground floor)
consisting of garage/storage areas, and bedrooms for superjacent dwellings. The second
and third floors will consist of bedrooms, living areas, and decks. Basements are not
proposed.
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GSI anticipates that the construction would consist of wood frame with typical foundations
and slab-on-grade ground floors. Building loads are assumed to be typical for this type
of relatively light construction. Sewage disposal is anticipated to be connected into the
regional, municipal system. Storm water may be treated onsite prior to its delivery into the
municipal system.
FIELD STUDIES
Site-specific field studies were conducted by GSI during June 2016, and consisted of
reconnaissance geologic mapping and the excavation of two (2) exploratory borings with
a hollow-stem-auger drilling rig, for an evaluation of near-surface soil and geologic
conditions onsite. The hollow-stem-auger borings were logged by a representative of this
office who collected representative bulk and relatively undisturbed soil samples for
appropriate laboratory testing. The logs of the hollow-stem-auger borings are presented
in Appendix B. The approximate location of the borings are presented on the Geotechnical
Map (see Figure 2). Figure 2 uses a Google Earth image as a base map.
REGIONAL GEOLOGY
The subject property lies within the coastal plain physiographic region of the Peninsular
Ranges Geomorphic Province of southern California. This region consists of dissected,
mesa-like terraces that transition inland to rolling hills. The encompassing Peninsular
Ranges Geomorphic Province is characterized as elongated mountain ranges and valleys
that trend northwesterly. This geomorphic province extends from the base of the east-west
aligned Santa Monica - San Gabriel Mountains, and continues south into Baja California.
The mountain ranges within this province are underlain by basement rocks consisting of
pre-Cretaceous metased imentary rocks, Jurassic metavolcan ic rocks, and Cretaceous
plutonic (granitic) rocks.
In the Southern California region, deposition occurred during the Cretaceous Period and
Cenozoic Era in the continental margin of a forearc basin. Sediments, derived from
Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited during the
Tertiary Period (Eocene-age) into the narrow, steep, coastal plain and continental margin
of the basin. These rocks have been uplifted, eroded, and deeply incised. During early
Pleistocene time, a broad coastal plain was developed from the deposition of marine
terrace deposits. During mid to late Pleistocene time, this plain was uplifted, eroded and
incised. Alluvial deposits have since filled the lower valleys, and young marine sediments
are currently being deposited/eroded within coastal and beach areas. Regional geologic
mapping by Kennedy and Tan (2007) indicate the site is underlain by Quaternary-age older
paralic deposits (formally known as "terrace deposits"), which is considered bedrock, or
formational sediments, at the site. Older deposits of Eocene-age sedimentary bedrock
underlie the site at depth.
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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QOP
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APPROXIMATE LOCA lION OF
SDY AREA /PROPTY I/NE
ALL LOCATIONS ARE
APPROXIMATE
This document or efile is not a part of the AIM Construction Documents and should not
be relied upon as being an accurate VuL
depiction of design. GRAPH/C SCALE
20 0 10 20 40
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GSI LEGEND i" = 20'
- APPROXIMATE LOCATION OF
HAND—AUGER BORING
QOP 67— DQEUPAOTEARYAGE OLDER PARALIC SITS GEO TECHNICAL MAP
T - TERTIARY—AGE SANTIAGO FORMATION, Figure 2
CIRCLED WERE BURIED WO. 7099-A-SC DATE: 08116 SCALE: I"=20"
SITE GEOLOGIC UNITS
General
The earth material units that were observed and/or encountered at the subject site consist
of surficial deposits of undifferentiated colluvium, overlying Quaternary-age older paralic
deposits at shallow depth, which in turn overlie the Eocene-age Santiago Formation. A
general description of each material type is presented as follows, from youngest to oldest.
Colluvium/Fill - Undifferentiated (Not Mapped)
As observed, fill and colluvium (topsoil) occurs at the surface and generally consists of
dark reddish brown to strong brown, damp, loose to medium dense with depth, and
porous fine grained silty sand. Where encountered in our borings, the thickness of these
earth materials was on the order of about 2 feet thick. All colluvium is considered subject
to settlement under loading and therefore should be removed and reused as properly
engineered fill, in areas proposed for settlements-sensitive improvements.
Quaternary Older Paralic Deposits (Map Symbol - Qop67)
Quaternary-age older paralic deposits (terrace deposits) were observed underlying existing
colluvium at depths on the order of about 2 feet below existing grade. Where encountered,
these sediments generally exhibit a near surface weathered zone (about 1 foot thick),
consisting of dark reddish brown to strong brown, silty sand to a very fine-grained sand
with silt. The weathered older paralic deposits were generally damp and medium dense,
exhibited local porosity caused by organic roots. Paralic deposits (considered bedrock)
underlying the weathered zone, primarily consist of moist, medium dense, light yellowish
brown to red brown, silty sand. Weathered paralic deposits are considered potentially
compressible in their existing state and therefore should be removed and recompacted if
settlement-sensitive improvements and/or planned fills are proposed within their influence.
Paralic deposits below a depth of about 3 feet below existing grade are considered
suitable for support of proposed fills and settlement-sensitive improvements.
Tertiary Santiago Formation (Map Symbol - Tsa)
Older sedimentary bedrock, belonging to the Tertiary-age Santiago Formation, underlies
the paralic deposits these sediments were observed at depths on the order of 14 feet to
141/2 feet below the existing ground surface. Where encountered, these soils consist of
light yellow brown, sandstone with some scattered cobbles. Formational soils observed
are moist to wet, and dense to very dense. Formational soils are considered suitable for
the support of compacted fills and settlement-sensitive improvements.
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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Structural Geology
Bedding within older paralic deposits is generally flat lying to very gently dipping and
should not affect site development. The underlying contact with the Santiago Formation
appears relatively flat-lying, sloping about 1 degree to the west, and bedding within the
Santiago Formation dips about 5 to 8 degrees to the west.
GROUNDWATER
Regional groundwater is estimated to be generally within afew feet of sea level, and is not
anticipated to significantly affect proposed site development, provided that the
recommendations contained in this report are properly incorporated into final design and
construction. However, GSl did encounter a perched groundwater table (above or on the
Santiago Formation) at depths of about 14 feet and 141/2 feet below existing grade across
the site. These observations reflect site conditions at the time of our investigation and do
not preclude future changes in local groundwater conditions from excessive irrigation,
precipitation, or that were not obvious, at the time of our investigation.
Seeps, springs, or other indications of subsurface water were not noted on the subject
property during the time of our field investigation. However, perched water seepage may
occur locally (as the result of heavy precipitation and/or irrigation, or damaged wet utilities)
along zones of contrasting permeabilities/densities (colluvium/paralic deposit contacts,
sandy/clayey fill lifts, etc.) or along geologic discontinuities. This potential should be
anticipated and disclosed to all interested/affected parties.
Due to the potential for post-development perched water to manifest near the surface,
owing to as-graded permeability/density contrasts, more onerous slab design is necessary
for any new slab-on-grade floor (State of California, 2016). Recommendations for reducing
the amount of water and/or water vapor through slab-on-grade floors are provided in the
"Soil Moisture Considerations" sections of this report.
GEOLOGIC HAZARDS EVALUATION
Mass Wasting/Landslide Susceptibility
Due to the relatively flat lying condition of the site, and the nature of the underlying soils,
the site is not considered susceptible to significant mass wasting or landsliding. While
significant slopes are not anticipated, the onsite soils are considered erosive subject to
rilling, gullying, sloughing, etc. depending on rainfall severity and surface drainage. Such
risks can be minimized through properly designed and controlled surface drainage.
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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FAULTING AND REGIONAL SEISMICITY
Regional Faults
Our review indicates that there are no known active faults crossing the project and the site
is not within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). However,
the site is situated in an area of active faulting, as is all of Southern California. The Rose
Canyon fault is closest known active fault to the site (located at a distance of approximately
5.3 miles [8.5 kilometers]) and should have the greatest effect on the site in the form of
strong ground shaking, should the design earthquake occur. A list and the location of the
Rose Canyon fault and other major faults relative to the site is provided in Appendix C. The
possibility of ground acceleration, or shaking at the site, may be considered as
approximately similar to the southern California region as a whole.
Local Faulting
Although active faults lie within a few miles of the site, no local active faulting was noted
in our review, nor observed to specifically transect the site during the field investigation.
Additionally, a review of available regional geologic maps does not indicate the presence
of local active faults crossing the specific project site.
Seismicity
It is our understanding that site-specific seismic design criteria from the 2013 California
Building Code ([2013 CBC], California Building Standards Commission [CBSC], 2013), are
to be utilized for foundation design. Much of the 2013 CBC relies on the American Society
of Civil Engineers (ASCE) Minimum Design Loads for Buildings and Other Structures
(ASCE Standard 7-10). The seismic design parameters provided herein are based on the
2013 CBC.
The acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999) has been
incorporated into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed
by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using
digitized California faults as earthquake sources. The program estimates the closest
distance between each fault and a given site. If a fault is found to be within a user-selected
radius, the program estimates peak horizontal ground acceleration that may occur at the
site from an upper bound (formerly "maximum credible earthquake"), on that fault. Upper
bound refers to the maximum expected ground acceleration produced from a given fault.
Site acceleration (g) was computedby one user-selected acceleration-attenuation relation
that is contained in EQFAULT. Based on the EQFAULT program, a peak horizontal ground
acceleration from an upper bound event on the Rose Canyon fault may be on the order of
0.55 g. The computer printouts of pertinent portions of the EQFAULT program are
included within Appendix C.
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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Historical site seismicity was evaluated with the acceleration-attenuation relation of
Bozorgnia, Campbell, and Niazi (1999), and the computer program EQSEARCH
(Blake, 2000b, updated to January 2015). This program performs a search of the historical
earthquake records for magnitude 5.0 to 9.0 seismic events within a 100-kilometer radius,
between the years 1800 through January 2015. Based on the selected
acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated,
which may have affected the site during the specific event listed. Based on the available
data and the attenuation relationship used, the estimated maximum (peak) site
acceleration during the period 1800 through January 2015 was about 0.24 g. A historic
earthquake epicenter map and a seismic recurrence curve are also estimated/generated
from the historical data. Computer printouts of the EQSEARCH program are presented in
Appendix C.
Seismic Shaking Parameters
Based on the site conditions, the following table summarizes the updated site-specific
design criteria obtained from the 2013 CBC (CBSC, 2013), Chapter 16 Structural Design,
Section 1613, Earthquake Loads. The computer program "U.S. Seismic Design Maps,
provided by the United States Geologic Survey (USGS, 2014) was utilized for design
(http://geohazards.usgs.gov/designmaps/us/application.php). The short spectral response
utilizes a period of 0.2 seconds.
2013 CBC SEISMIC DESIGN PARAMETERS
PARAMETER VALUE 2013 CBC
REFERENCE
Risk Category I, II, or Ill Table 1604.5
Site Class D Section 1613.3.2/ASCE 7-10
(p. 203-205)
Spectral Response - (0.2 sec), S 1.145g Section 1613.3.1
Figure 1613.3.1 (1)
Spectral Response - (1 sec), S1 0.439g Section 1613.3.1
Figure 1613.3.1 (2)
Site Coefficient, F 1.042 Table 1613.3.3(1)
Site Coefficient, F 1.561 Table 1613.3.3(2)
Maximum Considered Earthquake Spectral 1.193g Section 1613.3.3
Response Acceleration (0.2 sec), SMS (Eqn 16-37)
Maximum Considered Earthquake Spectral 0.686g Section 1613.3.3
Response Acceleration (1 sec), SM, (Eqn 16-38)
5% Damped Design Spectral Response 0.795g Section 1613.3.4
Acceleration (0.2 sec), (Eqn 16-39)
5% Damped Design Spectral Response 0.457g Section 1613.3.4
Acceleration (1 sec), s0, (Eqn 16-40)
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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2013 CBC SEISMIC DESIGN PARAMETERS
- PARAMETER VALUE 2013 CBC
REFERENCE
PGA, (Probabilistic Vertical Ground Acceleration may be 0.474g ASCE 7-10 (Eqn 11.8.1) assumed as about 50% of this value)
Seismic Design Category '3 D Section 1613.3 .5IASCE 7-10
(Table 11.6-1 or 11.6-2)
GENERAL SEISMIC PARAMETERS
PARAMETER I VALUE
Distance to Seismic Source (Rose Canyon fault) 5.3 mi (8.5 km)"
Upper Bound Earthquake (Rose Canyon fault) M = 7.2(2)
'"- From Blake (2000a)
(2) - Cao, et al. (2003)
Conformance to the criteria above for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will not occur
in the event of a large earthquake. The primary goal of seismic design is to protect life, not
to eliminate all damage, since such design may be economically prohibitive. Cumulative
effects of seismic events are not addressed in the 2013 CBC (CBSC, 2013) and regular
maintenance and repair following locally significant seismic events (i.e., M5.5) will likely
be necessary, as is the case in all of southern California.
SECONDARY SEISMIC HAZARDS
The following list includes other geologic/seismic related hazards that have been
considered during our evaluation of the site. The hazards listed are considered negligible
and/or mitigated as a result of site location, soil characteristics, and typical site
development procedures:
Liquefaction
Lateral Spreading
Subsidence
Ground Lurching or Shallow Ground Rupture
Tsunami
Seiche
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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SLOPE STABILITY
Based on site conditions and planned improvements, significant cut and/or fill slopes are
not anticipated. Therefore, no recommendations are deemed necessary. Temporary
slopes for construction (i.e., trenching, etc.) are discussed in subsequent sections of our
report.
LABORATORY TESTING
Laboratory tests were performed on representative samples of site earth materials
collected during our subsurface exploration in order to evaluate their physical
characteristics. Test procedures used and results obtained are presented below.
Classification
Soils were visually classified with respect to the Unified Soil Classification System
(U.S.C.S.) in general accordance with ASTM D 2487 and D 2488. The soil classifications
of the onsite soils are provided on the Boring Logs in Appendix B.
Moisture-Density Relations
Field moisture content and dry unit weight were determined for relatively "undisturbed"
samples of earth materials. The dry unit weight was evaluated in general accordance with
ASTM D 2937, in pounds per cubic foot (pcf), and the field moisture content was evaluated
as a percentage of the dry weight. Water contents were measured in general accordance
with ASTM D 2216. The results of these tests are shown on the Boring Logs in Appendix B.
Expansion Index
Tests were performed on a representative soil sample obtained from Boring B-2
(composite sample) to evaluate expansion potential. Testing was performed in general
accordance with ASTM D 4829, and indicates a very low expansion potential (Expansion
Index [E.l.] = <5), where tested. The Expansion Index (E.l.) tests were performed in
general accordance with ASTM Standard D 4829. The laboratory test results are presented
in the following table:
I LOCATION I SOIL TYPE I EXPANSION INDEX I EXPANSION POTENTIAL I
I 6-2 @ 5171 I Silty Sand I 8 I Very Low I
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Atterberg Limits
A test was performed to evaluate the liquid limit, plastic limit, and plasticity index in general
accordance with ASTM D 4318. The test results are presented below and in Appendix D:
I LOCATION I LIQUID LIMIT 1. PLASTIC LIMIT I PLASTICITY INDEX'I I 8-2 @ 5' I 24 I 15 I 9 =
Consolidation Test
Consolidation tests were performed on a selected undisturbed sample. Testing was
performed in general accordance with ASTM Test Method D 2435. Test results are
presented as in Appendix D. The testing indicated that the samples collapsed
approximately 0.1 to 3.1 percent strain (compression) under a 1 kip load prior to
inundation. The samples then exhibited approximately from 3.1 (at 1 kip) to 5.1 percent
strain (compression) under a maximum 8 kip load following inundation. The samples,
however, were disturbed and based on the in-situ blow counts, the underlying paralic
deposits are suitable bearing material.
Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides
GSI conducted sampling of onsite earth materials for general soil corrosivity and soluble
sulfates, and chlorides testing. The testing (performed by an outside laboratory) included
evaluation of soil pH, soluble sulfates, chlorides, and saturated resistivity. Test results are
presented in the following table:
SATURATED SOLUBLE SAMPLE LOCATION pH RESISTIVITY SULFATES CHL AND DEPTH (FT)
SOg
156
(ohm-cm) (% by weight) 1. (
B-1 @ 2 5.14 4,200 0.0152
Corrosion Summary
Laboratory testing indicates that tested samples of the onsite soils are strongly acidic with
respect to soil acidity/alkalinity, are moderately corrosive to exposed, buried metals when
saturated, present negligible ("not applicable" per ACI 318-11) sulfate exposure to
concrete, and are somewhat elevated for chloride exposure. Reinforced concrete mix
design for foundations, slab-on-grade floors, and pavements should minimally conform to
"Exposure Class Cl" in Table 4.2.1 of ACI 318-11, as concrete would likely be exposed to
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moisture. It should be noted that GSI does not consult in the field of corrosion
engineering. The client and project architect should agree on the level of corrosion
protection required for the project and seek consultation from a qualified corrosion
consultant as warranted.
PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS
Based on our field exploration, laboratory testing, and geotechnical engineering analysis,
it is our opinion that the subject site is suitable for the proposed residential development
from a geotechnical engineering and geologic viewpoint, provided that the
recommendations presented in the following sections are incorporated into the design and
construction phases of site development. The primary geotechnical concerns with respect
to the proposed development and improvements are:
Earth materials characteristics and depth to competent bearing material.
On-going expansion and corrosion potential of site soils.
Erosiveness of site earth materials.
Potential for perched water during and following site development.
Regional seismic activity.
The recommendations presented herein considerthese as well as other aspects of the site.
The engineering analyses performed concerning site preparation and the
recommendations presented herein have been completed using the information provided
and obtained during our field work.
In the event that any significant changes are made to proposed site development, the
conclusions and recommendations contained in this report shall not be considered valid
unless the changes are reviewed and the recommendations of this report verified or
modified in writing by this office. Foundation design parameters are considered
preliminary until the foundation design, layout, and structural loads are provided to this
office for review.
Soil engineering, observation, and testing services should be provided during
grading to aid the contractor in removing unsuitable soils and in his effort to
compact the fill.
Geologic observations should be performed during any grading and foundation
construction to verify and/orfurther evaluate geologic conditions. Although unlikely,
if adverse geologic structures are encountered, supplemental recommendations
and earthwork may be warranted.
Surficial soils within approximately 3 feet from surface grades are considered
unsuitable for the support of the planned settlement-sensitive improvements (i.e.,
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residential structure, walls, concrete slab-on-grade floors, and exterior pavements,
etc.) or new planned fills. Unsuitable soils within the influence of planned
settlement-sensitive improvements and/or planned fill should be removed to expose
suitable older paralic deposits and then be reused as properly engineered fill. In
order to provide for the uniform support of the structure, a minimum 3-foot thick
layer of compacted fill is recommended for the support of structure(s), or at least
2 feet below the bottom of footings, whichever is greater. Based on the
recommended removal depths, it may be necessary to undercut the building pad
areas in order to achieve the desired minimum fill thickness. Excavations should
be completed for a minimum lateral distance of at least 5 feet beyond the building
footprint.
Testing performed on a representative sample of the onsite soils indicates very low
expansive soil conditions. On a preliminary basis, specific foundation design to
resist expansive soil effects is not necessary. However, GSI suggests that the soil
moisture within the underlying subgrade is near, or above optimum moisture
content prior to the placement of the underlayment sand and vapor retarder.
Laboratory testing indicates that site soils are strongly acidic (pH), and moderately
corrosive to exposed buried metals when saturated. Testing also indicates that site
soils present negligible ("not applicable" per ACI 318-11) sulfate exposure to
concrete, and somewhat elevated for chloride exposure. Site soils are classified as
"Exposure Class Cl." The client and project architect should agree on the level of
corrosion protection required for the project and seek consultation from a qualified
corrosion consultant, as warranted. Additional testing at the completion of remedial
grading is recommended in order to verify these assumptions.
Site soils are considered erosive. Surface drainage should be designed to eliminate
the potential for concentrated flows. Positive surface drainage away from
foundations and tops of slopes is recommended. Temporary erosion control
measures should be implemented until vegetative covering is well established. The
homeowner will need to maintain proper surface drainage over the life of the
project.
A high regional groundwater table was not encountered; however, a perched
groundwater was observed during our subsurface exploration within the property.
Due to the nature of site earth materials, there is a potential for the perched water
to become further influenced both during and following site development. The
perched groundwater condition should be disclosed to all interested/affected
parties. Should perched water conditions be encountered, this office could provide
recommendations for mitigation. Typical mitigation includes subdrainage system,
cut-off barriers, etc.
On a preliminary basis, temporary slopes should be constructed in accordance with
CAL-OSHA guidelines for Type "B" soils. All temporary slopes should be evaluated
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by the geotechnical consultant, prior to worker entry. Should adverse conditions
be identified, the slope may need to be laid back to a flatter gradient or require the
use of shoring.
The seismicity-acceleration values provided herein should be considered during the
design and construction of the proposed development.
General Earthwork and Grading Guidelines are provided at the end of this report as
Appendix E. Specific recommendations are provided below.
EARTHWORK CONSTRUCTION RECOMMENDATIONS
General
All earthwork should conform to the guidelines presented in the 2013 CBC (CBSC, 2013),
the requirements of the City of Carlsbad, and the General Earthwork and Grading
Guidelines presented in Appendix E, except where specifically superceded in the text of
this report. Prior to earthwork, a GSI representative should be present at the
preconstruction meeting to provide additional earthwork guidelines, if needed, and review
the earthwork schedule. This office should be notified in advance of any fill placement,
supplemental regrading of the site, or backfilling underground utility trenches and retaining
walls after rough earthwork has been completed. This includes grading for driveway
approaches, driveways, and exterior hardscape.
During earthwork construction, all site preparation and the general grading procedures of
the contractor should be observed and the fill selectively tested by a representative (s) of
GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed
by this office and, if warranted, modified and/or additional recommendations will be
offered. All applicable requirements of local and national construction and general industry
safety orders, the Occupational Safety and Health Act (OSHA), and the Construction Safety
Act should be met. It is the onsite general contractor and individual subcontractors
responsibility to provide a save working environment for our field staff who are onsite. GSI
does not consult in the area of safety engineering.
Demolition/Grubbing
Vegetation and any miscellaneous debris should be removed from the areas of
proposed grading.
Any existing subsurface structures uncovered during the recommended removal
should be observed by GSI so that appropriate remedial recommendations can be
provided.
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3. Cavities or loose soils remaining after demolition and site clearance should be
cleaned out and observed by the soil engineer. The cavities should be replaced
with fill materials that have been moisture conditioned to at least optimum moisture
content and compacted to at least 90 percent of the laboratory standard.
1 4. Onsite septic systems (if encountered) should be removed in accordance with
San Diego County Department of Environmental Health standards/guidelines.
Treatment of Existing Ground
Removals should consist of all surficial deposits of fill, colluvium, and weathered
paralic deposits. Based on our site work, removals depths on the order of 3 feet
should be anticipated. These soils may be re-used as fill, provided that the soil is
cleaned of any deleterious material and moisture conditioned, and compacted to
a minimum 90 percent relative compaction per ASTM D 1557. Removals should be
completed throughout the entire building area.
In addition to removals within the building envelopes, overexcavation/undercutting
of the underlying formational soil should be performed in order to provide for at
least 3 feet of compacted fill below finish grade or 2 feet below the bottom of
footings, whichever is greater. Undercutting should be completed for a minimum
lateral distance of at least 5 feet beyond the building footprint. Once removals and
overexcavation is completed, the fill should be cleaned of deleterious materials,
moisture conditioned, and recompacted to at least 90 percent relative compaction
per ASTM D 1557.
Subsequent to the above removal s/ove rexcavation, the exposed bottom should be
scarified to a depth of at least 6 to 8 inches, brought to at least optimum moisture
content, and recompacted to a minimum relative compaction of 90 percent of the
laboratory standard, prior to any fill placement.
Existing fill and removed natural ground materials may be reused as compacted fill
provided that major concentrations of vegetation and miscellaneous debris are
removed from the site, prior to or during fill placement.
Localized deeper removals may be necessary due to buried drainage channel
meanders or dry porous materials, septic systems, etc. The project soils
engineer/geologist should observe all removal areas during the grading.
Fill Suitability
Existing earth materials onsite should generate relatively fine grained, granular fill material,
and oversize material (i.e., greater than 12 inches in long dimension) is not anticipated. If
soil importation is planned, samples of the soil import should be evaluated by this office
prior to importing in order to assure compatibility with the onsite site soils and the
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recommendations presented in this report. Import soils, if used, should be relatively sandy
and very low expansive (i.e., E.I. less than 20).
Fill Placement
Subsequent to ground preparation, fill materials should be brought to at least
optimum moisture content, placed in thin 6- to 8-inch lifts, and mechanically
compacted to obtain a minimum relative compaction of 90 percent of the laboratory
standard.
Fill materials should be cleansed of major vegetation and debris prior to placement.
Any import materials should be observed and deemed suitable by the soils
engineer prior to placement on the site. Foundation designs may be altered if
import materials have a greater expansion value than the onsite materials
encountered in this investigation.
Graded Slopes
Significant graded slope are not planned, nor anticipated for this project.
Temporary Slopes
Temporary slopes (not anticipated for this study) for excavations greater than 4 feet, but
less than 20 feet in overall height should conform to CAL-OSHA and/or OSHA
requirements for Type "B" soils. Temporary slopes, up to a maximum height of ±20 feet,
may be excavated at a 1:1 (h:v) gradient, or flatter, provided groundwater and/or running
sands are not exposed. Construction materials or soil stockpiles should not be placed
within 'H' of any temporary slope where 'H' equals the height of the temporary slope. All
temporary slopes should be observed by a licensed engineering geologist and/or
geotechnical engineer prior to worker entry into the excavation.
PRELIMINARY RECOMMENDATIONS - FOUNDATIONS
General
Preliminary recommendations for foundation design and construction are provided in the
following sections. These preliminary recommendations have been developed from our
understanding of the currently planned site development, site observations, subsurface
exploration, laboratory testing, and engineering analyses. Foundation design should be
re-evaluated at the conclusion of site grading/remedial earthwork for the as-graded soil
conditions. Although not anticipated, revisions to these recommendations may be
necessary. In the event that the information concerning the proposed development plan
is not correct, or any changes in the design, location or loading conditions of the proposed
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additions are made, the conclusions and recommendations contained in this report shall
not be considered valid unless the changes are reviewed and conclusions of this report
are modified or approved in writing by this office.
The information and recommendations presented in this section are not meant to
supercede design by the project structural engineer or civil engineer specializing in
structural design. Upon request, GSI could provide additional input/consultation regarding
soil parameters, as related to foundation design.
Preliminary Foundation Design
The foundation systems should be designed and constructed in accordance with
guidelines presented in the 2013 CBC (CBSC, 2013).
An allowable bearing value of 2,000 pounds per square foot (psf) may be used for
the design of footings that maintain a minimum width of 18 inches and a minimum
depth of 12 inches (below the lowest adjacent grade) and are founded entirely into
properly compacted, engineered fill. This value may be increased by 20 percent for
each additional 12 inches in footing depth to a maximum value of 2,500 psf. These•
values may be increased by one-third when considering short duration seismic or
wind loads. Isolated pad footings should have a minimum dimension of at least
24 inches square and a minimum embedment of 24 inches below the lowest
adjacent grade into properly engineered fill. Foundation embedment depth
excludes concrete slabs-on-grade, and/or slab underlayment. Foundations should
not simultaneously bear on unweathered paralic deposits and engineered fill.
For foundations deriving passive resistance from engineered fill, a passive earth
pressure may be computed as an equivalent fluid having a density of 250 pcf, with
a maximum earth pressure of 2,500 psf.
The upper 6 inches of passive pressure should be neglected if not confined by
slabs or pavement.
For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a
concrete to soil contact when multiplied by the dead load.
When combining passive pressure and frictional resistance, the passive pressure
component should be reduced by one-third.
All footing setbacks from slopes should comply with Figure 1808.7.1 of the
2013 CBC (CBSC, 2013). GSI recommends a minimum horizontal setback distance
of 7 feet as measured from the bottom, outboard edge of the footing to the slope
face.
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8. Footings for structures adjacent to retaining walls should be deepened so as to
extend below a 1:1 projection from the heel of the wall. Alternatively, walls may be
designed to accommodate structural loads from buildings or appurtenances as
described in the "Retaining Wall" section of this report.
PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS
The following foundation construction recommendations are presented as a minimum
criteria from a soils engineering viewpoint. The following foundation construction
recommendations are intended to support planned improvements underlain by at least
7 feet of non-detrimentally expansive soils (i.e., E.I.<21 and P1 <15). Although not
anticipated based on the available data, should foundations be underlain by expansive
soils they will require specific design to mitigate expansive soil effects as required in
Sections 1808.6.1 or 1808.6.2 of the 2013 CBC (CBSC, 2013).
Exterior and interior footings should be founded into engineered fill at a minimum
depth of 18 or 24 inches below the lowest adjacent grade, and a minimum width of
15 or 18 inches, for the planned, two and three story floor load structure,
respectively. Isolated, exterior column and panel pads, or wall footings, should be
at least 24 inches, square, and founded at a minimum depth of 24 inches into
properly engineered fill. All footings should be minimally reinforced with two No. 4
reinforcing bars, one placed near the top and one placed near the bottom of the
footing. Depth of embedment does not include slab underlayment, landscape
zone, etc.
All interior and exterior column footings, and perimeter wall footings, should be tied
together via grade beams in at least one direction. The grade beam should be at
least 12 inches square into the main foundation in cross section, and should be
provided with a minimum of one No.4 reinforcing bar at the top, and one No.4
reinforcing bar at the bottom of the grade beam. The base of the reinforced grade
beam should be at the same elevation as the adjoining footings.
A grade beam, reinforced as previously recommended and at least 12 inches
square, should be provided across large (garage) entrances. The base of the
reinforced grade beam should be at the same elevation as the adjoining footings.
A minimum concrete slab-on-grade thickness of 5 inches is recommended.
Recommendations for floor slab underlayment are presented in a later section of
this report.
Concrete slabs should be reinforced with a minimum of No. 3 reinforcement bars
placed at 18-inch on centers, in two horizontally perpendicular directions (i.e., long
axis and short axis), ans as determined by the structural engineer/slab designer,
based on actual loads.
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All slab reinforcement should be supported to ensure proper mid-slab height
positioning during placement of the concrete. "Hooking" of reinforcement is not an
acceptable method of positioning.
The project structural engineer should consider the use of transverse and
longitudinal control joints to help control slab cracking due to concrete shrinkage
or expansion. Two of the best ways to control this movement are: 1) add a sufficient
amount of reinforcing steel to increase the tensile strength of the slab; and 2)
provide an adequate amount of control and/or expansion joints to accommodate
anticipated concrete shrinkage and expansion. Transverse and longitudinal crack
control joints should be spaced no more than 12 feet on center and constructed to
a minimum depth of T/4, where 'T' equals the slab thickness in inches.
Prior to the placement of underlayment sand and vapor retarder, GSI recommends
that the slab subgrade materials be moisture conditioned to at least optimum
moisture content to a minimum depth of 12 inches. Slab subgrade moisture
content should be evaluated by the geotechnical consultant within 72 hours of the
placement of the underlayment sand and vapor retarder.
Soils generated from footing excavations to be used onsite should be compacted
to a minimum relative compaction of 90 percent of the laboratory standard
(ASTM D 1557), whether the soils are to be placed inside the foundation perimeter
or in the side yard/right-of-way areas. This material must not alter positive drainage
patterns that direct drainage away from the structural areas and toward the street.
Reinforced concrete mix design should conform to "Exposure Class Cl" in
Table 4.2.1 of ACI-318-11 since concrete would likely be exposed to moisture.
Foundation Settlement
Provided that the earthwork and foundation recommendations in this reported are adhered
to, foundations bearing on engineered fill should be minimally designed to accommodate
a differential settlement of 1-inch over a 40-foot horizontal span (angular distortion =
1/480), or between dissimilarly loaded foundation elements. These preliminary settlement
values do not apply to improvements constructed within 2013 CBC setbacks or within the
influence of unmitigated soils. In addition, these values do not take seismic effects from
strong ground motion into account.
SOIL MOISTURE TRANSMISSION CONSIDERATIONS
GSI has evaluated the potential for vapor or water transmission through the concrete floor
slab, in light of typical floor coverings and improvements. Please note that slab moisture
emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from atypical slab
(Kanare, 2005), while floor covering manufacturers generally recommend about
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3 Ibs/24 hours as an upper limit. The recommendations in this section are not intended
to preclude the transmission of water or vapor through the foundation or slabs.
Foundation systems and slabs shall not allow water or water vapor to enter into the
structure so as to cause damage to another building component or to limit the installation
of the type of flooring materials typically used for the particular application (State of
California, 2016). These recommendations may be exceeded or supplemented by a water
"proofing" specialist, project architect, or structural consultant. Thus, the client will need
to evaluate the following in light of a cost vs. benefit analysis (owner expectations and
repairs/replacement), along with disclosure to all interested/affected parties. It should also
be noted that vapor transmission will occur in new slab-on-grade floors as a result of
chemical reactions taking place within the curing concrete. Vapor transmission through
concrete floor slabs as a result of concrete curing has the potential to adversely affect
sensitive floor coverings depending on the thickness of the concrete floor slab and the
duration of time between the placement of concrete, and the floor covering. It is possible
that a slab moisture sealant may be needed prior to the placement of sensitive floor
coverings if a thick slab-on-grade floor is used and the time frame between concrete and
floor covering placement is relatively short.
Considering the E. I. test results presented herein, and known soil conditions in the region,
the anticipated typical water vapor transmission rates, floor coverings, and improvements
(to be chosen by the Client and/or project architect) that can tolerate vapor transmission
rates without significant distress, the following alternatives are provided:
Concrete slabs should be thicker.
Concrete slab underlayment should consist of a 15-mil vapor retarder, or equivalent,
with all laps sealed per the 2013 CBC and the manufacturer's recommendation.
The vapor retarder should comply with the ASTM E 1745- Class A criteria, and be
installed in accordance with ACI 302.1 R-04 and ASTM E 1643.
The 15-mil vapor retarder (ASTM E 1745 - Class A) shall be installed per the
recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting,
rebar, etc.).
Concrete slabs, shall be underlain by 2 inches of clean, washed sand (SE > 30)
above a 15-mil vapor retarder (ASTM E-1 745 - Class A, per Engineering Bulletin 119
[Kanare, 2005]) installed per the recommendations of the manufacturer, including
all penetrations (i.e., pipe, ducting, rebar, etc.). The manufacturer shall provide
instructions for lap sealing, including minimum width of lap, method of sealing, and
either supply or specify suitable products for lap sealing (ASTM E 1745), and per
code.
ACI 302.1 R-04 (2004) states "If a cushion or sand layer is desired between the
vapor retarder and the slab, care must be taken to protect the sand layer from
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taking on additional water from a source such as rain, curing, cutting, or cleaning.
Wet cushion or sand layer has been directly linked in the past to significant
lengthening of time required for a slab to reach an acceptable level of dryness for
floor covering applications." Therefore, additional observation and/ortesting will be
necessary for the cushion or sand layer for moisture content, and relatively uniform
thicknesses, prior to the placement of concrete.
The vapor retarder shall be underlain by 2 inches of sand (SE > 30) placed directly
on the prepared, moisture conditioned, subgrade and should be sealed to provide
a continuous retarder under the entire slab, as discussed above. As discussed
previously, GSI indicated this layer of import sand may be eliminated below the
vapor retarder, if laboratory testing indicates that the slab subgrade soils have a
sand equivalent (SE) of 30 oy greater, during site grading.
Concrete should have a maximum water/cement ratio of 0.50. This does not
supercede Table 4.2.1 of Chapter 4 of the ACI (2011) for corrosion or other
corrosive requirements. Additional concrete mix design recommendations should
be provided by the structural consultant and/or waterproofing specialist. Concrete
finishing and workablity should be addressed by the structural consultant and a
waterproofing specialist.
Where slab water/cement ratios are as indicated herein, and/or admixtures used,
the structural consultant should also make changes to the concrete in the grade
beams and footings in kind, so that the concrete used in the foundation and slabs
are designed and/or treated for more uniform moisture protection.
The owner(s) should be specifically advised which areas are suitable for tile flooring,
vinyl flooring, or other types of water/vapor-sensitive flooring and which are not
suitable. In all planned floor areas, flooring shall be installed per the manufactures
recommendations.
Additional recommendations regarding water or vapor transmission should be
provided by the architect/structural engineer/slab or foundation designer and
should be consistent with the specified floor coverings indicated by the architect.
Regardless of the mitigation, some limited moisture/moisture vapor transmission through
the slab should be anticipated. Construction crews may require special training for
installation of certain product(s), as well as concrete finishing techniques. The use of
specialized product(s) should be approved by the slab designer and water-proofing
consultant. A technical representative of the flooring contractor should review the slab and
moisture retarder plans and provide comment prior to the construction of the foundations
or improvements. The vapor retarder contractor should have representatives onsite during
the initial installation.
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DRIVEWAY/PARKING, FLATWORK, AND OTHER IMPROVEMENTS
The effects of expansive soils are cumulative, and typically occur over the lifetime of any
improvements. On relatively level areas, when the soils are allowed to dry, the dessication
and swelling process tends to cause heaving and distress to flatwork and other
improvements. The resulting potential for distress to improvements may be reduced, but
not totally eliminated. To that end, it is important that the homeowner be aware of this
long-term potential for distress. To reduce the likelihood of distress, the following
recommendations are presented for all exterior flatwork:
The subgrade area for concrete slabs should be compacted to achieve a minimum
90 percent relative compaction (sidewalks, patios), and 95 percent relative
compaction (traffic pavements), and then be presoaked to 2 to 3 percentage points
above (or 125 percent of) the soils' optimum moisture content, to a depth of
18 inches below subgrade elevation. If very low expansive soils are present, only
optimum moisture content, or greater, is required and specific presoaking is not
warranted. The moisture content of the subgrade should be proof tested within
72 hours prior to pouring concrete.
Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch
layer of crushed rock, gravel, or clean sand, that should be compacted and level
prior to pouring concrete. If very low expansive soils are present, the rock or gravel
or sand may be deleted. The layer pr subgrade should be wet-down completely
prior to pouring concrete, to minimize loss of concrete moisture to the surrounding
earth materials.
Exterior, non-vehicle slabs (sidewalks, patios, etc.) should be a minimum of
4 inches thick.
Driveway and parking area concrete slabs and approaches should be at least
51/2 inches thick. A thickened edge (12 inches) should also be considered adjacent
to all landscape areas, to help impede infiltration of landscape water under the
slab(s). All pavement construction should minimally be performed in general
accordance with industry standards and properly transitioned.
Asphaltic pavements should minimally consist of 4 inches asphalt over 4 inches of
compacted aggregate base per the City.
Trash truck loading areas should be designed per Carlsbad City standard drawings.
The use of transverse and longitudinal control joints are recommended to help
control slab cracking due to concrete shrinkage or expansion. Two ways to
mitigate such cracking are: a) add a sufficient amount of reinforcing steel,
increasing tensile strength of the slab; and, b) provide an adequate amount of
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control and/or expansion joints to accommodate anticipated concrete shrinkage
and expansion.
In order to reduce the potential for unsightly cracks, slabs should be reinforced at
mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each
direction. If subgrade soils within the top 7 feet from finish grade are very low
expansive soils (i.e., E.I. ~20), then 6x6-W1.4xW1.4 welded-wire mesh may be
substituted for the rebar, provided the reinforcement is placed on chairs, at slab
mid-height. The exterior slabs should be scored or saw cut, ½ to % inches deep,
often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or
narrow slabs, control joints should be provided at intervals of every 6 feet. The
slabs should be separated from the foundations and sidewalks with expansion joint
filler material.
No traffic should be allowed upon the newly poured concrete slabs until they have
been properly cured to within 75 percent of design strength. Concrete compression
strength should be a minimum of 2,500 psi for sidewalks and patios, and a
minimum 3,250 psi for traffic pavements.
Driveways, sidewalks, and patio slabs adjacent to the structure should be separated
from the structure with thick expansion joint filler material. In areas directly adjacent
to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should
be additionally sealed with flexible mastic.
Planters and walls should not be tied to the structure.
Overhang structures should be supported on the slabs, or structurally designed
with continuous footings tied in at least two directions. If very low expansion soils
are present, footings need only be tied in one direction.
Any masonry landscape walls that are to be constructed throughout the property
should be grouted and articulated in segments no more than 20 feet long. These
segments should be keyed or doweled together.
Utilities should be enclosed within a closed utilidor (vault) or designed with flexible
connections to accommodate differential settlement and expansive soil conditions.
Positive site drainage should be maintained at all times. Finish grade on the lot
should provide a minimum of 1 to 2 percent fall to the Street, as indicated herein.
It should be kept in mind that drainage reversals could occur, including
post-construction settlement, if relatively flat yard drainage gradients are not
periodically maintained by the homeowner.
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Air conditioning (NC) units should be supported by slabs that are incorporated into
the building foundation or constructed on a rigid slab with flexible couplings for
plumbing and electrical lines. NC waste water lines should be drained to a suitable
non-erosive outlet.
Shrinkage cracks could become excessive if proper finishing and curing practices
are not followed. Finishing and curing practices should be performed per the
Portland Cement Association Guidelines. Mix design should incorporate rate of
curing for climate and time of year, sulfate content of soils, corrosion potential of
soils, and fertilizers used on site.
DEVELOPMENT CRITERIA
Onsite Storm Water Treatment
Based on our evaluation, onsite storm water treatment systems should consider the
following:
Site soils (i.e., proposed compacted fill) are considered to belong to hydrologic
subgroup "B"; however, proposed compacted fill is considered to belong to
hydraulic subgroup "D."
The presence of the thin surficial fill layer overlying dense formational soil will
increase the potential for the development of a perched water table along the
fill/formation contact.
There will be an increased potential for the adverse performance of structures,
should the engineered fills supporting the proposed structures become saturated,
due to settlement, or water vapor transmission, both onsite and offsite. This may
also affect utility trench backfill causing settlement and/or piping, both onsite and
offsite.
Impermeable liners and subdrains should be used along the bottom of bioretention
swales/basins located within the influence of improvements on slopes.
Impermeable liners used in conjunction with bioretention basins should consist of
a 30-mil polyvinyl chloride (PVC) membrane that is covered by a minimum of
12 inches of clean soil, free from rocks and debris, with a maximum 4:1 (h:v) slope
inclination, or flatter, and meets the following minimum specifications:
Specific Gravity (ASTM D792): 1.2 (g/cc, mm.); Tensile (ASTM D882):
73 (lb/in-width, mm); Elongation at Break (ASTM D882): 380 (%, mm);
Modulus (ASTM D882): 30 (lb/in-width, mm.); and Tear Strength
(ASTM D1004):8 (lb/in, mm); Seam Shear Strength (ASTM D882) 58.4 (lb/in,
mm); Seam Peel Strength (ASTM D882) 15 (lb/in, mm).
Richard Smerud W.O. 7099-A-SC
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Subdrains should consist of at least 4-inch diameter Schedule 40 or SDR 35 drain
pipe with perforations oriented down. The drain pipe should be sleeved with a filter
sock, then tight-lines, and directed to a suitable outlet.
In practice, storm water BMP's are usually initially designed by the project design civil
engineer. Selection of methods should include (but should not be limited to) review by
licensed professionals including the geotechnical engineer, hydrogeologist, engineering
geologist, project civil engineer, landscape architect, environmental professional, and
industrial hygienist. Applicable governing agency requirements should be reviewed and
included in design considerations.
Slope Maintenance and Planting
Water has been shown to weaken the inherent strength of all earth materials. Slope
stability is significantly reduced by overly wet conditions. Positive surface drainage away
from slopes should be maintained and only the amount of irrigation necessary to sustain
plant life should be provided for planted slopes. Over-watering should be avoided as it
adversely affects site improvements, and causes perched groundwater conditions. Graded
slopes constructed utilizing onsite materials would be erosive. Eroded debris may be
minimized and surficial slope stability enhanced by establishing and maintaining a suitable
vegetation cover soon after construction. Compaction to the face of fill slopes would tend
to minimize short-term erosion until vegetation is established. Plants selected for
landscaping should be light weight, deep rooted types that require little water and are
capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may
aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those
recommended above will increase the potential for perched water, staining, mold, etc., to
develop. A rodent control program to prevent burrowing should be implemented.
Irrigation of natural (ungraded) slope areas is generally not recommended. These
recommendations regarding plant type, irrigation practices, and rodent control should be
provided to all interested/affected parties. Over-steepening of slopes should be avoided
during building construction activities and landscaping.
Drainage
Adequate surface drainage is a very important factor in reducing the likelihood of adverse
performance of foundations, hardscape, and slopes. Surface drainage should be sufficient
to mitigate ponding of water anywhere on the property, and especially near structures and
tops of slopes. Surface drainage should be carefully taken into consideration during fine
grading, landscaping, and building construction. Therefore, care should be taken that
future landscaping or construction activities do not create adverse drainage conditions.
Positive site drainage within the property should be provided and maintained at all times.
Drainage should not flow uncontrolled down any descending slope. Water should be
directed away from foundations and tops of slopes, and not allowed to pond and/or seep
into the ground. In general, site drainage should conform to Section 1804.3 of the
2013 CBC. Consideration should be given to avoiding construction of planters adjacent
Richard Smerud W.O. 7099-A-SC
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to structures (buildings, pools, spas, etc.). Building pad drainage should be directed
toward the street or other approved area(s). Although not a geotechnical requirement, roof
gutters, down spouts, or other appropriate means may be utilized to control roof drainage.
Down spouts, or drainage devices should outlet a minimum of 5 feet from structures or into
a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy
rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas
of seepage develop, recommendations for minimizing this effect could be provided upon
request.
Erosion Control
Cut and fill slopes will be subject to surficial erosion during and after grading. Onsite earth
materials have a moderate to high erosion potential. Consideration should be given to
providing hay bales and silt fences for the temporary control of surface water, from a
geotechnical viewpoint.
Landscape Maintenance
Only the amount of irrigation necessary to sustain plant life should be provided.
Over-watering the landscape areas will adversely affect proposed site improvements. We
would recommend that any proposed open-bottom planters adjacent to proposed
structures be eliminated for a minimum distance of 10 feet. As an alternative,
closed-bottom type planters could be utilized. An outlet placed in the bottom of the
planter, could be installed to direct drainage away from structures or any exterior concrete
flatwork. If planters are constructed adjacent to structures, the sides and bottom of the
planter should be provided with a moisture retarder to prevent penetration of irrigation
water into the subgrade. Provisions should be made to drain the excess irrigation water
from the planters without saturating the subgrade below or adjacent to the planters.
Graded slope areas should be planted with drought resistant vegetation. Consideration
should be given to the type of vegetation chosen and their potential effect upon surface
improvements (i.e., some trees will have an effect on concrete flatwork with their extensive
root systems). From a geotechnical standpoint leaching is not recommended for
establishing landscaping. If the surface soils are processed for the purpose of adding
amendments, they should be recompacted to 90 percent minimum relative compaction.
Gutters and Downspouts
As previously discussed in the drainage section, the installation of gutters and downspouts
should be considered to collect roof water that may otherwise infiltrate the soils adjacent
to the structures. If utilized, the downspouts should be drained into PVC collector pipes
or other non-erosive devices (e.g., paved swales or ditches; below grade, solid tight-lined
PVC pipes; etc.), that will carry the water away from the structure, to an appropriate outlet,
in accordance with the recommendations of the design civil engineer. Downspouts and
gutters are not a requirement; however, from a geotechnical viewpoint, provided that
positive drainage is incorporated into project design (as discussed previously).
Richard Smerud W.O. 7099-A-SC
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Subsurface and Surface Water
Subsurface and surface water are not anticipated to affect site development, provided that
the recommendations contained in this report are incorporated into final design and
construction and that prudent surface and subsurface drainage practices are incorporated
into the construction plans. Perched groundwater conditions along zones of contrasting
permeabilities may not be precluded from occurring in the future due to site irrigation, poor
drainage conditions, or damaged utilities, and should be anticipated. Should perched
groundwater conditions develop, this office could assess the affected area(s) and provide
the appropriate recommendations to mitigate the observed groundwater conditions.
Groundwater conditions may change with the introduction of irrigation, rainfall, or other
factors.
Site Improvements
If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the
site, recommendations concerning the geological or geotechnical aspects of design and
construction of said improvements could be provided upon request. Pools and/or spas
should not be constructed without specific design and construction recommendations from
GSI, and this construction recommendation should be provided to all interested/affected
parties. This office should be notified in advance of any fill placement, grading of the site,
or trench backfilling after rough grading has been completed. This includes any grading,
utility trench and retaining wall backfills, flatwork, etc.
Tile Flooring
Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small
cracks in a conventional slab may not be significant. Therefore, the designer should
consider additional steel reinforcement for concrete slabs-on-grade where tile will be
placed. The tile installer should consider installation methods that reduce possible
cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane
(approved by the Tile Council of America/Ceramic Tile Institute) are recommended
between tile and concrete slabs on grade.
Additional Grading
This office should be notified in advance of any fill placement, supplemental regrading of
the site, or trench backfilling after rough grading has been completed. This includes
completion of grading in the street, driveway approaches, driveways, parking areas, and
utility trench and retaining wall backfills.
Footing Trench Excavation
All footing excavations should be observed by a representative of this firm subsequent to
trenching and prior to concrete form and reinforcement placement. The purpose of the
Richard Smerud W.O. 7099-A-SC
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observations is to evaluate that the excavations have been made into the recommended
bearing material and to the minimum widths and depths recommended for construction.
If loose or compressible materials are exposed within the footing excavation, a deeper
footing or removal and recompaction of the subgrade materials would be recommended
at that time. Footing trench spoil and any excess soils generated from utility trench
excavations should be compacted to a minimum relative compaction of 90 percent, if not
removed from the site.
Trenching/Temporary Construction Backcuts
Considering the nature of the onsite earth materials, it should be anticipated that caving
or sloughing could be a factor in subsurface excavations and trenching. Shoring or
excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees
[except as specifically superceded within the text of this report]), should be anticipated.
All excavations should be observed by an engineering geologist or soil engineer from GSI,
prior to workers entering the excavation or trench, and minimally conform to CAL-OSHA,
state, and local safety codes. Should adverse conditions exist, appropriate
recommendations would be offered at that time. The above recommendations should be
provided to any contractors and/or subcontractors, or homeowners, etc., that may perform
such work.
Utility Trench Backfill
All interior utility trench backfill should be brought to at least 2 percent above
optimum moisture content and then compacted to obtain a minimum relative
compaction of 90 percent of the laboratory standard. As an alternative for shallow
(12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of
30 or greater may be utilized and jetted or flooded into place. Observation, probing
and testing should be provided to evaluate the desired results.
Exterior trenches adjacent to, and within areas extending below a 1:1 plane
projected from the outside bottom edge of the footing, and all trenches beneath
hardscape features and in slopes, should be compacted to at least 90 percent of
the laboratory standard. Sand backfill, unless excavated from the trench, should
not be used in these backfill areas. Compaction testing and observations, along
with probing, should be accomplished to evaluate the desired results.
All trench excavations should conform to CAL-OSHA, state, and local safety codes.
Utilities crossing grade beams, perimeter beams, or footings should either pass
below the footing or grade beam utilizing a hardened collar or foam spacer, or pass
through the footing or grade beam in accordance with the recommendations of the
structural engineer.
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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SUMMARY OF RECOMMENDATIONS REGARDING
GEOTECHNICAL OBSERVATION AND TESTING
We recommend that observation and/or testing be performed by GSI at each of the
following construction stages:
During grading/recertification.
During excavation.
During placement of subdrains or other subdrainage devices, prior to placing fill
and/or backfill.
After excavation of building footings, retaining wall footings, and free standing walls
footings, prior to the placement of reinforcing steel or concrete.
Prior to pouring any slabs or flatwork, after p resoaki ng/presatu ration of building
pads and other flatwork subgrade, before the placement of concrete, reinforcing
steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders (i.e., visqueen,
etc.).
During placement of backfill for area drain, interior plumbing, utility line trenches,
and retaining wall backfill.
During slope construction/repair.
When any unusual soil conditions are encountered during any construction
operations, subsequent to the issuance of this report.
When any homeowner improvements, such as flatwork, spas, pools, walls, etc., are
constructed, prior to construction.
A report of geotechnical observation and testing should be provided at the
conclusion of each of the above stages, in order to provide concise and clear
documentation of site work, and/or to comply with code requirements.
OTHER DESIGN PROFESSIONALS/CONSULTANTS
The design civil engineer, structural engineer, post-tension designer, architect, landscape
architect, wall designer, etc., should review the recommendations provided herein,
incorporate those recommendations into all their respective plans, and by explicit
reference, make this report part of their project plans. This report presents minimum
design criteria for the design of slabs, foundations and other elements possibly applicable
to the project. These criteria should not be considered as substitutes for actual designs
Richard Smerud W.O. 7099-A-SC
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by the structural engineer/designer. Please note that the recommendations contained
herein are not intended to preclude the transmission of water or vapor through the slab or
foundation. The structural engineer/foundation and/or slab designer should provide
recommendations to not allow water or vapor to enter into the structure so as to cause
damage to another building component, or so as to limit the installation of the type of
flooring materials typically used for the particular application.
The structural engineer/designer should analyze actual soil-structure interaction and
consider, as needed, bearing, expansive soil influence, and strength, stiffness and
deflections in the various slab, foundation, and other elements in order to develop
appropriate, design-specific details. As conditions dictate, it is possible that other
influences will also have to be considered. The structural engineer/designer should
consider all applicable codes and authoritative sources where needed. If analyses by the
structural engineer/designer result in less critical details than are provided herein as
minimums, the minimums presented herein should be adopted. It is considered likely that
some, more restrictive details will be required.
If the structural engineer/designer has any questions or requires further assistance, they
should not hesitate to call or otherwise transmit their requests to GSI. In order to mitigate
potential distress, the foundation and/or improvement's designer should confirm to GSI
and the governing agency, in writing, that the proposed foundations and/or improvements
can tolerate the amount of differential settlement and/or expansion characteristics and
other design criteria specified herein.
PLAN REVIEW
Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.),
should be reviewed by this office prior to construction, so that construction is in
accordance with the conclusions and recommendations of this report. Based on our
review, supplemental recommendations and/or further geotechnical studies may be
warranted.
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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LIMITATIONS
The materials encountered on the project site and utilized for our analysis are believed
representative of the area; however, soil and bedrock materials vary in character between
excavations and natural outcrops or conditions exposed during mass grading. Site
conditions may vary due to seasonal changes or other factors.
Inasmuch as our study is based upon our review and engineering analyses and laboratory
data, the conclusions and recommendations are professional opinions. These opinions
have been derived in accordance with current standards of practice, and no warranty,
either express or implied, is given. Standards of practice are subject to change with time.
GSI assumes no responsibility or liability for work or testing performed by others, or their
inaction; or work performed when GSI is not requested to be onsite, to evaluate if our
recommendations have been properly implemented. Use of this report constitutes an
agreement and consent by the user to all the limitations outlined above, notwithstanding
any other agreements that may be in place. In addition, this report may be subject to
review by the controlling authorities. Thus, this report brings to completion our scope of
services for this portion of the project. All samples will be disposed of after 30 days, unless
specifically requested by the client, in writing.
Richard Smerud W.O. 7099-A-SC
906 Pine Avenue, Carlsbad August 12, 2016
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APPENDIX A
REFERENCES
GeoSoils, Inc.
APPENDIX A
REFERENCES
American Concrete Institute, 2011, Building code requirements for structural concrete
(ACI 318-11), an ACI standard and commentary: reported by ACI Committee 318;
dated May 24.
ACI Committee 302, 2004, Guide for concrete floor and slab construction, ACI 302.1 R-04,
dated June.
American Society for Testing and Materials (ASTM),1998, Standard practice for installation
of water vapor retarder used in contact with earth or granular fill under concrete
slabs, Designation: E 1643-98 (Reapproved 2005).
1997, Standard specification for plastic water vapor retarders used in contact with
soil or granular fill under concrete slabs, Designation: E 1745-97 (Reapproved
2004).
American Society of Civil Engineers, 2010, Minimum design loads for buildings and other
structures, ASCE Standard ASCE/SEI 7-10.
Blake, Thomas F., 2000a, EQFAULT, A computer program for the estimation of peak
horizontal acceleration from 3-D fault sources; Windows 95/98 version.
2000b, EQSEARCH, A computer program for the estimation of peak horizontal
acceleration from California historical earthquake catalogs; Updated to December
2009, Windows 95/98 version.
Bozorgnia, V., Campbell K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics,
relationship with horizontal component, and building-code implications;
Proceedings of the SMlP99 seminar on utilization of strong-motion data,
September 15, Oakland, pp. 23-49.
Bryant, W.A., and Hart, E.W., 2007, Fault-rupture hazard zones in California, Alquist-Priolo
earthquake fault zoning act with index to earthquake fault zones maps;
California Geological Survey, Special Publication 42, interim revision.
California Building Standards Commission, 2013, California Building Code, California Code
of Regulations, Title 24, Part 2, Volume 2 of 2*, Based on the 2012 International
Building Code, 2013 California Historical Building Code, Title 24, Part 8; 2013
California Existing Building Code, Title 24, Part 10.
Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., 2003, The revised 2002
California probabilistic seismic hazard maps, dated June,
http ://www. conservation .ca. gov/cgs/rgh m/psha/fau lt_parameters/pdf/Documents
/2002_CA_Hazard_Maps. pdf
GeoSoils, Inc.
Carlsbad, City of, 1993, Standards for design and construction of public works
improvements in the City of Carlsbad.
Jennings, C.W., and Bryant, W.A., 2010, Fault activity map of California, scale 1:750,000,
California Geological Survey, Geologic Data Map No. 6.
Kanare, H.M., 2005, Concrete floors and moisture, Engineering Bulletin 119, Portland
Cement Association.
Kennedy, M.P., and Tan, SS., 2007, Geologic map of the Oceanside 30' by 60' quadrangle,
California, regional geologic map series scale 1:100,000, California Geologic
Survey Map No. 2.
Romanoff, M., 1957, Underground corrosion, originally issued April 1.
Seed, 2005, Evaluation and mitigation of soil liquefaction hazard "evaluation of field data
and procedures for evaluating the risk of triggering (or inception) of liquefaction",
in Geotechnical earthquake engineering; short course, San Diego, California,
April 8-9.
Sowers and Sowers, 1979, Unified soil classification system (After U. S. Waterways
Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics,
New York.
State of California, 2016, Civil Code, Sections 895 et seq.
State of California Department of Transportation, Division of Engineering Services,
Materials Engineering, and Testing Services, Corrosion Technology Branch, 2003,
Corrosion Guidelines, Version 1.0, dated September.
Studio 4, 2016, "New Multi-Family Residence at 906 Ave - Carlsbad, CA 92008", 6 sheets,
dated May 19.
Tan, S.S., and Giffen, D.G., 1995, Landslide hazards in the northern part of the San Diego
Metropolitan area, San Diego County, California, Landslide hazard identification
map no. 35, Plate 35G, Department of Conservation, Division of Mines and Geology,
DMG Open File Report 95-04.
United States Geological Survey, 2014, U.S. Seismic design maps, earthquake hazards
program, http://geohazards.usgs.gov/designmaps/us/application.php.
Version 3.1.0, dated July.
Richard Smerud Appendix A
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APPENDIX B
BORING LOGS
GeoSoils, Inc.
APPENDIX C
SEISMICITY
GeoSoils, Inc.
7099- EQF . OUT. TXT
**********************
* *
* E Q F A U L T *
* *
* Version 3.00 *
* *
DETERMINISTIC ESTIMATION OF
PEAK ACCELERATION FROM DIGITIZED FAULTS
JOB NUMBER: 7099-A-SC
DATE: 06-29-2016
JOB NAME: SMERUD
CALCULATION NAME: 7099 EQF
FAULT-DATA-FILE NAME: C:\Program Fi1es\EQFAULT1\CDMGFLTE.DAT
SITE COORDINATES:
SITE LATITUDE: 33.1601
SITE LONGITUDE: 117.3428
SEARCH RADIUS: 62.4 mi
ATTENUATION RELATION: 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. .Soil-Cor.
UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0
DISTANCE MEASURE: cdist
SCOND: 1
Basement Depth: .01 km Campbell SSR: 0 Campbell SHR: 0
COMPUTE PEAK HORIZONTAL ACCELERATION
FAULT-DATA FILE USED: C:\Program Files\EQFAULT1\CDMGFLTE.DAT
MINIMUM DEPTH VALUE (km): 3.0
Page 1
W.O. 7099-A-SC
PLATE C-I
7099-EQF.OUT.TXT
---------------
EQFAULT SUMMARY ---------------
-----------------------------
DETERMINISTIC SITE PARAMETERS -----------------------------
Page 1
I IESTIMATED MAX. EARTHQUAKE EVENT
I APPROXIMATE I-------------------------------
ABBREVIATED DISTANCE I MAXIMUM I PEAK lEST. SITE
FAULT NAME ml (km) IEARTHQUAKEI SITE IINTENSITY
--------------------------------------I _:__ I
ROSE CANYON 5.3( 8.5) 6.9 0.556 I X
NEWPORT-INGLEWOOD (Offshore) 5.3( 8.6) 6.9 0.552 I X
CORONADO BANK 21.2( 34.1) 7.4 0.238. I IX
ELSINORE-TEMECULA 24.0( 38.7) 6.8 0.140 I VIII
ELSINORE-JULIAN 24.4( 39.2) 7.1 0.170 I VIII
ELSINORE-GLEN IVY 33.4( 53.8) 6.8 0.100 I VII
PALOS VERDES 35.5( 57.2) 7.1 0.115 I VII
EARTHQUAKE VALLEY 44.1( 71.0) 6.5 0.061 VI
NEWPORT-INGLEWOOD (L.A.Basin) 45.7( 73.5) 6.9 0.077 VII
SAN ]ACINTO-ANZA 46.6( 75.0) 7.2 0.093 I VII
SAN JACINTO-SAN JACINTO VALLEY 47.0( 75.7) 6.9 0.075 I VII
CHINO-CENTRAL AVE. (Elsinore) 47.4( 76.3) 6.7 0.091 I VII
WHITTIER 50.9( 81.9) 6.8 0.064 I VI
SAN JACINTO-COYOTE CREEK 52.5( 84.5) 6.8 0.062 I VI
COMPTON THRUST 55.4( 89.1) 6.8 0.084 I VII
ELYSIAN PARK THRUST 58.3( 93.8) 6.7 0.074 I VII
ELSINORE-COYOTE MOUNTAIN 58.3( 93.9) 6.8 0.056 I VI
SAN JACINTO-SAN BERNARDINO 59.5( 95.7) 6.7 0.051 I VI ** * * * * * *
-END OF SEARCH- 18 FAULTS FOUNC I WITHIN THE SPI ECIFIED SEAl CH RADIUS.
THE ROSE CANYON FAULT IS CLOSEST TO THE SITE.
IT IS ABOUT 5.3 MILES (8.5 km) AWAY.
LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.5555 g
Page 2
W.O. 7099-A-SC
PLATE C-2
7099-EQS.OUT.TXT
* * * * **
* *
* E Q S E A R C H *
* *
Version 3.00 *
* *
** * * * * * * * * * ******* **
ESTIMATION OF
PEAK ACCELERATION FROM
CALIFORNIA EARTHQUAKE CATALOGS
JOB NUMBER: 7099-A-Sc
DATE: 06-29-2016
JOB NAME: SMERUD
EARTHQUAKE-CATALOG-FILE NAME: C:\PrograM Fl 1 eS\EQSEARCH\ALLQUAKE .DAT
MAGNITUDE RANGE:
MINIMUM MAGNITUDE: 5.00
MAXIMUM MAGNITUDE: 9.00
SITE COORDINATES:
SITE LATITUDE: 33.1601
SITE LONGITUDE: 117.3428
SEARCH DATES:
START DATE: 1800
END DATE: 2016
SEARCH RADIUS:
62.4 ml
100.4 km
ATTENUATION RELATION: 11) Bozorgnla Campbell Niazi (1999) Hor.-Pleist. Soil-Cor.
UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0
ASSUMED SOURCE TYPE: SS [SS=Strike-slip, DS=Reverse-slip, BT=Blind-thrust]
SCOND: 1 Depth Source: A
Basement Depth: .01 km Campbell SSR: 0 Campbell SHR: 0
COMPUTE PEAK HORIZONTAL ACCELERATION
MINIMUM DEPTH VALUE (km): 3.0
Page 1
W.O. 7099-A-SC
PLATE C-9
7099-EQS.OUT.TXT
-------------------------
EARTHQUAKE SEARCH RESULTS -------------------------
Page 1
I I I TIME I I I SITE ISITEl APPROX.
FILE I LAT. I LONG. I DATE I (LJTC) IDEPTHIQUAKEI ACC. I MM I DISTANCE
CODEI NORTH I WEST I I H M Secl (km)l MAG.I g IINT.l ml [km]
----+-------+--------+----------+--------+-----+-----+-------+----+------------
DMG I33.00001117.3000111/22/180012130 0.01 0.01 6.501 0.243 I IX I 11.3( 18.2)
MGI I33.00001117.0000109/21/18561 730 0.01 0.01 5.001 0.048 I VI I 22.7( 36.5)
MGI I32.80001117.1000105/25/1803 0 0 0.01 0.01 5.001 0.038 I V I 28.6( 46.0)
DMG 132.70001117.2000105/27/1862 20 0 0.01 0.01 5.901 0.057 I VI I 32.8( 52.8)
PAS 132.97101117.8700107/13/198611347 8.21 6.01 5.301 0.039 I V I 33.2( 53.4)
T-A 132.67001117.1700110/21/18621 0 0 0.01 0.01 5.001 0.031 I V I 35.3( 56.8)
T-A 132.67001117.1700112/00/18561 0 0 0.01 0.01 5.001 0.031 I V I 35.3( 56.8)
T-A 132.67001117.1700105/24/18651 0 0 0.01 0.01 5.001 0.031 I V I 35.3( 56.8)
DMG I33.20001116.7000101/01/19201 235 0.0 0.01 5.001 0.029 V I 37.2( 59.9)
DMG I33.70001117.4000105/13/1910 620 0.0 0.01 5.001 0.029 V I 37.4( 60.2)
DMG 133.70001117.4000105/15/191011547 0.0 0.01 6.001 0.053 VI I 37.4( 60.2)
DMG I33.70001117.4000104/11/19101 757 0.01 0.01 5.001 0.029 V I 37.4( 60.2)
DMG I33.69901117.5110I05/31/19381 83455.41 10.01 5.501 0.037 I V I 38.4( 61.9)
DMG I32.80001116.8000110/23/1894123 3 0.01 0.01 5.701 0.041 I V I 40.1( 64.5)
MGI I33.20001116.6000110/12/192011748 0.01 0.01 5.301 0.030 I V I 43.0( 69.2)
DMG I33.71001116.9250109/23/19631144152.61 16.51 5.001 0.024 I IV 45.0( 72.3)
DMG I33.75001117.0000106/06/191812232 0.01 0.01 5.001 0.024 I IV 1 45.3( 72.8)
DMG 133.75001117.0000104/21/19181223225.0I 0.01 6.801 0.073 I VIII 45.3( 72.8)
MGI 133.80001117.6000104/22/191812115 0.01 0.01 5.001 0.023 I IV I 46.6( 75.0)
DMG I33.57501117.9830103/11/1933 518 4.01 0.01 5.201 0.026 I V I 46.7( 75.2)
DMG I33.61701117.9670103/11/1933 154 7.81 0.01 6.301 0.049 I VI I 47.9( 77.0)
DMG I33.80001117.0000I12/25/189911225 0.01 0.01 6.401 0.052 I VI I 48.4( 77.9)
DMG I33.61701118.0170103/14/1933119 150.01 0.01 5.101 0.022 I IV I 50.1( 80.6)
DMG I33.90001117.2000112/19/18801 0 0 0.01 0.01 6.001 0.037 I V I 51.7( 83.3)
PAS I33.50101116.5130102/25/19801104738.SI 13.61 5.501 0.027 I V I 53.3( 85.8)
POP I33.50801116.5140110/31/20011075616.61 15.01 5.101 0.021 I IV I 53.5( 86.1)
DMG I33.00001116.4330106/04/194011035 8.31 0.01 5.101 0.021 I IV I 53.8( 86.5)
DMG I33.50001116.5000109/30/19161 211 0.01 0.01 5.00 0.020 I IV I 54.0( 86.9)
DMG I33.68301118.0500103/11/19331 658 3.01 0.01 5.50 0.026 I V I 54.4( 87.6)
DMG I33.70001118.0670103/11/19331 51022.01 0.01 5.101 0.020 I IV I 56.0( 90.0)
DMG I33.70001118.0670103/11/19331 85457.01 0.01 5.101 0.020 I IV I 56.0( 90.0)
DMG I34.00001117.2500107/23/19231 73026.01 0.01 6.251 0.039 I V I 58.2( 93.7)
MGI I34.00001117.5000112/16/1858110 0 0.01 0.01 7.001 0.064 I VI I 58.7( 94.4)
DMG I33.34301116.3460104/28/19691232042.91 20.01 5.801 0.029 I V I 58.9( 94.8)
DMG I33.75001118.0830103/11/19331 323 0.01 0.01 5.001 0.018 I IV I 59.0( 94.9)
DMG I33.75001118.0830103/13/19331131828.0I 0.01 5.301 0.021 I IV I 59.0( 94.9)
DMG I33.75001118.0830103/11/19331 910 0.01 0.01 5.101 0.019 I IV I 59.0( 94.9)
DMG I33.75001118.0830103/11/19331 2 9 0.01 0.01 5.001 0.018 I IV I 59.0( 94.9)
DMG I33.75001118.0830103/11/19331 230 0.01 0.01 5.101 0.019 I IV I 59.0( 94.9)
DMG I33.95001116.8500109/28/19461 719 9.01 0.01 5.001 0.017 I IV I 61.5( 98.9)
-END OF SEARCH- 40 EARTHQUAKES FOUND WITHIN THE SPECIFIED SEARCH AREA.
Page 2
W.O. 7099-A-SC
PLATE C-b
7099-EQS.OUT.TxT
TIME PERIOD OF SEARCH: 1800 To 2016
LENGTH OF SEARCH TIME: 217 years
THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 11.3 MILES (18.2 km) AWAY.
LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 7.0
LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0.243 g
COEFFICIENTS FOR .GUTENBERG & RICHTER RECURRENCE RELATION:
a-value= 0.888
b-value= 0.371
beta-value= 0.854
------------------------------------
TABLE OF MAGNITUDES AND EXCEEDANCES: ------------------------------------
Earthquake I Number of Times I Cumulative
Magnitude I Exceeded I NO. / Year +-----------------+------------
4.0 I 40 I 0.18433
4.5 I 40 I 0.18433
5.0 I 40 I 0.18433
5.5 I 14 I 0.06452
6.0 8 I 0.03687
6.5 3 0.01382
7.0 I 1 I 0.00461
Page 3
W.O. 7099-A-SC
PLATE C-Il
APPENDIX D
LABORATORY RESULTS
GeoSoils, Inc.
CL CH , ,
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20 40 60 80 100
LIQUID LIMIT
Sample I Depth/El. I LL I PL I P1 I Fines I Classification
101 B-2 1 5.0 24 15 9 1 Silty Fine Sand (ML]
GeoSoils, Inc.
5741 Palmer Way
Carlsbad, CA 92010
Telephone: 760-438-3155
Fax: 760-931-0915
ATTERBERG LIMITS' RESULTS
Project: SMERUD
Number: 7099-A-SC
Date: August 2016 Figure: D - 1
6C
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4.0 -
4.5
5.0
5.5 _______ -____
100 1,000
_______ ____ 10,000
STRESS, psf
GeoSoils, inc. CONSOLIDATION TEST
5741 Palmer Way Project: SMERUD
-' GeoSofli, Ida. Carlsbad CA 92010 £ Telephone: 760-438-3155 Number: 7099-A-SC
Fax: 760-931-0915 Date: August 2016 Figure: D-2
Sample Depth/El. Visual Classifi cation 'Y
Initial
MC
Initial
MC
Final
H20
! B-I 10.0 Silty Sand 125.7 4.5 15.4 1000
0.0
0.5
1.0
1.5
2.0
2.5
3.5
4.0
4.5
5.0
5.51
100 1,000 10,000
STRESS, psi
Cr -
a. CD
CONSOLIDATION TEST eoois, Inc. ________________________________________________
5741 Palmer Way Project: SMERUD
GeosoilS, iñc. Carlsbad, CA 92010 CA ö Telephone: 760-438-3155 Number: 7099-A-SC
Fax: 760-931-0915 ' Date: August 2016 Figure: D-3
Sample Depth/El. Visual Classificatio n Yd
Initial
MC
Initial
MC
Final
H20
! B-2 5.0 Silty Fine Sand [ML) 110.3 5.2 14.6 1000
Cal Land Engineering, Inc.
dba Quartech Consultant
Geotechnical, Environmental, and Civil Engineering
SUMMARY OF LABORATORY TEST DATA
GeoSoils, Inc.
5741 Palmer Way, Suite 0
Carlsbad, CA 92010
W.O. 7099-A-SC
Project Name: SMERUD
Client: N/A
QCI Project No.: 16-029-006k
Date: June 22, 2016
Summarized by: JT
Corrosivity Test Results
.
Sample PH Chloride Sulfate
CT-417- Resistivity
Sample ID Depth CT-532 CT-422 % By CT-532 (643)
(ft)
(643) (ppm) Weight
(ohm-cm)
B-1 2' 5.14 156 0.0152 4200
W.O. 7099-A-SC
FIGURE D-4
576 East Lambert Road, Brea, California 92821; Tel: 714-671-1050; Fax: 714-671-1090
APPENDIX E
GENERAL EARTHWORK AND GRADING GUIDELINES
Geooi1s, Inc.
GENERAL EARTHWORK GRADING GUIDELINES, AND PRELIMINARY CRITERIA
General
These guidelines present general procedures and requirements for earthwork and grading
as shown on the approved grading plans, including preparation of areas to be filled,
placement of fill, installation of subdrains, excavations, and appurtenant structures or
flatwork. The recommendations contained in the geotechnical report are part of these
earthwork and grading guidelines and would supercede the provisions contained hereafter
in the case of conflict. Evaluations performed by the consultant during the course of
grading may result in new or revised recommendations which could supercede these
guidelines or the recommendations contained in the geotechnical report. Generalized
details follow this text.
The contractor is responsible for the satisfactory completion of all earthwork in accordance
with provisions of the project plans and specifications and latest adopted code. In the case
of conflict, the most onerous provisions shall prevail. The project geotechnical engineer
and engineering geologist (geotechnical consultant), and/or their representatives, should
provide observation and testing services, and geotechnical consultation during the
duration of the project.
EARTHWORK OBSERVATIONS AND TESTING
Geotechnical Consultant
Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer
and engineering geologist) should be employed for the purpose of observing earthwork
procedures and testing the fills for general conformance with the recommendations of the
geotechnical report(s), the approved grading plans, and applicable grading codes and
ordinances.
The geotechnical consultant should provide testing and observation so that an evaluation
may be made that the work is being accomplished as specified. It is the responsibility of
the contractor to assist the consultants and keep them apprised of anticipated work
schedules and changes, so that they may schedule their personnel accordingly.
All remedial removals, clean-outs, prepared ground to receive fill, key excavations, and
subdrain installation should be observed and documented by the geotechnical consultant
prior to placing any fill. It is the contractor's responsibility to notify the geotechnical
consultant when such areas are ready for observation.
Laboratory and Field Tests
Maximum dry density tests to determine the degree of compaction should be performed
in accordance with American Standard Testing Materials test method ASTM designation
D-1557. Random or representative field compaction tests should be performed in
GeoSoils, Inc.
accordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017,
at intervals of approximately ±2 feet of fill height or approximately every 1,000 cubic yards
placed. These criteria would vary depending on the soil conditions and the size of the
project. The location and frequency of testing would be at the discretion of the
geotechnical consultant.
Contractor's Responsibility
All clearing, site preparation, and earthwork performed on the project should be conducted
by the contractor, with observation by a geotechnical consultant, and staged approval by
the governing agencies, as applicable. It is the contractor's responsibility to prepare the
ground surface to receive the fill, to the satisfaction of the geotechnical consultant, and to
place, spread, moisture condition, mix, and compact the fill in accordance with the
recommendations of the geotechnical consultant. The contractor should also remove all
non-earth material considered unsatisfactory by the geotechnical consultant.
Notwithstanding the services provided by the geotechnical consultant, it is the sole
responsibility of the contractorto provide adequate equipment and methods to accomplish
the earthwork in strict accordance with applicable grading guidelines, latest adopted codes
or agency ordinances, geotechnical report(s), and approved grading plans. Sufficient
watering apparatus and compaction equipment should be provided by the contractor with
due consideration for the fill material, rate of placement, and climatic conditions. If, in the
opinion of the geotechnical consultant, unsatisfactory conditions such as questionable
weather, excessive oversized rock or deleterious material, insufficient support equipment,
etc., are resulting in a quality of work that is not acceptable, the consultant will inform the
contractor, and the contractor is expected to rectify the conditions, and if necessary, stop
work until conditions are satisfactory.
During construction, the contractor shall properly grade all surfaces to maintain good
drainage and prevent ponding of water. The contractor shall take remedial measures to
control surface water and to prevent erosion of graded areas until such time as permanent
drainage and erosion control measures have been installed.
SITE PREPARATION
All major vegetation, including brush, trees, thick grasses, organic debris, and other
deleterious material, should be removed and disposed of off-site. These removals must
be concluded prior to placing fill. In-place existing fill, soil, alluvium, colluvium, or rock
materials, as evaluated by the geotechnical consultant as being unsuitable, should be
removed prior to any fill placement. Depending upon the soil conditions, these materials
may be reused as compacted fills. Any materials incorporated as part of the compacted
fills should be approved by the geotechnical consultant.
Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic
tanks, wells, pipelines, or other structures not located prior to grading, are to be removed
Richard Smerud Appendix E
Fi1e:e:\wp12\7000\7099a.pge CveoSoUs, Inc. Page 2
or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy,
highly fractured, or otherwise unsuitable ground, extending to such a depth that surface
processing cannot adequately improve the condition, should be overexcavated down to
firm ground and approved by the geotechnical consultant before compaction and filling
operations continue. Overexcavated and processed soils, which have been properly
mixed and moisture conditioned, should be re-compacted to the minimum relative
compaction as specified in these guidelines.
Existing ground, which is determined to be satisfactory for support of the fills, should be
scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical
consultant. After the scarified ground is brought to optimum moisture content, or greater
and mixed, the materials should be compacted as specified herein. If the scarified zone
is greater than 6t0 8 inches in depth, it may be necessary to remove the excess and place
the material in lifts restricted to about 6 to 8 inches in compacted thickness.
Existing ground which is not satisfactory to support compacted fill should be
overexcavated as required in the geotechnical report, or by the on-site geotechnical
consultant. Scarification, disc harrowing, or other acceptable forms of mixing should
continue until the soils are broken down and free of large lumps or clods, until the working
surface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or other
uneven features, which would inhibit compaction as described previously.
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical
[h:v]), the ground should be stepped or benched. The lowest bench, which will act as a
key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm
material, and approved by the geotechnical consultant. In fill-over-cut slope conditions,
the recommended minimum width of the lowest bench or key is also 15 feet, with the key
founded on firm material, as designated by the geotechnical consultant. As a general rule,
unless specifically recommended otherwise by the geotechnical consultant, the minimum
width of fill keys should be equal to 1/2 the height of the slope.
Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable
material. Benching may be used to remove unsuitable materials, although it is understood
that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered
for unsuitable materials in excess of 4 feet in thickness.
All areas to receive fill, including processed areas, removal areas, and the toes of fill
benches, should be observed and approved by the geotechnical consultant prior to
placement of fill. Fills may then be properly placed and compacted until design grades
(elevations) are attained.
COMPACTED FILLS
Any earth materials imported or excavated on the property may be utilized in the fill
provided that each material has been evaluated to be suitable by the geotechnical
Richard Smerud Appendix E
Fi1e:e:\wp12\7000\7099a.pge GeoSoils, Inc. Page 3
consultant. These materials should be free of roots, tree branches, other organic matter,
or other deleterious materials. All unsuitable materials should be removed from the fill as
directed by the geotechnical consultant. Soils of poor gradation, undesirable expansion
potential, or substandard strength characteristics may be designated by the consultant as
unsuitable and may require blending with other soils to serve as a satisfactory fill material.
Fill materials derived from benching operations should be dispersed throughout the fill
area and blended with other approved material. Benching operations should not result in
the benched material being placed only within a single equipment width away from the
fill/bedrock contact.
Oversized materials defined as rock, or other irreducible materials, with a maximum
dimension greater than 12 inches, should not be buried or placed in fills unless the
location of materials and disposal methods are specifically approved by the geotechnical
consultant. Oversized material should be taken offsite, or placed in accordance with
recommendations of the geotechnical consultant in areas designated as suitable for rock
disposal. GSI anticipates that soils to be utilized as fill material for the subject project may
contain some rock. Appropriately, the need for rock disposal may be necessary during
grading operations on the site. From a geotechnical standpoint, the depth of any rocks,
rock fills, or rock blankets, should be a sufficient distance from finish grade. This depth is
generally the same as any overexcavation due to cut-fill transitions in hard rock areas, and
generally facilitates the excavation of structural footings and substructures. Should deeper
excavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas,
etc.), the developer may consider increasing the hold-down depth of any rocky fills to be
placed, as appropriate. In addition, some agencies/jurisdictions mandate a specific
hold-down depth for oversize materials placed in fills. The hold-down depth, and potential
to encounter oversize rock, both within fills, and occurring in cut or natural areas, would
need to be disclosed to all interested/affected parties. Once approved by the governing
agency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in fills on this
project is provided as 10 feet, unless specified differently in the text of this report. The
governing agency may require that these materials need to be deeper, crushed, or
reduced to less than 12 inches in maximum dimension, at their discretion.
To facilitate future trenching, rock (or oversized material), should not be placed within the
hold-down depth feetfrom finish grade, the range of foundation excavations, future utilities,
or underground construction unless specifically approved by the governing agency, the
geotechnical consultant, and/or the developer's representative.
If import material is required for grading, representative samples of the materials to be
utilized as compacted fill should be analyzed in the laboratory by the geotechnical
consultant to evaluate it's physical properties and suitability for use onsite. Such testing
should be performed three (3) days prior to importation. If any material other than that
previously tested is encountered during grading, an appropriate analysis of this material
should be conducted by the geotechnical consultant as soon as possible.
Richard Smerud Appendix E
Fi1e:e:\wp12\7000\7099a.pge GeoSoils, Inc. Page 4
Approved fill material should be placed in areas prepared to receive fill in near horizontal
layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The
geotechnical consultant may approve thick lifts if testing indicates the grading procedures
are such that adequate compaction is being achieved with lifts of greater thickness. Each
layer should be spread evenly and blended to attain uniformity of material and moisture
suitable for compaction.
Fill layers at a moisture content less than optimum should be watered and mixed, and wet
fill layers should be aerated by scarification, or should be blended with drier material.
Moisture conditioning, blending, and mixing of the fill layer should continue until the fill
materials have a uniform moisture content at, or above, optimum moisture.
After each layer has been evenly spread, moisture conditioned, and mixed, it should be
uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by
ASTM test designation D-1557, or as otherwise recommended by the geotechnical
consultant. Compaction equipment should be adequately sized and should be specifically
designed for soil compaction, or of proven reliability to efficiently achieve the specified
degree of compaction.
Where tests indicate that the density of any layer of fill, or portion thereof, is below the
required relative compaction, or improper moisture is in evidence, the particular layer or
portion shall be re-worked until the required density and/or moisture content has been
attained. No additional fill shall be placed in an area until the last placed lift of fill has been
tested and found to meet the density and moisture requirements, and is approved by the
geotechnical consultant.
In general, per the latest adopted version of the California Building Code (CBC), fill slopes
should be designed and constructed at a gradient of 2:1 (h:v), or flatter. Compaction of
slopes should be accomplished by over-building a minimum of 3 feet horizontally, and
subsequently trimming back to the design slope configuration. Testing shall be performed
as the fill is elevated to evaluate compaction as the fill core is being developed. Special
efforts may be necessary to attain the specified compaction in the fill slope zone. Final
slope shaping should be performed by trimming and removing loose materials with
appropriate equipment. A final evaluation of fill slope compaction should be based on
observation and/or testing of the finished slope face. Where compacted fill slopes are
designed steeper than 2:1 (h:v), prior approval from the governing agency, specific
material types, a higher minimum relative compaction, special reinforcement, and special
grading procedures will be recommended.
If an alternative to over-building and cutting back the compacted fill slopes is selected,
then special effort should be made to achieve the required compaction in the outer 10 feet
of each lift of fill by undertaking the following:
1. An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot
should be used to roll (horizontal) parallel to the slopes continuously as fill is
placed. The sheepsfoot roller should also be used to roll perpendicular to the
Richard Smerud Appendix E
Fi1e:e:\wp12\7000\7099a.pge GeoSodS Inc. Page 5
slopes, and extend out over the slope to provide adequate compaction to the face
of the slope.
Loose fill should not be spilled out over the face of the slope as each lift is
compacted. Any loose fill spilled over a previously completed slope face should be
trimmed off or be subject to re-rolling.
Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of the
slope at appropriate vertical intervals, subsequent to compaction operations.
After completion of the slope, the slope face should be shaped with a small tractor
and then re-rolled with a sheepsfoot to achieve compaction to near the slope face.
Subsequent to testing to evaluate compaction, the slopes should be grid-rolled to
achieve compaction to the slope face. Final testing should be used to evaluate
compaction after grid rolling.
Where testing indicates less than adequate compaction, the contractor will be
responsible to rip, water, mix, and recompact the slope material as necessary to
achieve compaction. Additional testing should be performed to evaluate
compaction.
SUBDRAIN INSTALLATION
Subdrains should be installed in approved ground in accordance with the approximate
alignment and details indicated by the geotechnical consultant. Subdrain locations or
materials should not be changed or modified without approval of the geotechnical
consultant. The geotechnical consultant may recommend and direct changes in subdrain
line, grade, and drain material in the field, pending exposed conditions. The location of
constructed subdrains, especially the outlets, should be recorded/surveyed by the project
civil engineer. Drainage at the subdrain outlets should be provided by the project civil
engineer.
EXCAVATIONS
Excavations and cut slopes should be examined during grading by the geotechnical
consultant. If directed by the geotechnical consultant, further excavations or
overexcavation and refilling of cut areas should be performed, and/or remedial grading of
cut slopes should be performed. When fill-over-cut slopes are to be graded, unless
otherwise approved, the cut portion of the slope should be observed by the geotechnical
consultant prior to placement of materials for construction of the fill portion of the slope.
The geotechnical consultant should observe all cut slopes, and should be notified by the
contractor when excavation of cut slopes commence.
Richard Smerud Appendix E
File:e:\wpl2\7000\7099a.pge GeoSoils, Inc. Page 6
If, during the course of grading, unforeseen adverse or potentially adverse geologic
conditions are encountered, the geotechnical consultant should investigate, evaluate, and
make appropriate recommendations for mitigation of these conditions. The need for cut
slope buttressing or stabilizing should be based on in-grading evaluation by the
geotechnical consultant, whether anticipated or not.
Unless otherwise specified in geotechnical and geological report(s), no cut slopes should
be excavated higher or steeper than that allowed by the ordinances of controlling
governmental agencies. Additionally, short-term stability of temporary cut slopes is the
contractor's responsibility.
Erosion control and drainage devices should be designed by the project civil engineer and
should be constructed in compliance with the ordinances of the controlling governmental
agencies, and/or in accordance with the recommendations of the geotechnical consultant.
COMPLETION
Observation, testing, and consultation by the geotechnical consultant should be
conducted during the grading operations in order to state an opinion that all cut and fill
areas are graded in accordance with the approved project specifications. After completion
of grading, and after the geotechnical consultant has finished observations of the work,
final reports should be submitted, and may be subject to review by the controlling
governmental agencies. No further excavation or filling should be undertaken without prior
notification of the geotechnical consultant or approved plans.
All finished cut and fill slopes should be protected from erosion and/or be planted in
accordance with the project specifications and/or as recommended by a landscape
architect. Such protection and/or planning should be undertaken as soon as practical after
completion of grading.
JOB SAFETY
General
At GSI, getting the job done safely is of primary concern. The following is the company's
safety considerations for use by all employees on multi-employer construction sites.
On-ground personnel are at highest risk of injury, and possible fatality, on grading and
construction projects. GSI recognizes that construction activities will vary on each site, and
that site safety is the prime responsibility of the contractor; however, everyone must be
safety conscious and responsible at all times. To achieve our goal of avoiding accidents,
cooperation between the client, the contractor, and GSI personnel must be maintained.
Richard Smerud Appendix E
File:e:\wpl2\7000\7099a.pge Gvoftilsq Inc. Page 7
In an effort to minimize risks associated with geotechnical testing and observation, the
following precautions are to be implemented for the safety of field personnel on grading
and construction projects:
Safety Meetings: GSI field personnel are directed to attend contractor's regularly
scheduled and documented safety meetings.
Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel,
at all times, when they are working in the field.
Safety Flags: Two safety flags are provided to GSI field technicians; one is to be
affixed to the vehicle when on site, the other is to be placed atop the
spoil pile on all test pits.
Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing
amber beacons, or strobe lights, on the vehicle during all field testing.
While operating a vehicle in the grading area, the emergency flasher
on the vehicle shall be activated.
In the event that the contractor's representative observes any of our personnel not
following the above, we request that it be brought to the attention of our office.
Test Pits Location, Orientation, and Clearance
The technician is responsible for selecting test pit locations. A primary concern should be
the technician's safety. Efforts will be made to coordinate locations with the grading
contractor's authorized representative, and to select locations following or behind the
established traffic pattern, preferably outside of current traffic. The contractor's authorized
representative (supervisor, grade checker, dump man, operator, etc.) should direct
excavation of the pit and safety during the test period. Of paramount concern should be
the soil technician's safety, and obtaining enough tests to represent the fill.
Test pits should be excavated so that the spoil pile is placed away from oncoming traffic,
whenever possible. The technician's vehicle is to be placed next to the test pit, opposite
the spoil pile. This necessitates the fill be maintained in a driveable condition.
Alternatively, the contractor may wish to park a piece of equipment in front of the test
holes, particularly in small fill areas or those with limited access.
A zone of non-encroachment should be established for all test pits. No grading equipment
should enter this zone during the testing procedure. The zone should extend
approximately 50 feet outward from the center of the test pit. This zone is established for
safety and to avoid excessive ground vibration, which typically decreases test results.
When taking slope tests, the technician should parkthe vehicle directly above or belowthe
test location. If this is not possible, a prominent flag should be placed at the top of the
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slope. The contractors representative should effectively keep all equipment at a safe
operational distance (e.g., 50 feet) away from the slope during this testing.
The technician is directed to withdraw from the active portion of the fill as soon as possible
following testing. The technician's vehicle should be parked at the perimeter of the fill in
a highly visible location, well away from the equipment traffic pattern. The contractor
should inform our personnel of all changes to haul roads, cut and fill areas or other factors
that may affect site access and site safety.
In the event that the technician's safety is jeopardized or compromised as a result of the
contractor's failure to comply with any of the above, the technician is required, by company
policy, to immediately withdraw and notify his/her supervisor. The grading contractor's
representative will be contacted in an effort to affect a solution. However, in the interim,
no further testing will be performed until the situation is rectified. Any fill placed can be
considered unacceptable and subject to reprocessing, recompaction, or removal.
In the event that the soil technician does not comply with the above or other established
safety guidelines, we request that the contractor bring this to the technician's attention and
notify this office. Effective communication and coordination between the contractor's
representative and the soil technician is strongly encouraged in order to implement the
above safety plan.
Trench and Vertical Excavation
It is the contractor's responsibility to provide safe access into trenches where compaction
testing is needed. Our personnel are directed not to enter any excavation or vertical cut
which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of
instability, has any loose rock or other debris which could fall into the trench; or 3) displays
any other evidence of any unsafe conditions regardless of depth.
All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters,
should be shored or laid back. Trench access should be provided in accordance with
Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any
trench by being lowered or "riding down" on the equipment.
If the contractor fails to provide safe access to trenches for compaction testing, our
company policy requires that the soil technician withdraw and notify his/her supervisor.
The contractor's representative will be contacted in an effort to affect a solution. All backfill
not tested due to safety concerns or other reasons could be subject to reprocessing and/or
removal.
If GSI personnel become aware of anyone working beneath an unsafe trench wall or
vertical excavation, we have a legal obligation to put the contractor and owner/developer
on notice to immediately correct the situation. If corrective steps are not taken, GSI then
has an obligation to notify Cal/OSHA and/or the proper controlling authorities.
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Natural grade
Proposed pad grade
I -
LIII I va T'
Subgrade at 2 percent gradient draining toward street
Bedrock or
approved native
material
Typical benching
overexcavate and recompact
per text of report
CUT LOT OR MATERIAL-TYPE TRANSITION
Natural grade
I
Proposed pad grade
— — — I
tent. draining toward street
3- to 7-foot minimum. —J
overexcavate and reconipact
per text of report
Deeper overexcavation may be
recommended by the geotechnical
consultant in steep cut-fill transition
areas, such that the underlying
Typical benching material topography is no steeper than 3:1 (H:V)
(4-foot minimum)
CUT-FILL LOT (DAYLIGHT TRANSITION)
QWjnc. TRANSITION LOT DETAILS Plate E-12
Bedrock or
approved native