HomeMy WebLinkAboutCT 2022-0001; HOPE APARTMENTS; RESPONSE TO COMMENTS AND PRELIMINARY GEOTECHNICAL EVALUATION PROPOSED HOPE APARTMENTS; 2024-04-04
GEOTECHNICAL | ENVIRONMENTAL | MATERIAL
April 4, 2024
Project No. 3780-SD
Wermers Companies
5120 Shoreham Place, Suite 150
San Diego, CA 92122
Attention: Mr. Patrick Zabrocki
Subject: Response to City Review Comments
APN 203-320-20, -02, -48, -51, 40, and -41
Carlsbad Village Drive and Hope Avenue
Carlsbad, California 92008
Dear Mr. Zabrocki:
INTRODUCTION
GeoTek, Inc. (GeoTek) was requested to respond to City of Carlsbad Geotechnical Report Review
Comments, their Project ID CT2022-0001, grading Permit No. GR2023-0044, 1st Review. For
convenience a repruction of the review comment and number is presented in itilacs, followed by GeoTek’s
response. A copy of the review comments is presented in Appendix A.
Comment No. 1
The submitted "Preliminary Geotechnical Evaluation ..." by GeoTek, Inc. is approximately 1-1/2 years old,
addresses an antiquated code cycle (2019 California Building Code), is marked "Draft", and is not
signed/stamped by the report authors. Consequently, please review the most current revision of the
grading and foundation plans for the proposed apartment project and provide a complete wet-signed
copy of an updated geotechnical report that is not marked "Draft," is signed/stamped by the report
authors, addresses the current scope of the proposed four-level apartment with subterranean parking
structure development, and addresses the currently adopted 2022 California Building Code.
Response to Comment No. 1
A preliminary geotechnical report prepared by the authors, was completed July 28, 2022. A copy
of the report is provided in Appendix B. GeoTek has been retained for the design phase of the
GeoTek, Inc.
1384 Poinsettia Avenue, Suite A Vista, CA 9208 1-8505
(760) 599-0509 Office (760) S99-0593 F~ www.geotekusa.com
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 2
project and has reviewed project civil and structural plans as planning has progressed. A review
of the current civil plans were reviewed and grossly remain consistent with entitlement plans
from a geotechnical perspective (the project remains to be designed as a 4-story, wood framed,
multi-family building over a two-level subterranean basement podium. The project remains to
be considered geotechnically suitable, provided the recommendations presented by GeoTek are
incorporated into the design and construction phases, as well as those presented or referenced
herein.
It is GeoTek’s understanding that the project was entitled during the California Building Code
2019, however, as planning has progressed, the current code is CBC 2022. The project is
recommended to adhere to geotechnical recommendations presented by GeoTek , the CBC
2022, and the City of Carlsbad. The adoption of the current building code was recommended in
GeoTek’s 2022 report in section 5.2.1.
Comment No. 2
Please provide a statement addressing the potential impact of the proposed project on adjacent off-site
properties from a geotechnical standpoint.
Response to Comment 2.
Considering GeoTek’s response to comment number 15 and provided that the geotechnical
recommendations presented by GeoTek are incorporated into the design and construction
phases of the project, the proposed improvements will not adversely impact offsite existing
improvements.
Comment No. 3
Please provide an updated "Geotechnical Map" utilizing the most current revision of the grading plan for
the project as the base map and at a sufficiently large scale to clearly show (at a minimum): a) existing
site topography, b) proposed apartment/parking structure and improvements, c) proposed finished
grades, d) geologic units, e) locations of proposed shoring and temporary slopes associated with the
subterranean parking level, and f) the locations of subsurface exploration. Please produce the
"Geotechnical Map" at a scale that is sufficiently large to clearly distinguish all topography, text, finish
grades, elevations, etc., and shows all information requested above (an over-size plate will likely be
necessary to increase legibility and show all requested information)
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 3
Response to Comment No. 3
An updated Geotechnical Map is provided as Plate 1 and attached to this response at the rear of
the text.
Comment No. 4
Please provide updated geologic cross-sections A-A' and B-B' based on the updated "Geotechnical Map"
and showing all the information requested in comment #3 above. Please ensure the cross sections show,
along with the items in comment #3 above, a) groundwater measured in the subsurface exploration, b)
the limits of the recommended remedial grading, c) the proposed shoring and temporary slopes, and d)
the adjacent streets/improvements (Grand Avenue, Hope Avenue, parking lot and driveway) that bound
the subject site.
Response to Comment No. 4
An updated Geotechnical Cross Sections are provided as Plate 2 and attached to this response
at the rear of the text.
Comment No. 5
Please provide a discussion addressing the geologic structure (direction/dip of bedding, fracturing, etc.) of
the Old Paralic deposits and Santiago formation bedrock, and the relationship between the structural
geology of the Old Paralic deposits/Santiago formation underlying the site as it relates to the retaining
wall design for the parking level walls (geologic surcharge from bedding, etc.), shoring, and stability of the
proposed 1: 1 (H:V) temporary slopes for the proposed construction.
Response to Comment No. 5
In general, the regional geologic structure of the area is gently dipping to the southwest
approximately 8-12 degrees. However, locally the 2008 Kennedy and Tan 30’x60’ quadrangle
indicates localized Old Paralic Deposits dip to the northeast approximately 8 degrees. GeoTek’s
experience in the area of Carlsbad note an absence of geologic structure in the Quaternary-age
Old Paralic deposits and is considered to be massive, moderately dense, and competent
formational material. Unconformably underlying the Quaternary-age Old Paralic Deposits is the
Tertiary-age Santiago Formation. Geologic maps (Kennedy, 2008) indicate the Santiago formation
gently dips to the southwest approximately 8 degrees. As discussed in GeoTek’s discussion of
the Santiago Fomation (Section 4.2.3). The historic geomorphic evolution of coastal San Diego
County consists of several transgressional wave-cut platforms (terraces) mantled with marine
and non-marine sedimentary deposits (Paralic). Wave-cut platforms consist of a low-lying near
level seat with a steep bench, similar to current day coastal bluffs in the region. The ancient
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 4
shoreline/bluff has been interpreted to transect the site in a general north-south alignment in the
eastern half of the project.
Considering the Old Paralic deposits and the Santiago Formation are massive and the geologic
contact between the two units is generally flat or shallow dipping, reduced soil strengths or
anisotropic stability analysis is not conserved to be representing the geologic model.
Comment No. 6
Please discuss if the subject site is considered a "Near-Fault Site" in accordance with ASCE 7-16 and
provide updated seismic design parameters for the site as necessary to address the 2022 California
Building Code and ASCE 7-16.
Response to Comment No. 6
The subject site is considered a “Near-Fault Site” in accordance with ASCE 7-16 (a Site within
9.5 miles of the surface projection of a known active fault capable of producing Mw7 or larger
events), as with most of coastal San Diego.
GeoTek’s 2022 referenced preliminary report provided seismic design parameters based on 2019
California Building Code and ASCE 7-16. The following table provides seismic design parameters
based on 2022 California Building Code and ASCE 7-16.
The site is located at approximately 33.1632, degrees west latitude and -117.3443 degrees north
longitude. Site spectral accelerations (Ss and S1), for 0.2 and 1.0 second periods for a Class “C”
site, were determined from the web site seismismaps.org, developed by SEAOC and OSHPD
that uses the USGS web services. A Site Class “C” is considered appropriate based on the
paralic deposits. The results, based on ASCE 7-16 and the 2022 CBC, are presented in the
following table:
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 5
SITE SEISMIC PARAMETERS
Mapped 0.2 sec Period Spectral Acceleration,
Ss 1.064
Mapped 1.0 sec Period Spectral Acceleration,
S1 0.385
Site Coefficient, Fa 1.2
Site Coefficient, Fv 1.5
Maximum Considered Earthquake Spectral
Response Acceleration for 0.2 Second, SMS 1.276
Maximum Considered Earthquake Spectral
Response Acceleration for 1.0 Second, SM1 0.578
5% Damped Design Spectral Response
Acceleration Parameter at 0.2 Second, SDS 0.851
5% Damped Design Spectral Response
Acceleration Parameter at 1 second, SD1 0.385
Site Modified Ground Acceleration, PGAM 0.562
Comment No. 7
Given the geotechnical consultants current understanding of the structure associated with the proposed
four-level apartment with subterranean parking development, please revisit and discuss the need for site-
specific ground motion analysis and provide if necessary.
Response to Comment No. 7
Per ASCE/SEI 7-16, Section 11.4.8 Site-Specific Ground Motion Procedures.
“…… A ground motion hazard analysis shall be performed in accordance with Section 21.2 for
the following:
1. seismically isolated structures and structures with damping systems on sites with S1 greater
than or equal to 0.6,
2. structures on Site Class E sites with Ss greater than or equal to 1.0, and.
3. structures on Site Class D and E sites with S1 greater than or equal to 0.2.”
The Subject Site considered to be a Site Class “C” and does not exhibit an S1 value greater than
or equal to 0.6. The Subject Site has an S1 value of 0.385. A site specific ground motion hazard
analysis is not considered a geotechnical recommendation.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 6
Comment No. 8
As the expansion index and sulfate exposure testing presented in the report were both performed on
samples of the existing near surface soils (B-5 @ 0-3), please discuss how the geotechnical engineering
properties of the geologic materials that will be exposed at the depth of the parking level (approximately
18' to 22' below existing grade) were assessed with respect to the foundation design and
expansion/sulfate conditions. Please provide testing/recommendations to address and evaluate these
conditions as necessary.
Response to Comment No. 8
The project is designed with a mat slab with a preliminary thickness of 48 inches thick. The
Santiago Formation near the basement depth was identified as a silty fine sandstone. In addition
the relatively undisturbed direct shear result at Boring B-1 at a depth of 25 feet (elevation of 38
feet msl) indicates granular low cohesive material. A soil/bedrock sample with appreciable
potentially expansive material would have a higher cohesion value on the order of a magnitude 2
to 4 times the cohesive value of the sample tested at 244 psf. We recommend that the basement
level finished subgrade soils expansion potential and sulfate exposure be verified at the time of
excavation.
Comment No. 9
As several options are presented in the report for foundations for the proposed podium structure (post-
tensioned and conventional foundations), please update (based on review of the most current plans) and
clarify the foundation/slab type that is recommended for the proposed structure; and provide any updated
recommendations as necessary to address the current development.
Response to Comment No. 9
The preliminary soil report was prepared during the entitlement phase with various foundation
design options for the design team and stakeholders to evaluate options for potential feasibility
and support of construction design. The project will utilized a mat slab foundation. Redaction or
reduction of preliminary design parameters is not necessary. Supplemental design
recommendations have been provided during progressive design.
Comment No. 10
Please clarify the recommended embedment material (compacted fill, Old Paralic deposits, Santiago
formation) for both the proposed podium structure and at-grade improvements, as it appears the report
currently specifies compacted fill for the proposed foundations.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 7
Response to Comment No. 10
The basement structure shall be founded entirely in undisturbed Santiago Formation. Structural
foundations separated entirely from the podium structure may be founded entirely in engineered
fill or Old Paralic deposits. Where portions of the building that are physically connected or part
of the podium structure have foundations outside the podium structure (leasing office), the
foundations are recommended to be founded on Santiago Formation.
Comment No. 11
As foundation/slab recommendations for soils with both "Very Low" and "Low" expansion potential are
provided in the report, please clarify the methods that are being recommended to address expansive soils
for the "Low" case (El greater than 20). As soils with Expansion Index (El) over 20 are considered
expansive and require mitigation in accordance with Sections 1803.5.3 and 1808.6 of the 2022 CBC,
please provide recommendations to satisfy the 2022 California Building Code. Please provide the Effective
Plasticity Index and any other parameters for slab-on-ground design in accordance with 1808.6.2 and
WRI/CRSI Design of Slab-on-Ground floors or a posttensioned design in accordance with PTI DC 10.5
and provide a statement that the foundation/slab system for the proposed residential structures will meet
the requirements of Section 1808.6 of the 2022 California Building Code.
Response to Comment No. 11
Laboratory testing of the subsurface soils/formational material indicate the site exhibits a Very
Low Expansive potential, however, as Expansion Index testing per ASTM D4283 was not
performed, a Low Expansion design value was provided and considered to be the upper limits of
expansive potential based on GeoTek’s experience in the area and engineering judgement.
Confirmation sampling and evaluation of near rough grade elevations after rough grading has been
performed is recommended. If Low expansive materials are within twelve inches of pad grade,
the subgrade is recommended to be moisture conditioned to 110% of the subgrade’s optimum
moisture content in accordance to ASTM D 1557 test procedures. The basement is considered
to be exempt from moisture conditioning due to the confining weight of the mat slab foundation.
Effective plasticity for conventional footings is presented in Section 5.3.5. Additional soil design
parameters not presented in GeoTek’s 2022 report and within this response to comments letter
is not considered necessary unless specifically requested by a design team member. The
proposed residential structures meet the requirements of Section 1808.6 of the 2022 California
Building Code.
Comment No. 12
Please provide updated recommendations for post-tensioned foundation/slab design as necessary based
the most current edition of "Standard Requirements for Design and Analysis of Shallow of Post-Tensioned
Concrete Foundation ..." PT DC 10.5-19. Please also provide the basis and supporting data for the
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 8
parameters for use in the post-tension slab design (sieve results, percent clay, effective plasticity index,
etc.) as necessary.
Response to Comment No. 12
GeoTek’s reference to PTI 2008, is a typographical reference and should have referenced PT DC
10.5-19. PT design parameters assumed the following values: Thornthwaite Moisture Index = 20;
constant suction value = 3.9pF; post-equilibrium case assumed with wet (swelling) cycle going
from 3.9pF to 3.0pF and drying (shrinking) cycle going from 3.9pF to 4.5pF. PT design is not
planned for the project.
Comment No. 13
As groundwater levels measured during the subsurface exploration are above the elevation of the
excavation for the parking level of the proposed building and will also be encountered during the drilling
for the shoring piles, please discuss the potential impact of groundwater on the proposed construction
(grading to achieve parking level pad grade, drilling for shoring piles and installation of lagging, etc.) and
provide recommendations to address as necessary.
Response to Comment No. 13
The project is planning to dewater the building foundation prior and during construction. A
specialty contractor in dewatering construction should be consulted with for dewatering design
and implementation during construction. If dewatering is not desired prior to cast-in-drilled-hole
(CIDH) soldier piles, the project should anticipate groundwater during excavation of CIDH
soldier piles. The N60 values of the geotechnical borings indicate a very dense Santiago
Formation and the CIDH holes are anticipated to remain open and in a stable condition provided
that the soldier beam and cement-slurry materials (concrete and cement-sand slurry) are
constructed the same day of CIDH excavation. The cement-slurry materials should anticipate
placement by tremie method. As the cement-slurry materials are installed, the groundwater
displaced vertically, will need to be properly extracted, managed, at handled (disposed of)
properly. A pilot/test hole can be performed prior to production to better estimate CIDH
competency.
Comment No. 14
Please provide recommendation for temporary slopes (maximum allowed height of vertical cut, maximum
inclination of sloping cut, etc.) associated with the proposed relatively deep excavations for the parking
level of the building and other site grading activities.
Response to Comment No. 14
Section 5.2.8 of GeoTek’s 2022 report Section 5.2.8 should be superseded by this revised section.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 9
5.2.8 Temporary Basement Excavations
Based on preliminary discussions with the client, a soldier beam and wood lagging with tie-back
anchors are preferred for the basement excavation. A Review of the temporary shoring plan
prepared by Shoring Design, presents a typical section along Grand Avenue with an approximate
temporary excavation slope at an inclination of 1:1 for 8 feet and a cantilevered shoring design
for an additional 17 feet (including the excavation for the mat slab). Considering GeoTek’s
response to comment number 15, this maximum designed profile is considered geotechnically
suitable from a temporary global stability analysis.
It is extremely difficult to predict accurately the amount of deflection of a shored excavation. It
should be realized that some deflection will occur. It is estimated that this deflection may be on
the order of 1-inch at the top of the shored excavation. If greater than expected deflection
occurs during construction, additional bracing may be necessary to minimize adjacent area
settlement. If it is desired to reduce the deflection of the shoring, a greater lateral earth pressure
(such as at-rest earth pressures) may be used in the shoring design with an increased stiffness of
the system.
Soldier pile installations consisting of a concrete encased steel H-beams should be observed by
the project geotechnical consultant to verify excavations are drilled into anticipated conditions,
pile excavations are properly prepared and cleaned out, dimensions are achieved, and specific
installation procedures are followed. The shoring to be constructed at the site should be
surveyed and monitored on a regular basis for any movement. If any significant movement is
observed during shoring and construction operations, it should be brought to the immediate
attention of the project general contractor, shoring contractor and geotechnical consultant for
appropriate corrective measures.
It is recommended that during design of the shoring GeoTek be contacted for review of
geotechnical design parameters.
Comment No. 15
As the current grading plans show approximate 8 to 10' high 1:1 (H:/) temporary slopes extending from
the top of the proposed shoring and up to within 2' of Grand Avenue and other off-site property, please
provide stability analysis of the 1:1 slopes exposing fill/Old Paralic deposits demonstrating the proposed
temporary cuts will be safe for workers and will not adversely impact the city ROW or other offsite
property. Please include potential surcharge loading from emergency vehicle (Fire Truck) in the analysis.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 10
Response to Comment No. 15
GeoTek concurs the profile described in Comment No. 15 represents the most critical
configuration of temporary excavation for the basement. GeoTek performed a global stability
analysis of this section and applied a surcharge for traffic along Hope Avenue to include that of a
fire truck estimated to be a strip load of 300 PSf. Results of the analysis present a factor of safety
of at least 1.5 and 1.1 for static and pseudo static conditions, respectively. A summary output is
presented in Appendix C.
Comment No. 16
Please confirm the 1” deflection of shoring piles discussed in the report will not adversely impact adjacent
offsite property. Please provide the maximum deflection that should be used for shoring design from a
geotechnical standpoint to prevent adverse impacts to adjacent off-site property.
Response to Comment No. 16
The maximum recommended deflection design of 1-inch will not adversely affect adjacent offsite
improvements or property.
Comment No. 17
Please provide the minimum diameter for shoring piles and the depth below the parking level for point
of fixity for the shoring piles from a geotechnical standpoint.
Response to Comment No. 17
For the design of soldier piles, an ultimate lateral bearing value (passive value) of 300 pounds per
square foot per foot of depth, to a maximum value of 4,500 psf for a CIDH minimum diameter
of 24 inches, may be assumed for material below the level of excavation to determine soldier pile
depth and spacing. The effective width of the soldier pile can be assumed to be twice the solder
pile diameter for passive pressure calculations. However, passive resistance should be ignored
within the upper foot due to possible disturbance.
The point of fixity for a shoring pile is a function of the shoring system and is best understood by
the shoring designer.
Comment No. 18
Please provide active earth pressure for the shoring design for the temporary 1:1 (H:V) sloping backfill
condition atop the shoring that is currently proposed for the construction of the subterranean parking
levels of the building.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 11
Response to Comment No. 18
Surface Slope of
Retained Materials
(H:V)
Equivalent Fluid
Pressure
(PCF)
Select Backfill
1:1 90
Comment No. 19
The retaining wall recommendations provided in the report appear to address conventional retaining walls
up to a height of 10' and not specifically the retaining walls (up to approximately 22') placed up against
shoring that are proposed for the subterranean parking levels of the building. Please provide updated
recommendations for the proposed retaining wall associated with the subterranean parking level
(active/at-rest pressures, subdrain system, etc.) as necessary.
Response to Comment No. 19
Please see GeoTek’s Supplemental Geotechnical Recommendations dated October 23, 2023
presented in Appendix D.
Section 5.4.3 of GeoTek’s 2023 Supplemental Geotechnical Recommendations should be
superseded by this revised section.
5.4.3 Seismic Earth Pressures on Retaining Walls
As required by the 2022 CBC, walls with a retained height greater than six feet are required to
include an incremental seismic earth pressure in the wall design. Based upon review, walls with
retained heights of up to approximately 22 feet are planned at the site.
The lateral pressure on retaining walls due to earthquake motions (dynamic lateral force) should
be calculated as PA = 3/8H2kh where
PA = dynamic lateral force (pounds-per-foot)
= unit weight = 127-pounds-per-cubic-foot
H = height of wall (feet)
kh = seismic coefficient = 0.187
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 12
The dynamic lateral force may also be expressed as 18-pounds-per-cubic-foot EFP.
The dynamic lateral force is in addition to the static force and should be applied as an inverted
triangular distribution, with the resultant applied at a height of 2/3H above the base of the wall.
The dynamic lateral force need not be applied to retaining walls 6-feet or less in height.
Restrained retaining walls may be designed for at-rest loading condition or the active and seismic
loading condition combined. Typically, it appears the design of the restrained at-rest condition
for retaining wall loading may be adequate for the seismic design of the retaining walls. However,
the active earth pressure combined with the seismic design load should be reviewed and also
considered in the design of the retaining walls.
Comment No. 20
Please provide recommendations for tieback anchors associated with the shoring system associated with
the parking level of the proposed structure if necessary.
Response to Comment No. 20
Tie-back anchors are not designed for the shoring system, but can be provided if tie-back anchors
are desired.
Comment No. 21
Please clarify the remedial grading (depths and limits of removals, etc.) for proposed at grade
improvements bounding the proposed podium structure.
Response to Comment No. 21
The project should anticipate depths of remedial grading outside the basement structure to a
depth of 5 feet from existing ground surface and extend to the limits of the property. Where
removals abut property lines that may potentially undermine offsite property or improvements,
the remedial grading excavation should be sloped into the project site at an inclination no steeper
than 1:1. During placement of engineered fill, benching and compaction of the bench should
conform to engineered fill recommendations. The height of the bench should be no taller than
one foot plus the depth of the lift of engineered fill layer placed.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 13
Comment No. 22
Please provide setback recommendations for foundations in the proximity of utility trenches or any other
underground improvements from a geotechnical standpoint.
Response to Comment No. 22
Recommendations for foundation setbacks or deepening of the foundation is presented in
GeoTek’s 2022 referenced report under Section 5.3.9 Foundation Setbacks.
Comment No. 23
Please add retaining wall subdrains, temporary excavations, geologic mapping of excavations, retaining
wall backfill, and hardscape subgrade to the list of the geotechnical observations/testing services that
should be provided during the construction of this project.
Response to Comment No. 23
GeoTek concurs with the request and recommends that GeoTek observe retaining wall drains,
temporary excavations, provide geologic mapping of basement excavations during the
construction phase of the project.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 14
CLOSURE
Since GeoTek’s recommendations are based on the site conditions observed and encountered,
and laboratory testing, GeoTek’s conclusions and recommendations are professional opinions
that are limited to the extent of the available data. Observations during construction are
important to allow for any change in recommendations found to be warranted. These opinions
have been derived in accordance with current standards of practice and no warranty is expressed
or implied. Standards of practice are subject to change with time.
Should you have any questions after reviewing this supplementary letter, please feel free to
contact our office at your convenience.
Respectfully submitted,
GeoTek, Inc.
Enclosure:
Figure 1 – Site Location Map (Not Included)
Figure 2 – Updated Geotechnical Map
Figure 3 – Updated Geotechnical Cross Section AA
Figure 4 – Updated Geotechnical Cross Section BB
Appendix A – City of Carlsbad Review Comments dated January 30, 2024,
1st round
Appendix B – GeoTek’s Referenced July 28, 2022 Report
Appendix C – Summary outputs of Global Slope Stability
Appendix D – GeoTek’s Referenced October 23, 2023 Report
Christopher D. Livesey
CEG, 2733 Exp. 05/31/23
Vice President
Edwin R. Cunningham
RCE 81687, Exp. 03/31/26
Project Engineer
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 15
References:
GeoTek, Inc. 2022, “Preliminary Geotechnical Evaluation, Proposed Hope Apartments, Carlsbad,
California,” Project No. 3780-SD, dated July 28, 2022.
, 2023, “Supplemental Geotechnical Recommendations, APN 203-320-20, -02, -48, -51, 40, and -41,
Carlsbad Village Drive and Hope Avenue, Carlsbad, California 92008,” PN 3780-SD, dated
October 23, 2023.
, 2024, “Supplemental Geotechnical Groundwater Design Recommendations, APN 203-320-20, -
02, -48, -51, 40, and -41, Carlsbad Village Drive and Hope Avenue, Carlsbad, California 92008,”
PN 3780-SD, dated April 3, 2024.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008
APPENDIX A
City of Carlsbad Review Comments dated January 30, 2024,
1st round
GEOTEK
GEOTECHNICAL REPORT REVIEW
DATE: January 30, 2024
TO: City of Carlsbad
Land Development Engineering
1635 Faraday
Carlsbad, California, 92008-7314
Attention: David Rick
PROJECT ID: CT2022-0001
GRADING PERMIT NO.: GR2023-0044
SUBJECT: Hope Apartments, Carlsbad Village Drive & Hope Avenue, (1st Review)
Items Submitted by Aoolicant Items Beina Returned to Applicant
• "Preliminary Geotechnical Evaluation, Proposed • Written report revi~w comments.
Hope Apartments, APN's 203-320-20, -02, -48, -
51, -40, and -41, Carlsbad Village Drive and Hope
Avenue, Carlsbad, California,· by GeoTek, dated
May 9, 2022.
Based on our review of the submitted geotechnical report, we are providing the following
comments that should be addressed prior to the next submittal. Please provide complete and
thorough written responses to all comments.
GEOTECHNICAL COMMENTS:
1. The submitted "Preliminary Geotechnical Evaluation ... " by GeoTek, Inc. is approximately
1-1/2 years old, addresses an antiquated code cycle (2019 California Building Code), is
marked "Draft", and is not signed/stamped by the report authors. Consequently, please
review the most current revision of the grading and foundation plans for the proposed
apartment project and provide a complete wet-signed copy of an updated geotechnical
report that is not marked "Draft," is signed/stamped by the report authors, addresses the
current scope of the proposed four-level apartment with subterranean parking structure
development, and addresses the currently adopted 2022 California Building Code.
2. Please provide a statement addressing the potential impact of the proposed project on
adjacent off-site properties from a geotechnical standpoint.
3. Please provide an updated "Geotechnical Map" utilizing the most current revision of the
grading plan for the project as the base map and at a sufficiently large scale to clearly
show (at a minimum): a) existing site topography, b) proposed apartmenUparking structure
GR2023-0044
January 30, 2024
Page 2 of 4
and improvements, c) proposed fin ished grades, d) geologic units, e) locations of
proposed shoring and temporary slopes associated with the subterranean parking level,
and f) the locations of subsurface exploration. Please produce the "Geotechnical Map" at
a scale that is sufficiently large to clearly distinguish all topography, text, finish grades,
elevations, etc., and shows all information requested above (an over-size plate will likely
be necessary to increase legibility and show all requested information).
4. Please provide updated geologic cross-sections A-A' and B-B' based on the updated
"Geotechnical Map " and showing all the information requested in comment #3 above.
Please ensure the cross-sections show, along with the items in comment #3 above, a)
groundwater measured in the subsurface exploration, b) the limits of the recommended
remedial grading, c) the proposed shoring and temporary slopes, and d) the adjacent
streets/improvements (Grand Avenue, Hope Avenue, parking lot and driveway) that bound
the subject site.
5. Please provide a discussion addressing the geologic structure (direction/dip of bedding,
fracturing, etc.) of the Old Paralic deposits and Santiago formation bedrock, and the
relationship between the structural geology of the Old Paralic deposits/Santiago formation
underlying the site as it relates to the retaining wall design for the parking level walls
(geologic surcharge from bedding, etc.), shoring, and stability of the proposed 1: 1 (H:V)
temporary slopes for the proposed construction.
6. Please discuss if the subject site is considered a "Near-Fault Site" in accordance with
ASCE 7-16 and provide updated seismic design parameters for the site as necessary to
address the 2022 California Building Code and ASCE 7-16.
7. Given the geotechnical consultants current understanding of the structure associated with
the proposed four-level apartment with subterranean parking development, please revisit
and discuss the need for site-specific ground motion analysis and provide if necessary.
8. As the expansion index and sulfate exposure testing presented in the report were both
performed on samples of the existing near surface soils (B-5 @ 0-3'), please discuss how
the geotechnical engineering properties of the geologic materials that will be exposed at
the depth of the parking level (approximately 18' to 22' below existing grade) were
assessed with respect to the foundation design and expansion/sulfate conditions. Please
provide testing/recommendations to address and evaluate these conditions as necessary.
9. As several options are presented in the report for foundations for the proposed podium
structure (post-tensioned and conventional foundations), please update (based on review
of the most current plans) and clarify the foundation/slab type that is recommended for the
proposed structure; and provide any updated recommendations as necessary to address
the current development.
10. Please clarify the recommended embedment material (compacted fill, Old Paralic
deposits , Santiago formation) for both the proposed podium structure and at-grade
improvements, as it appears the report currently specifies compacted fill for the proposed
foundations.
11. As foundation/slab recommendations for soils with both "Very Low" and "Low" expansion
potential are provided in the report, please clarify the methods that are being
recommended to address expansive soils for the "Low" case (El greater than 20). As soils
GR2023-0044
January 30, 2024
Page 3 of 4
with Expansion Index (El) over 20 are considered expansive and require mitigation in
accordance with Sections 1803.5.3 and 1808.6 of the 2022 CBC, please provide
recommendations to satisfy the 2022 California Building Code. Please provide the
Effective Plasticity Index and any other parameters for slab-on-ground design in
accordance with 1808.6.2 and WRI/CRSI Design of Slab-on-Ground floors or a post-
tensioned design in accordance with PTI DC 10.5 and provide a statement that the
foundation/slab system for the proposed residential structures will meet the requirements
of Section 1808.6 of the 2022 California Building Code.
12. Please provide updated recommendations for post-tensioned foundation/slab design as
necessary based the most current edition of "Standard Requirements for Design and
Analysis of Shallow of Post-Tensioned Concrete Foundation ... " PTI DC 10.5-19. Please
also provide the basis and supporting data for the parameters for use in the post-tension
slab design (sieve results, percent clay, effective plasticity index, etc.) as necessary.
13. As groundwater levels measured during the subsurface exploration are above the
elevation of the excavation for the parking level of the proposed building and will also be
encountered during the drilling for the shoring piles, please discuss the potential impact of
groundwater on the proposed construction (grading to achieve parking level pad grade,
drilling for shoring piles and installation of lagging, etc.) and provide recommendations to
address as necessary.
14. Please provide recommendation for temporary slopes (maximum allowed height of vertical
cut, maximum inclination of sloping cut, etc.) associated with the proposed relatively deep
excavations for the parking level of the building and other site grading activities.
15. As the current grading plans show approximate 8 to 10' high 1 :1 (H:V) temporary slopes
extending from the top of the proposed shoring and up to within 2' of Grand Avenue and
other off-site property, please provide stability analysis of the 1 :1 slopes exposing fill/Old
Paralic deposits demonstrating the proposed temporary cuts will be safe for workers and
will not adversely impact the city ROW or other offsite property. Please include potential
surcharge loading from emergency vehicle (Fire Truck) in the analysis.
16. Please confirm the 1" deflection of shoring piles discussed in the report will not adversely
impact adjacent offsite property. Please provide the maximum deflection that should be
used for shoring design from a geotechnical standpoint to prevent adverse impacts to
adjacent off-site property.
17. Please provide the minimum diameter for shoring piles and the depth below the parking
level for point of fixity for the shoring piles from a geotechnical standpoint.
18. Please provide active earth pressure for the shoring design for the temporary 1: 1 (H:V)
sloping backfill condition atop the shoring that is currently proposed for the construction of
the subterranean parking levels of the building.
19. The retaining wall recommendations provided in the report appear to address conventional
retaining walls up to a height of 1 O' and not specifically the retaining walls (up to
approximately 22') placed up against shoring that are proposed for the subterranean
parking levels of the building. Please provide updated recommendations for the proposed
retaining wall associated with the subterranean parking level (active/at-rest pressures,
subdrain system, etc.) as necessary.
GR2023-0044
January 30, 2024
Page 4 of 4
,·
20. Please provide recommendations for tieback anchors associated with the shoring system
associated with the parking level of the proposed structure if necessary.
21. Please clarify the remedial grading (depths and limits of removals, etc.) for proposed at-
grade improvements bounding the proposed podium structure.
22. Please provide setback recommendations for foundations in the proximity of utility
trenches or any other underground improvements from a geotechnical standpoint.
23. Please add retaining wall subdrains, temporary excavations, geologic mapping of
excavations, retaining wall backfill, and hardscape subgrade to the list of the geotechnical
observations/testing services that should be provided during the construction of this
project.
l
LEGEND
Approximate Site Boundary
Approximate Limits of Remedial Grading
Approximate Cross-Section
Approximate Location of Exploratory Boring
Approximate Location of Percolation Test
Approximate Geologic Contact
Artificial Fill
Quaternary-age Old Paralic Deposits
Tertiary-age Santiago Formation
B B’
Af
Qop
Tsa
P-2
B-2
1384 Poinsettia Avenue, Suite A
Vista, California 92081
Carlsbad Village II, LLC
Hope Apartments
Carlsbad Village Drive
Carlsbad, CA
PN: 3780-SD April 2024
Figure 2
Geotechnical Map
P-2
P-1
B-4
B-3
B-2
B-1
B-6
B-5
A A’
B’
B
Af
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Af
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P-3
P-4
P-5
?
?
?
?
?
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EMENTS
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-
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DOWNS
/
/
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'~ 7 =_,,66,,.s._,_,nv,_, / ____ _
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~ -n ~ ~ ~ ~~ 2s l~I
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APN: 203-32()..4()
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PER DIVG 15>9 (TYP.) l SE;\£RMA/N
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APN: mJ20.49
____ _)
CARLSBAD VILLAGE DRIVE ~ l.lAN'HO f;
/IE: 60.42)
7 EXISTING f>TOP
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SCALE: 1••JUHORJZONTAL
----
----
I I
- - - -
GEOTEK
1384 Poinsettia Avenue, Suite A
Vista, California 92081
Figure 3
Cross Section A-A’
PN: 3780-SD April 2024
Carlsbad Village II, LLC
Hope Apartments
1009 Carlsbad Village Drive
Carlsbad, CA
1” = 30’
Section A-A’
70
60
50
40
A A’
El
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v
a
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(
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n
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e
a
l
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)
B-1
30
20
Proposed grade for garage
Qop
Af
Tsa
LEGEND
Approximate Boring Location, this report
Approximate Geologic Contact, dashed where buried,
queried where inferred
Existing Grade
Approximate Groundwater Elevation
Property Line
Artificial Fill
Quaternary Old Paralic Deposits
Tertiary Santiago Formation
Qop
Tsa
Af
B-1
PL
Proposed grade Temporary excavation
Intersection of
B-B’
????????
Proposed Basement
Wall
PL/Limits
of remedial
grading
PL/Limits
of remedial
grading
Hope Avenue Proposed
Wall
B-4 B-5
■■■■■■■■
-~c -r -----------r------------~ --.~-~-~-... ,--=------=-=---------,;;----~~--__ \,..,.-' ___ -----i __ ~ =
' -----------------------~--------------------------------;-------------------♦
-.---♦---·/ ✓ -• .......... ~ ................................................................................................................................... .,. ................................................................................... -;.: ....................... .
--
-"""
-"""
--
♦ I ~
I
I
/~
-----------------+------------------+--~ --
-·
--
--
GEOTEK
1384 Poinsettia Avenue, Suite A
Vista, California 92081
Figure 4
Cross Section B-B’
PN: 3780-SD April 2024
Carlsbad Village II, LLC
Hope Apartments
1009 Carlsbad Village Drive
Carlsbad, CA
1” = 30’
70
60
50
40
B B’
Section B-B’
El
e
v
a
t
i
o
n
(
f
e
e
t
a
b
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e
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e
a
n
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e
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l
e
v
e
l
)
PL/Limits
of remedial
grading
PL/Limits
of remedial
grading
B-3 B-1 B-6
30
20
Proposed grade for garage
No significant change between proposed
grade and existing grade
Qop
Af
Tsa
LEGEND
Approximate Boring Location, this report
Approximate Geologic Contact, dashed where buried,
queried where inferred
Existing Grade
Approximate Groundwater Elevation
Property Line
Artificial Fill
Quaternary-age Old Paralic Deposits
Tertiary-age Santiago Formation
Qop
Tsa
Af
B-1
PL
Temporary excavation
Intersection of A-A’
????????
Proposed Basement
Wall
???
???????????
Grand Avenue
--
, f , " ,
,,,--
I --____________ ..,. __ I -------------------------------------------------------------------------~--£ __________________ _ ♦
--• ► --..................................... ' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~ ....................................................... .
---------------------------------------------------------------------------------------~----------------------------
----
----
----
■■■■■■■■
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008
APPENDIX B
GeoTek’s Referenced July 28, 2022 Report
GEOTEK
PRELIMINARY GEOTECHNICAL EVALUATION
PROPOSED HOPE APARTMENTS
APNS 203-320-20, -02, -48. -51, -40, AND -41
CARLSBAD VILLAGE DRIVE AND HOPE AVENUE
CARLSBAD, CALIFORNIA 92008
CT 2022-001/SDP 2022-0006
PREPARED FOR
CARLSBAD VILLAGE II, LLC
3444 CAMINO DEL RIO N, SUITE 202
SAN DIEGO, CALIFORNIA 92108
PREPARED BY
GEOTEK, INC.
1384 POINSETTIA AVENUE, SUITE A
VISTA, CALIFORNIA 92081
PROJECT NO. 3780-SD JULY 28, 2022
GEOTEK
GEOTEK
GEOTECHNICAL | ENVIRONMENTAL | MATERIALS
July 28, 2022
Project No. 3780-SD
Carlsbad Village II, LLC
3444 Camino Del Rio N, Suite 202
San Diego, California 92108
Attention: Mr. Patrick Zabrocki
Subject: Preliminary Geotechnical Evaluation
Proposed Hope Apartments
APN 203-320-20, -02, -48, -51, 40, and -41
Carlsbad Village Drive and Hope Avenue
Carlsbad, California 92008
Dear Mr. Zabrocki:
GeoTek, Inc. (GeoTek) is pleased to provide the results of this Preliminary Geotechnical
Evaluation for the subject project located in the City of Carlsbad, California. This report
presents the results of GeoTek’s evaluation and provides preliminary geotechnical
recommendations for earthwork, foundation design, and construction. Based upon
review, site development appears feasible from a geotechnical viewpoint provided that the
recommendations included herein are incorporated into the design and construction phases
of site development.
The opportunity to be of service is sincerely appreciated. If you should have any questions,
please do not hesitate to call GeoTek.
Respectfully submitted,
GeoTek, Inc.
Christopher D. Livesey Edwin R. Cunningham
CEG 2733 RCE 81687
Associate Vice President Project Engineer
GeoTek, Inc.
1384 Poinsettia Avenue, Suite A Vista, CA 92081-8505
(760) 599-0509 Office (760) 599-0593 Fa www.geotekusa.com
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, California Page i
TABLE OF CONTENTS
1. PURPOSE AND SCOPE OF SERVICES .................................................................................................... 1
2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT .................................................................... 1
2.1 SITE DESCRIPTION .......................................................................................................................... 1
2.2 PROPOSED DEVELOPMENT ............................................................................................................ 2
3. FIELD EXPLORATION AND LABORATORY TESTING ...................................................................... 2
3.1 FIELD EXPLORATION ...................................................................................................................... 2
3.2 PERCOLATION TESTING .................................................................................................................... 3
3.3 LABORATORY TESTING ................................................................................................................... 3
4. GEOLOGIC AND SOILS CONDITIONS ................................................................................................... 3
4.1 REGIONAL SETTING ........................................................................................................................ 3
4.2 EARTH MATERIALS ......................................................................................................................... 4
Artificial Fill (Map Symbol Af) ............................................................................................................ 4
Quaternary-age Old Paralic Deposits (Map Symbol Qop) .................................................................... 4
Tertiary-age Santiago Formation (Map Symbol Tsa) ........................................................................... 4
4.3 SURFACE WATER AND GROUNDWATER ........................................................................................ 5
Surface Water .................................................................................................................................. 5
Groundwater .................................................................................................................................... 5
4.4 EARTHQUAKE HAZARDS ................................................................................................................ 5
Surface Fault Rupture ....................................................................................................................... 5
Liquefaction/Seismic Settlement......................................................................................................... 6
Other Seismic Hazards ..................................................................................................................... 6
5. CONCLUSIONS AND RECOMMENDATIONS ........................................................................................ 6
5.1 GENERAL ........................................................................................................................................ 6
5.2 EARTHWORK CONSIDERATIONS ................................................................................................... 6
General ............................................................................................................................................ 6
Site Clearing and Preparation ............................................................................................................ 7
Remedial Grading ............................................................................................................................. 7
Cut/Fill Transition Lots ...................................................................................................................... 7
Cut Lots ........................................................................................................................................... 8
Engineered Fill .................................................................................................................................. 8
Excavation Characteristics ................................................................................................................. 8
Temporary Basement Excavation ...................................................................................................... 8
Shrinkage and Bulking .................................................................................................................... 10
Trench Excavations and Backfill ................................................................................................. 11
5.3 DESIGN RECOMMENDATIONS ..................................................................................................... 11
Stormwater Infiltration .................................................................................................................... 11
Hydrological Soil Classification ......................................................................................................... 13
Foundation Design Criteria .............................................................................................................. 17
Post Tension Foundation Recommendations ..................................................................................... 18
Conventional Foundation Recommendations..................................................................................... 19
Mat Slab Foundation ...................................................................................................................... 21
Under Slab Moisture Membrane ..................................................................................................... 21
Miscellaneous Foundation Recommendations ................................................................................... 22
Foundation Setbacks ....................................................................................................................... 22
Seismic Design Parameters ........................................................................................................ 23
4.2.l
4.2.1
42.3
4.3,i
43.2
4A-.I
4.4.2
4.4..1
5.1-1
5.2.2
5.2.3
S.2.4
5.1,5
.S.:2.6
5.2]
5.2.8
5.2.9
52.10
5.3.i
5.3~2
5.3.3
5,3.4 .us
5.3.6
5.3.7
5.3.8
5.J.9
5..3.10
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, California Page ii
TABLE OF CONTENTS
Soil Sulfate Content and Corrosivity ............................................................................................ 23
Preliminary Pavement Design ..................................................................................................... 24
Portland Cement Concrete (PCC)................................................................................................ 25
5.4 RETAINING WALL DESIGN AND CONSTRUCTION ........................................................................ 25
General Design Criteria ................................................................................................................... 25
Restrained Retaining Walls ............................................................................................................. 26
Seismic Earth Pressures on Retaining Walls ..................................................................................... 26
Wall Backfill and Drainage ............................................................................................................. 27
6. CONCRETE FLATWORK ......................................................................................................................... 28
6.1 GENERAL CONCRETE FLATWORK ........................................................................................................... 28
Exterior Concrete Slabs and Sidewalks............................................................................................. 28
7. POST CONSTRUCTION CONSIDERATIONS ....................................................................................... 28
7.1 LANDSCAPE MAINTENANCE AND PLANTING .......................................................................................... 28
7.2 DRAINAGE .................................................................................................................................... 29
7.3 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS ................................................................. 29
8. LIMITATIONS ............................................................................................................................................. 30
9. SELECTED REFERENCES ....................................................................................................................... 31
ENCLOSURES
Figure 1 – Site Location Map
Figure 2 – Geotechnical Map
Figure 3 – Geologic Cross Section AA’
Figure 4 – Geologic Cross Section BB’
Appendix A – Logs of Exploration and Percolation/Infiltration Worksheets
Appendix B – Results of Laboratory Testing
Appendix C – General Earthwork Grading Guidelines
5.3. If
5.3.i .2
5.3.13
SA.I
SA2
5.4.J
5.4.4
6.U
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 1
1. PURPOSE AND SCOPE OF SERVICES
The purpose of this study was to evaluate the geotechnical conditions of the project site. Services
provided for this study included the following:
Research and review of available geologic and geotechnical data, and general information
pertinent to the site.
Excavation of six (6) exploratory borings and collection of soil samples for subsequent
laboratory testing.
Excavation of two auger drilled test holes for subsequent percolation testing.
Laboratory testing of the soil samples collected during the field investigation.
Compilation of this geotechnical report which presents GeoTek’s findings of pertinent
site geotechnical conditions and geotechnical recommendations for site development.
2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT
2.1 SITE DESCRIPTION
The subject property is located adjacent to the northeast corner of Carlsbad Village Drive and
(future extension) of Hope Avenue, in the City of Carlsbad, California (see Figure 1). The project
site can be readily identified as 1009 Carlsbad Village Drive, but incudes the broader area of San
Diego Assessor’s Parcel Numbers 203-320-20, -02, -48, -51, 40, and -41. The subject site is
bounded to the north by Grand Avenue, to the east by The Lofts Apartments, to the south by a
restaurant (Carl’s Jr.), and to the west by Hope Avenue. The eastern portion of the site is
occupied by a two-story motel (Carlsbad Village Inn) and a parking lot, the northwest portion of
the site is occupied by one to two-story residential structures, and the southwest is a vacant lot
with what appears to be two slab-on-grade foundations. The grades on the west half and east
half are generally flat, however an approximate four foot tall retaining wall separates the grades
from each side. The west half is at an approximate elevation of 63 feet elevation and the east
half is at an approximate elevation of 69 feet.
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 2
2.2 PROPOSED DEVELOPMENT
Based on the preliminary layout plan provided by Pasco Laret Suiter and Associates, proposed
improvements include a 156-residential unit 4-story structure over a two-level subterranean
podium parking structure. A courtyard, perimeter flatwork, and stormwater BMP planters are
also shown. Associated improvements are anticipated to consist of wet and dry utilities and
offsite public road improvements as well as on-site parking and pavement/hardscaping
improvements.
It is anticipated that the residential buildings will be of wood frame construction and the
subterranean podium-style parking structure is anticipated to be constructed of reinforced
concrete. For the purposes of this report, it is assumed preliminary design dead loads for the
garage columns are 360 kips with a live load of 110 kips. Once actual loads are known that
information should be provided to GeoTek to determine if modifications to the
recommendations presented in this report are warranted.
As site planning progresses and additional or revised plans become available, they should be
provided to GeoTek for review and comment. If plans vary significantly, additional geotechnical
field exploration, laboratory testing and engineering analyses may be necessary to provide specific
earthwork recommendations and geotechnical design parameters for actual site development
plans.
3. FIELD EXPLORATION AND LABORATORY TESTING
3.1 FIELD EXPLORATION
GeoTek’s field study, conducted on April 6th and 7th 2022, consisted of a site reconnaissance and
excavation of six (6) exploratory borings advanced with a conventional CME-75 hollow-stem
auger drilling rig mounted on a rubber tired truck. Boring depths ranged from between 16 and
50 feet below existing grade. Excavation of two (2) additional borings, P-1 and P-2, to depths of
approximately 5 feet below grade, were performed for percolation testing. A representative
from GeoTek visually logged the borings in accordance with the Unified Soil Classification System
(USCS), collected relatively undisturbed and loose bulk soil samples for laboratory analysis, and
transported the samples to GeoTek’s laboratory. Percolation tests were performed the following
day. Approximate locations of the exploratory borings and percolation test holes are presented
on the Geotechnical Map, Figure 2. A description of material encountered in the test borings is
included in Appendix A.
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 3
3.2 PERCOLATION TESTING
Two percolation borings (Borings P-1 and P-2) were excavated to depths approximately 4 to 4.5
feet below the existing ground surface. The boring bottom and side walls were scarified and
cleaned as feasible of potential drilling fines adhered to the boring walls. The test hole was then
filled with potable water to pre-soak. Following overnight pre-soaking, the test holes were filled
with water and the drop in water level was recorded every 30 minutes. The test was continued
for a minimum of twelve readings and the final reading was used in the calculation of the
infiltration rate. The field data was converted to an infiltration rate via the Porchet method. Over
the lifetime of the storm water disposal areas, the infiltration rates may be affected by silt build
up and biological activities, as well as local variations in near surface soil conditions. The rates
presented below do not include a factor of safety, the BMP designer should include appropriate
factors of safety in their design.
INFILTRATION TEST RESULTS
Test No. Approximate Boring Depth
(Inches)
Infiltration Rate
(Inches per hour)
P-1 48 0.54
P-2 54 0.55
Copies of the percolation data sheets and infiltration conversion sheets (Porchet Method) are
included in Appendix A.
3.3 LABORATORY TESTING
Laboratory testing was performed on bulk soil samples collected during the field explorations.
The purpose of the laboratory testing was to evaluate their physical and chemical properties for
use in engineering design and analysis. Results of the laboratory testing program, along with a
brief description and relevant information regarding testing procedures, are included in
Appendix B.
4. GEOLOGIC AND SOILS CONDITIONS
4.1 REGIONAL SETTING
The subject property is located in the Peninsular Ranges geomorphic province. The Peninsular
Ranges province is one of the largest geomorphic units in western North America. It extends
roughly 975 miles from the north and northeasterly adjacent the Transverse Ranges geomorphic
province to the peninsula of Baja California. This province varies in width from about 30 to 100
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 4
miles. It is bounded on the west by the Pacific Ocean, on the south by the Gulf of California and
on the east by the Colorado Desert Province.
The Peninsular Ranges are essentially a series of northwest-southeast oriented fault blocks.
Several major fault zones are found in this province. The Elsinore Fault zone and the San Jacinto
Fault zones trend northwest-southeast and are found in the near the middle of the province. The
San Andreas Fault zone borders the northeasterly margin of the province. The Newport-
Inglewood-Rose Canyon Fault zone meanders the southwest margin of the province. No faults
are shown in the immediate site vicinity on the map reviewed for the area.
4.2 EARTH MATERIALS
A brief description of the earth materials encountered during the current subsurface exploration
is presented in the following sections. Based on the field observations and review of published
geologic maps the subject site is locally underlain by artificial fill (Af) over Quaternary-age Paralic
Deposits (Qop) over Tertiary-age Santiago Formation (Tsa).
Artificial Fill (Map Symbol Af)
Artificial fill was encountered in all borings between one and six feet below existing grades. The
fill soils along the west half were as shallow as one to two feet and consisted of reddish to light
brown silty sand (SM soil type based upon the Unified Soil Classification System) that may have
been disturbed due to demolition and construction. The fills in the eastern half were as deep as
six feet and consisted of silty medium to coarse sand (SP soil type) consistent with decomposed
granite fill.
Quaternary-age Old Paralic Deposits (Map Symbol Qop)
Old Paralic Deposits were encountered in test borings B-1, B-3 and B-6 at approximate depths
between two and twenty feet below the ground. The formational material consisted of medium
dense to dense, reddish brown, moist to wet, silty fine to medium sand (SM soil type).
Tertiary-age Santiago Formation (Map Symbol Tsa)
Santiago Formation was encountered in all borings with exception to B-2 which was terminated
due to utility conflicts. Santiago Formation was encountered at depths between six and total
depths explored (50 feet) and consisted of very dense, light gray, wet, silty fine sandstone
(excavates as SM soil type). It should be noted that a significant depth to Santiago Formation was
observed between the western and eastern half of the site. The western half encountered
Santiago Formation at depths of 20 feet, whereas the eastern half encountered Santiago
Formation at near the surface to a depth of 6 feet. The stratigraphical difference between the
Santiago Formation between the western and eastern halves of the site are attributed to
transgressional depositional episode against a paleo bluff (ancient shoreline and bluff). This
4.2.1
4.2.2
4.2.3
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 5
interpretation is consistent with the historic geology and depositional environment of the geology
setting of the Old Paralic Deposits.
4.3 SURFACE WATER AND GROUNDWATER
Surface Water
Surface water was not observed during the recent site exploration. If encountered during
earthwork construction, surface water on this site will most likely be the result of precipitation.
Provisions for surface drainage will need to be accounted for by the project civil engineer.
Groundwater
Groundwater was encountered during exploration of the subject site. Based on the anticipated
depth of excavation, groundwater is anticipated to be a factor in site design, development and
post construction. The following table presents tabulated groundwater data. Data has been
obtained by direct measurement during field exploration and research review of the adjacent
property (The Lofts), and readily available data.
Summary of Groundwater Data
Reference ID Date Surface
Elevation (ft)
Depth
(ft)
Elevation
(ft)
Boring B-1 4/6/22 63 10 53
Boring B-3 4/6/22 69 10 59
Boring B-4 4/6/22 69 19 50
Boring B-5 4/6/22 69 5 64
Boring B-6 4/6/22 63 11 52
The Lofts
(1044 Carlsbad Village Drive)
---- ~74 10.5 ~63.5
4.4 EARTHQUAKE HAZARDS
Surface Fault Rupture
The geologic structure of the entire southern California area is dominated mainly by northwest-
trending faults associated with the San Andreas system. The site is not in a seismically active
region. No active or potentially active fault is known to exist at this site nor is the site situated
within an “Alquist-Priolo” Earthquake Fault Zone or a Special Studies Zone (Bryant and Hart, 2007).
No faults transecting the site were identified on the readily available geologic maps reviewed.
The nearest known active fault is the Newport Inglewood-Rose Canyon fault located about five
miles to the southwest of the site.
4.3.1
4.3.2
4.4.1
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Liquefaction/Seismic Settlement
Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake-induced
ground motion, create excess pore pressures in relatively cohesionless soils. These soils may
thereby acquire a high degree of mobility, which can lead to lateral movement, sliding,
consolidation and settlement of loose sediments, sand boils and other damaging deformations.
This phenomenon occurs only below the water table, but, after liquefaction has developed, the
effects can propagate upward into overlying non-saturated soil as excess pore water dissipates.
The factors known to influence liquefaction potential include soil type and grain-size, relative
density, groundwater level, confining pressures, and both intensity and duration of ground
shaking. In general, materials that are susceptible to liquefaction are loose, saturated granular
soils having low fines content under low confining pressures.
The liquefaction potential and seismic settlement potential on this site is considered negligible
due to the density of the underlying Santiago Formation materials and consideration of proposed
design (subterranean podium-style parking structure).
Other Seismic Hazards
The potential for landslides and rockfall is considered negligible, due to the low gradient
topographic setting of the site. The potential for secondary seismic hazards such as seiche and
tsunami is remote due a review of California Department of Conservation, Geologic Survey,
Tsunami Inundation San Luis Rey Quadrangle, 2009.
5. CONCLUSIONS AND RECOMMENDATIONS
5.1 GENERAL
Development of the site appears feasible from a geotechnical viewpoint provided that the
following recommendations are incorporated in the design and construction phases of the
development. The following sections present general recommendations for currently anticipated
site development plans.
5.2 EARTHWORK CONSIDERATIONS
General
Earthwork and grading should be performed in accordance with the applicable grading ordinances
of the City of Carlsbad, the 2019 (or current) California Building Code (CBC), and
4.4.2
4.4.3
5.2.1
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Proposed Hope Apartments, Carlsbad, California Page 7
recommendations contained in this report. The Grading Guidelines included in Appendix C
outline general procedures and do not anticipate all site-specific situations. In the event of
conflict, the recommendations presented in the text of this report should supersede those
contained in Appendix C.
Site Clearing and Preparation
Site preparation should start with removal of deleterious materials, vegetations, and trees/shrubs
in the proposed improvement areas. These materials should be disposed of properly off site. Any
existing underground improvements, utilities and trench backfill should also be removed or be
further evaluated as part of site development operations.
Remedial Grading
Prior to placement of fill materials and in all structural areas, the upper variable, potentially
compressible materials should be removed. Removals should include at a minimum all fills. Based
on the explored locations, an average removal depth of 3 feet from existing grades may be
anticipated. However, considering the proposed subterranean podium style parking structure
design, excavation for the parking structure is anticipated to remove all unsuitable soils.
The bottom of the removals should be observed by a GeoTek representative prior to processing
the bottom for receiving placement of compacted fills. Depending on actual field conditions
encountered during grading, locally deeper and/or shallower areas of removal may be necessary.
Prior to fill placement, if fills are needed to reach design grades, the bottom of all removals should
be scarified to a minimum depth of six (6) inches, moisture conditioned to slightly above optimum
moisture content, and then compacted to at least 90% of the soil’s maximum dry density as
determined by ASTM D1557 test procedures. The resultant voids from remedial grading/over-
excavation should be filled with materials placed in general accordance with Section 5.2.6
Engineered Fill of this report.
Cut/Fill Transition Lots
Grading may result in a cut/fill transition at the proposed building pad finish grades. If a geologic
contact of Formational material against fills is encountered at finish pad grades, the cut portion
should be over-excavated a minimum of five feet below pad grades, or two feet below the base
of proposed footings, whichever is deeper, and be replaced with engineered fill. Cut/fill
transitions may occur across ancillary or detached buildings outside of the subterranean parking
structure footprint. Depending on the proposed design, an alternative to overexcavating across
the entire site, where small fills are needed, could be to compact the fill material to 95 percent
compaction relative to ASTM D1557. GeoTek should be contacted for additional considerations
on such a case.
5.2.2
S.2.3
5.2.4
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Cut Lots
Lots wholly excavated in a cut condition exposing sandstone of the Santiago Formation may
remain as cut. This will be the case for the subterranean (basement) parking structure.
Engineered Fill
Onsite materials are generally considered suitable for reuse as engineered fill provided, they are
free from vegetation, roots, debris, and rock/concrete or hard lumps greater than six (6) inches
in maximum dimension. The earthwork contractor should have the proposed excavated
materials to be used as engineered fill at this project approved by the soils engineer prior to
placement.
Engineered fill materials should be moisture conditioned to at or above optimum moisture
content and compacted in horizontal lifts not exceeding 8 inch in loose thickness to a minimum
relative compaction of 90% as determined by ASTM D1557 test procedures.
Excavation Characteristics
Excavations in the onsite materials can generally be accomplished with heavy-duty earthmoving
or excavating equipment in good operating condition. Exploratory borings were advanced with
relative ease, however when driving the samples, blow counts indicated dense and very dense
silty sandstones. A rippability survey was not performed as part of the scope of work under this
report. If desired, a rippability survey can be provided. This report should be reviewed by the
grading contractors solicited for grading construction, as hallow stem auger boring and excavation
with track hoe equipment is not equivalent. Advancement of a boring may be more readily
performed compared to a bucket excavator.
Temporary Basement Excavation
Depending on the actual design of the basement footprint, excavation of the basement may be
feasible by sloping the excavations. Based on preliminary discussions with the client, a soldier
beam and wood lagging with tie-back anchors are preferred for the basement excavation.
It is extremely difficult to predict accurately the amount of deflection of a shored excavation. It
should be realized that some deflection will occur. It is estimated that this deflection may be on
the order of 1-inch at the top of the shored excavation. If greater than expected deflection
occurs during construction, additional bracing may be necessary to minimize adjacent area
settlement. If it is desired to reduce the deflection of the shoring, a greater lateral earth pressure
(such as at-rest earth pressures) may be used in the shoring design with an increased stiffness of
the system.
Soldier pile installations consisting of a concrete encased steel H-beams should be observed by
the project geotechnical consultant to verify excavations are drilled into anticipated conditions,
5.2.5
5.2.6
5.2.7
5.2.8
GEOTEK
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pile excavations are properly prepared and cleaned out, dimensions are achieved, and specific
installation procedures are followed. The shoring to be constructed at the site should be
surveyed and monitored on a regular basis for any movement. If any significant movement is
observed during shoring and construction operations, it should be brought to the immediate
attention of the project general contractor, shoring contractor and geotechnical consultant for
appropriate corrective measures.
It is recommended that during design of the shoring GeoTek be contacted for review of
geotechnical design parameters.
Soldier Piles
Soldier piles installed to support earth pressures are anticipated to be concrete encased H piles,
designed by the project structural engineer or shoring engineer. Other reasonable shoring
options might be sheet piling and/or secant or tangent drilled piers.
The excavation for the proposed basement is anticipated to expose bedrock materials of the
Santiago Formation. Santiago Formation bedrock is also expected to be encountered at the base
of some of the excavations. As old paralic deposits and artificial fill overly the bedrock in this
portion of the project site, measures to prevent caving should be considered during excavation.
The drilling contractor should be made aware of the presence of bedrock and that appropriate
heavy-duty drilling equipment in good working order and/or special drilling techniques will be
required. It should be realized that the ability of any particular contractor to excavate the
materials encountered will vary based on factors that may or may not be considered in the
presented evaluation. All methods available to evaluate rock hardness and associated rippability
are interpretive to some extent. As such, experience and judgment are primary factors in such
evaluations.
For design of cantilevered shoring, lateral at-rest or active earth pressures may be suitable with
a static lateral pressure equal to that developed by a fluid with a density of 40 pounds per cubic
foot (pcf) for the active condition and 65 pcf for the at-rest condition for retained material with
level backfill. The actual pressure distribution to be used for design should be determined by the
structural/shoring engineer. For braced excavations, the shoring could be designed based on a
uniform pressure distribution with a pressure value of 22.0 H psf, where H is the wall height in
feet.
The above equivalent fluid weights do not include other superimposed loading conditions such
as vehicular traffic, hydrostatic (water table), structures, construction materials, seismic
conditions, etc. Applicable surcharge loads should be considered and applied by the
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structural/shoring engineer. The project structural/shoring engineer should design the shoring
system using a suitable factor of safety and it should be designed for the lowest adjacent grade.
For the design of soldier piles, an ultimate lateral bearing value (passive value) of 300 pounds per
square foot per foot of depth, to a maximum value of 4,500 psf, may be assumed for material
below the level of excavation to determine soldier pile depth and spacing. The effective width
of the soldier pile can be assumed to be twice the solder pile diameter for passive pressure
calculations. However, passive resistance should be ignored within the upper foot due to
possible disturbance. To develop the full lateral value, provisions should be taken to assure firm
contact between the soldier piles and the undisturbed earth material. The construction of the
shoring system should be monitored continuously, and adjacent structures/improvements should
be observed for any potential lateral and vertical movement.
Lagging
Design of lagging is the purview of the shoring designer. Lagging should be installed at a maximum
5-foot vertical unsupported cut as the excavation is advanced. Field conditions including earth
material classification and seepage during construction may determine if this height of vertical
cut needs to be reduced to less than 5 feet. Friable soils were noted in the boring logs and
indicates caving or sluffing soil may be encountered during excavation of lagging. The upper one
foot of the lagging should be grouted or slurry–filled to assist in diverting surface water from
migrating behind the shoring walls.
The lagging should be backfilled immediately as the excavation is advanced in order to minimize
the voids created between the lagging and vertical cut and also to reduce the potential for ground
subsidence behind the wall. The lagging material should be designed considering it may serve as
a permanent installation.
Shrinkage and Bulking
Several factors will impact earthwork balancing on the site, including undocumented fill shrinkage,
trench spoil from utilities and footing excavations, as well as the accuracy of topography.
Shrinkage is not anticipated to be a factor in quantities estimating, as the site, based on the
proposed basement construction will likely be an export site. For excavations in the formational
material (Old Paralics and Santiago Formation) silty sandstone, a bulking factor of 10 percent may
be considered. Subsidence should not be a factor on the subject site due to the presence of near
surface formational material.
5.2.9
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Trench Excavations and Backfill
Temporary excavations within the onsite materials should be stable at 1:1 inclinations for short
durations during construction, and where cuts do not exceed 10 feet in height. Temporary cuts
to a maximum height of 4 feet can be excavated vertically.
Trench excavations should conform to Cal-OSHA regulations. The contractor should have a
competent person, per OSHA requirements, on site during construction to observe conditions
and to make the appropriate recommendations.
Utility trench backfill should be compacted to at least 90% relative compaction of the maximum
dry density as determined by ASTM D1557 test procedures. Under-slab trenches should also be
compacted to project specifications.
Onsite materials may not be suitable for use as bedding material but should be suitable as backfill
provided particles larger than 6± inches are removed.
Compaction should be achieved with a mechanical compaction device. Ponding or jetting of
trench backfill is not recommended. If backfill soils have dried out, they should be thoroughly
moisture conditioned prior to placement in trenches.
5.3 DESIGN RECOMMENDATIONS
Stormwater Infiltration
Many factors control infiltration of surface waters into the subsurface, such as consistency of
native soils and bedrock, geologic structure, fill consistency, material density differences, and
existing groundwater conditions. Current site plans indicate several modular basins located on
the east and west perimeter of the property, which are shown on Figure 2.
A review of the site conditions and proposed development was performed in general accordance
with the City of Carlsbad BMP design manual. The scope of stormwater evaluation was
performed to identify infiltration characteristics. As required by the City of Carlsbad BMP design
manual, the following bullet points describe required considerations and some optional
considerations. The BMPs were evaluated each based on required considerations and all were
found to be limiting infiltration by the same restrictive consideration, therefore, to present a
simple discussion the following discussion regards all BMPs, unless where specifically discussed.
5.3.1a. Based on a review of www.geotracker.com, environmental impacted sites are not
reported within 100 feet of the site.
5.2.10
5.3.1
GEOTEK
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5.3.1b. Based on a review of Geotracker.com and a reconnaissance of the properties
surrounding the site, which were found to be residential, there was not an industrial
active building that may pose a lack of source control within 100 feet of the site.
5.3.1c. Based on the surrounding existing development and the understanding that the
proposed project will be supported by a municipal sanitation system, the BMPs are
not located within 50 feet of septic tanks or leach fields.
5.3.1d. Based on a review of the proposed improvements, the BMPs are not designed within
10 feet of structural retaining walls (basement).
5.3.1e. Based on a review of the proposed improvements, the BMPs are anticipated to be
designed within 10 feet of sewer utilities.
5.3.1f. Based on a review of the geologic information for the site and the site specific
evaluation that identified shallow dense bedrock within two feet of the surface.
Infiltration of surface waters will develop a shallow perched groundwater condition
within 10 feet of the BMPs.
5.3.1g. Based on a review of the topography of the site, hydric soils are not prone to exist.
However, based on the shallow bedrock of the site and in low gradient proposed
areas, hydric soils have the potential to develop due to infiltration of surface waters.
5.3.1h. Based on the shallow bedrock, hazards due to liquefiable soils is considered to be
low.
5.3.1i. Based on the proposed design, the BMPs are not located within 1.5 times the height
of an adjacent steep slope (basement).
5.3.1j. Based on the site specific study and conclusion, the site is within a predominantly
type D soil.
Based on outline numbers 5.3.1d, e, f, and g, the DMA’s for the site are classified as restricted
for infiltration. As the DMAs are considered to be restricted design infiltration rates are not
considered necessary.
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Based on the restricted category of the DMA, the proposed basin should be designed for filtration
and all sides, including the bottom, should be designed with an impermeable liner to mitigate the
potential for groundwater mounding to develop and/or migrate laterally and impact the proposed
design improvements.
Hydrological Soil Classification
Summary of Mapped Soil Conditions
The United States Department of Agriculture, Natural Resource Conservation Service, Web Soil
Survey (WSS), an internet based map service, classifies the majority of the site (approximately
85% based on area) as MIC Marina loamy coarse sand, 2-9% slopes. The interpretative unit (MIC)
is classified as a hydrological Group B.
Table D.1-1: Considerations fo r Geotechnical Analysis of Infiltration Restrictions
Mandatory
Considerations
Optional
Considerations
Result
Restriction Element
BMP is within 100' of Contaminated Soils
BMP is within 100' of Industrial Activities Lacking Source Control
BMP is within 100' of Well/Groundwater Basin
BMP is within 50' of Septic Tanks/Leach Fields
BMP is within 10' of Structures/Tanks/Walls
BMP is within 10' of Sewer Utilities
BMP is within 10' of Groundwater Table
BMP is within Hydric Soils
BMP is within Highly Liquefiable Soils and has Connectivity to Structures
BMP is within 1.5 Times the Height of Adjacent Steep Slopes (~25%)
County Staff has Assigned "Restricted" Infiltration Category
BMP is within Predominantly Type D Soil
BMP is within 1 O' of Property Line
BMP is within Fill Depths of ~5' (Existing or Proposed)
BMP is within 10' of Underground Utilities
BMP is within 250' of Ephemeral Stream
Other (Provide detailed geotechnical support)
Based on examination of the best available information,
Is Element
Applicable?
(Yes/No)
No
No
No
No
Yes
Yes
No
No
No
No
Yes
Yes
Yes
No
□
I have not identified any restrictions above. Unrestricted
Based on examination of the best available information, IXI
I have identified one or more restrictions above. Restricted
Table D .1-1 is divided into Mandatory Considerations and Optional Considerations. Mandatory
5.3.2
GEOTEK
Existing fills
and new fills of
5 to 6 feet are
In the eastern
half of the site
and associated
BMPs
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
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Proposed Hope Apartments, Carlsbad, California Page 14
The WSS classifies map units based on topography, weather, typical soil section in the upper 40
inches, hydrological properties (slope gradient, drainage class, infiltration rates, runoff potential,
flood potential) and interpretative groups (land capability classification, hydrologic soil group,
hydric soil rating).
The WSS uses the National Soil Survey Handbook (NSSH) and its eDirectives to provide national
continuity of soil classifications related to the agricultural industry. Classification is based on
laboratory testing of field samples, direct testing in the field, and interpretations from aerial and
satellite photography. Samplings and laboratory analyses are performed on select sites and
extrapolated beyond the sampled locations.
The NSSH states that “increased mapping has been performed by remote spatial interpretations
in lieu of updating surveys based on new or supplemental laboratory data.”
The WSS provides the location of data points on their interpretive maps. Data sets are
predominately concentrated in agricultural areas and are sparsely available in urban and suburban
areas (if at all). A review of the WSS data set was performed. The closest data sample identified
is located at the approximate location of El Mirlo Drive, Oceanside, California. That data point
is approximately 8 miles northeast of the subject site, in a different geologic unit (Kt-
Tonalite/granitics) and presumably obtained prior to the existing development of the residential
tract homes at the stated location. The survey methodology on the WSS for the site is noted to
be based on aerial photography dated September 13, 2021.
The WSS has classified the site improvement area as a hydrological Group B. It should be noted
that the soil classification in the WSS are based on taxonomy principally for agricultural purposes.
Classification of soils presented on the logs utilize the Unified Soil Classification Standard, as per
industry standards. GeoTek’s findings result in inconsistencies between the site and information
provided on the WSS. These inconsistencies include:
The WSS classifies the site as a hydrological Group B, which is defined by eDirective 630, Chapter
7 as:
Group B—Soils in this group have moderately low runoff potential when thoroughly wet.
Group B soils typically have less than 10 to 20 percent clay and 50 to 90 percent sand.
The limits on the diagnostic physical characteristics of group B are as follows…..Soils that
are deeper than 40 inches to a water impermeable layer and a water table are in group B
if the saturated hydraulic conductivity of all soil layers within 40 inches of the surface is
between 0.57 and 1.42 inches per hour.
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Based on GeoTek’s site specific study, the site has formational material Bedrock between 20 to
40 inches below the ground.
Following the flow chart of Table 7-1: depth to high groundwater is anticipated to be
great than 40 inches. Ksat depth rancge is between 0 and 40 inches, limited by near
surface bedrock (formational material). As a result, the site is classified as a Group D.
The WSS National Engineering Handbook provides a table summarizing the criteria for
assignment of hydrological soil groups in Table 7-1. This table has been presented herein and
highlights the criteria that identifies the site, specific to our findings (noted in yellow high lighter):
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Table 7-1 (NEH, 2009)
l)eptlt to Ater Depthooldgh. X...t of leM trllllsmhslve Jt..i4eptb BSGJI'
limpe.nneable layer II water table~ layer hi depth u.nge n~
I <60 m D 1<20 inl ---
>4.0.0 pm/s
I
Oto80 cm ND (;:,5.67 inlh) [O t.o241n]
> 10.Q ta s40,0 JlDJ/s Oto 0 cm BID <:6CI cm (> 1.42 to :s'>.67 irl/h) I [Oto 24 In]
[<24 in] :,. LO to ~! 0.0 µrm.ls to£-O . m CID (;::,-0.14 to ~l.42 illlh) [Oto 24 in]
:S.1.0 µm/s to60 cm D 50to HIO cm (:50.14 ln/h) [Oto 24, in]
[20to40in] :;,4(1,0 Jun/8, 0to60cm A (>5.67 i.ru'h) [Oto20 in]
>IO.Oto .0 Jml/s
I
Oto 5{) cm B ;;:oocm (>l.42 to Sh.67 in/h) [Oto 20 in]
[~in] > 1.0 to :iao.o Inn/s Oto 60 cm C (><l.14 to ~1.42 inlh) [Oto 20 in]
:::;;I.Opm/s
I
0 to 5-0 cm D (~0.14 in/h) [O to20in]
>10.0 .µmis. 0 to 100 cm AID (>1.42 i:n/h) [Oto40 in]
>•1.0 to Sl0.0 prm,fs
I
o to rno em BID ,-::OOc:m ( >0.57 to ~l.42 :iwh) [Oto 40 in]
[<24 In] >OAO to g_o i1tmls Cl lo 100 cm CID (>0.06,to :S0.57 inlh) [Oto 40 in.I
~.40µrn/s
I
Cl to 100 em D >100cm (~:06 in/h} [Oto 40 in]
[>40 inJ ~40.0 Jl[IVS Oto50cm A (>5.67 i.n/h) roto20in]
>10.0 :«-0:0 Im,/ OtooOcm B OOto 100cm (>1.42 to §.67 inlh) [Oto 20in]
124to40In] > l .0 t.o ~10.0 pm.ls Oto60 c:m
(;;,0.14 to 51.42 inlh) [Oto 20 In]
:S.l.Oµrn/s I 0 to Ml cm D (:50.14 ln/h.) [Oto 20 in]
>l0.0J1mls
I
Oto 100 cm A (:>1.42 '.i:n/h) [Oto 4,0 in]
>4.0 to S 10.0 µmis Oto UIO m B :;,IOOcm (>-0.57 to :Sl.42 inlh) [Oto 40 in]
[>40 in] >0.40to -.o µmis Oto 100 cm
I (>(};06 to 5.0.57 inlh) [Oto 40 in)
<fl 401mu'io ,() t;.-. 1110 "!rtl D 1._::,,u .UO III/AJ lll to40mJ "f
' . U An un mtt'.abl Loy r l\:l.'i K,;,.t les5 than 0.01 p1nf.s ,[0.0014 inlb] or m n III restn n r fi-agt,pan;
duripan; peu ruci o:rstein:; petro&YP'Sic: oemented hociron; densic mate.rial: p!aci~ bed k, llhk;
brorock, Ulhl ; brorock, d I c-: or pennaf
2/ IDgh water table durlrtg any montl'I during the year.
3/ Dual lfSG clas.~ lilre appUe<l only fo w t soils (water table less than 00 ('ffl 124 in]). lfthese soils ,c3n be
dralriod, a ll!SS reslrictlcv-e I-JSG can bQ' asslgnic-d, df!pendlng Oll lhe K..it•
GEOTEK
I
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 17
Foundation Design Criteria
Preliminary foundation design criteria, in general conformance with the 2019 CBC, are presented
herein. Based on conversations with you, conventional, post-tension, mat slap and tie-downs are
being considered. These are typical design criteria and are not intended to supersede the design
by the structural engineer. Updated or revised foundations may be needed based on updated
design and can be provided upon request. Independent of foundation selection the following
recommendations should be considered.
Groundwater will need to be addressed due to the subterranean parking garage design
elevations. A temporary dewatering system will be anticipated to be needed to handle
the influx of groundwater anticipated. A permanent system may also be considered.
The structural engineer should take into account the bouncy force when designing for the
subterranean basement if a permanent system is not designed.
Waterproofing of the retaining walls and subterranean foundation should be addressed
by the architect and/or structural engineer.
Based on visual classification of materials encountered onsite and plasticity index of the soils as
verified by laboratory testing, site soils are anticipated to exhibit a “very low” (EI < 20) expansion
index and “low” (21<EI<50) expansion index design parameters are provided for conservancy.
Additional laboratory testing should be performed at the time of supplemental geotechnical
evaluations and upon completion of site grading to verify the expansion potential and plasticity
index of the subgrade soils. If not, the more conservative foundation design category should be
utilized (low expansive condition).
An allowable bearing capacity of 4,500 pounds per square foot (psf) may be used for
design of continuous and perimeter footings that meet the depth and width
requirements in the table above. This value may be increased by 300 pounds per
square foot for each additional 12 inches in depth and 200 pounds per square foot for
each additional 12 inches in width to a maximum value of 6,500 psf. Additionally, an
increase of one-third may be applied when considering short-term live loads (e.g.,
seismic and wind loads).
Based on experience in the area, structural foundations may be designed in accordance
with the 2019 CBC to withstand a total settlement of 1-inch and maximum differential
settlement of one-half of the total settlement over a horizontal distance of 40 feet.
The passive earth pressure may be computed as an equivalent fluid having a density of
300 psf per foot of depth, to a maximum earth pressure of 4,500 psf for footings
5.3.3
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 18
founded on engineered fill. A coefficient of friction between soil and concrete of 0.33
may be used with dead load forces. passive pressure and frictional resistance can be
combined without reduction.
A grade beam should be utilized across large entrances. The depth and the width of
the grade beam should be the same as the adjoining footings.
Post Tension Foundation Recommendations
Presented below are post-tensioned (PT) foundation design parameters for the proposed
structures at the site. Following site grading, it is anticipated that the upper building pad soils
will have a “very low” and “low” expansion index potential. These parameters are in general
conformance with Design of Post-Tensioned Slabs-on-Ground, Third Edition with 2008 Supplement
(PTI, 2008). These recommendations are minimal recommendations and are not intended to
supersede the design by the project structural engineer.
PT Design for Very Low Expansive Soils
Based upon the Post Tensioning Institute (PTI) “Design of Post-Tensioned Slabs-on-Ground (3rd
edition), soils having a “very low” (0-20) expansion potential can be considered “non-active”.
Since the 2019 California Building Code (CBC) indicates Post Tensioning Institute (PTI) design
methodology is intended for expansive soils conditions, which do not apply to soils having a “very
low” (0-20) expansion potential, no em or ym parameters as used in the PTI methodology are
provided for soils having a “very low” (0-20) expansion potential.
For “non-active” soils (soils having a “very low” expansion potential), foundation
recommendations can be consistent with a Building Research Advisory Board (BRAB) Type II
foundation system, which is “lightly reinforced against shrinkage and temperature cracking”. This
type of foundation system can be reinforced with either steel reinforcement bars or post-
tensioned cables. Post-tensioning for this type of foundation system should utilize the
recommended design procedure by the referenced PTI manual and 2019 CBC. All reinforcing
(steel or post-tensioning) should be properly designed and specified by the structural engineer.
PT Design for Very Low Expansive Soils
Post-tensioned slab foundation design parameters for structures constructed on soils having a
“low” expansion index potential for this project are as follows:
5.3.4
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 19
GEOTECHNICAL RECOMMENDATIONS FOR
POST-TENSIONED SLABS
Foundation Design Parameter
“Low”
Expansion Potential (EI≤50)
LL≤38; PI≤15; Material Passing #200
Sieve = 40%;
Clay Fines = 10%
Edge Moisture Variation Distance, em
- Edge Lift (swelling)
- Center Lift (shrinkage)
4.8 ft
9.0 ft
Soil Differential Movement, ym
- Edge Lift (swelling)
- Center Lift (shrinkage)
≈0.67 in
≈0.29 in
Exterior Perimeter Beam Embedment 12 inches*
Presaturation of Subgrade Soil (Percent of Optimum) Minimum 100% to a depth of
12 inches
*Required depth of perimeter beam/stiffening rib per structural calculations may govern.
The following assumptions were used to generate em and ym values: Thornthwaite Moisture Index = -
20; constant suction value = 3.9pF; post-equilibrium case assumed with wet (swelling) cycle going from
3.9pF to 3.0pF and drying (shrinking) cycle going from 3.9pF to 4.5pF.
Post-tensioned slabs should be designed in accordance with the 2019 CBC and PTI design
methodology.
The bottom of the perimeter edge beam/deepened footing should be designed to resist tension
forces using either cable or conventional reinforcement, per the structural engineer.
It should be noted that the above recommendations are based on soil support characteristics
only. The structural engineer should design the slab and beam reinforcement based on actual
loading conditions.
Conventional Foundation Recommendations
Foundation design criteria for a conventional foundation system, in general conformance with the
2019 CBC, are presented below. Following site grading, the site soils are anticipated as having a
“very low” (EI<20) and “low” (21<EI<50) expansion index in accordance with ASTM D 4829.
These are minimal recommendations and are not intended to supersede the design by the project
structural engineer.
5.3.5
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 20
The conventional foundation elements for the proposed structures should bear entirely in
engineered fill soils. Foundations should be designed in accordance with the 2019 or current
applicable version of the CBC.
A summary of GeoTek’s preliminary foundation design recommendations is presented in the
table below:
Design Parameter
Category I
“Very Low” Expansion
Index
Category II
“Low” Expansion Index
Foundation Depth or
Minimum Perimeter Beam
Depth
(below lowest adjacent grade)
1-story = 12 Inches
2-story = 18 Inches
3-story = 24 Inches
4-story = 30 Inches
1-story = 18 Inches
2-story = 18 Inches
3-story = 24 Inches
4-story = 30 Inches
Perimeter or Continuous
Beam Foundations
Minimum Width (Inches)*
1-story = 12 Inches
2-story = 15 Inches
3-story = 18 Inches
4-story = 21 Inches
1-story = 12 Inches
2-story = 15 Inches
3-story = 18 Inches
4-story = 21 Inches
Isolated Square or Column
Foundations
Minimum Width (Inches)*
1-story = 24 Inches
2-story = 30 Inches
3-story = 36 Inches
4-story = 42 Inches
1-story = 24 Inches
2-story = 30 Inches
3-story = 36 Inches
4-story = 42 Inches
Minimum Slab Thickness
(actual)1 4 – Actual 4 – Actual
Minimum Slab Reinforcing
6” x 6” – W1.4/W1.4 welded wire
fabric placed in middle of slab, or
No. 3 bars at 24-inch centers
6” x 6” – W2.9/W2.9 welded wire
fabric placed in middle of slab, or
No. 3 bars at 18-inch centers.
Minimum Footing
Reinforcement
Two No. 4 reinforcing bars,
one placed near the top and one
near the bottom
Two No. 5 reinforcing bars,
one placed near the top and one
near the bottom
Effective Plasticity Index <15 15<X<20
Presaturation of Subgrade Soil
(Percent of Optimum)
Minimum of 100% of the optimum
moisture content to a depth of at
least 12 inches prior to placing
concrete
Minimum of 110% of the optimum
moisture content to a depth of at
least 18 inches prior to placing
concrete
*Code minimums per Table 1809.7 of the 2019 CBC should be complied with.
It should be noted that the criteria provided are based on soil support characteristics only. The
structural engineer should design the slab and beam reinforcement based on actual loading
conditions.
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 21
Mat Slab Foundation
The mat slab foundation for the subterranean parking garage should have a minimum embedment
depth of 24 inches below lowest adjacent grade and may be designed using an allowable bearing
capacity of 4,500 psf. The recommended allowable soil bearing pressures may be increased by
one-third for temporary seismic or wind loading. Reinforcement within the mat foundation
should be determined by the structural engineer.
For resistance to lateral loads, an allowable coefficient of friction of 0.33 between the base of the
foundation elements. In addition, an allowable passive earth resistance equal to an equivalent
fluid weight of 300 pounds per cubic foot (pcf) for bedrock acting against the foundations may be
used to resist lateral forces. The top foot of passive resistance for foundations should be
neglected unless confined by pavement or slab.
A modulus of subgrade reaction (k-value) of 250 pounds per cubic inch (pci) may be considered
for design.
Under Slab Moisture Membrane
A moisture and vapor retarding system should be placed below slabs-on-grade where moisture
migration through the slab is undesirable. Guidelines for these are provided in the 2019 California
Green Building Standards Code (CALGreen) Section 4.505.2 and the 2019 CBC Section 1907.1
It should be realized that the effectiveness of the vapor retarding membrane can be adversely
impacted as a result of construction related punctures (e.g., stake penetrations, tears, punctures
from walking on the vapor retarder placed atop the underlying aggregate layer, etc.). These
occurrences should be limited as much as possible during construction. Thicker membranes are
generally more resistant to accidental puncture that thinner ones. Products specifically designed
for use as moisture/vapor retarders may also be more puncture resistant. Although the CBC
specifies a 6-mil vapor retarder membrane, it is GeoTek’s opinion that a minimum 10 mil
membrane with joints properly overlapped and sealed should be considered, unless otherwise
specified by the slab design professional.
Moisture and vapor retarding systems are intended to provide a certain level of resistance to
vapor and moisture transmission through the concrete, but do not eliminate it. The acceptable
level of moisture transmission through the slab is to a large extent based on the type of flooring
used and environmental conditions. Ultimately, the vapor retarding system should be comprised
of suitable elements to limit migration of water and reduce transmission of water vapor through
the slab to acceptable levels. The selected elements should have suitable properties (i.e.,
thickness, composition, strength, and permeability) to achieve the desired performance level.
5.3.6
5.3.7
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 22
Moisture retarders can reduce, but not eliminate, moisture vapor rise from the underlying soils
up through the slab. Moisture retarder systems should be designed and constructed in
accordance with applicable American Concrete Institute, Portland Cement Association, Post-
Tensioning Concrete Institute, ASTM and California Building Code requirements and guidelines.
GeoTek does not practice in the field of moisture vapor transmission evaluation/migration since
that practice is not a geotechnical discipline. Therefore, GeoTek recommends that a qualified
person, such as the flooring contractor, structural engineer, architect, and/or other experts
specializing in moisture control within the building be consulted to evaluate the general and
specific moisture and vapor transmission paths and associated potential impact on the proposed
construction. That person (or persons) should provide recommendations relative to the slab
moisture and vapor retarder systems and for migration of potential adverse impact of moisture
vapor transmission on various components of the structures, as deemed appropriate. In addition,
the recommendations in this report and GeoTek’s services in general are not intended to address
mold prevention; since GeoTek, along with geotechnical consultants in general, do not practice
in the area of mold prevention. If specific recommendations addressing potential mold issues are
desired, then a professional mold prevention consultant should be contacted.
Miscellaneous Foundation Recommendations
To reduce moisture penetration beneath the slab on grade areas, utility trenches
should be backfilled with engineered fill, lean concrete or concrete slurry where they
intercept the perimeter footing or thickened slab edge.
Spoils from the footing excavations should not be placed in the slab-on-grade areas
unless properly moisture-conditioned, compacted and tested. The excavations should
be free of loose/sloughed materials and be neatly trimmed at the time of concrete
placement.
Foundation Setbacks
Where applicable, the following setbacks should apply to all foundations. Any improvements not
conforming to these setbacks may be subject to lateral movements and/or differential
settlements:
The outside bottom edge of all footings should be set back a minimum of H/3 (where
H is the slope height) from the face of any descending slope. The setback should be
at least 7 feet and need not exceed 40 feet.
5.3.8
5.3.9
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 23
The bottom of all footings for structures near retaining walls should be deepened so
as to extend below a 1:1 projection upward from the bottom inside edge of the wall
stem. This applies to the existing retaining walls along the perimeter if they are to
remain.
The bottom of any existing foundations for structures should be deepened to extend
below a 1:1 projection upward from the bottom of the nearest excavation.
Seismic Design Parameters
The site is located at approximately 33.1632, degrees west latitude and -117.3443 degrees north
longitude. Site spectral accelerations (Ss and S1), for 0.2 and 1.0 second periods for a risk
targeted two (2) percent probability of exceedance in 50 years (MCER) were determined using
the web interface provided by SEAOC/OSHPD (https://seismicmaps.org) to access the USGS
Seismic Design Parameters. A risk category of II has been utilized as an input design parameter.
Due to the very apparent density of the underlying bedrock, a Site Class “C” is considered
appropriate for this site. The results, based on ASCE 7-16 and the 2019 CBC, are presented in
the following table.
SITE SEISMIC PARAMETERS
Mapped 0.2 sec Period Spectral Acceleration, Ss 1.064g
Mapped 1.0 sec Period Spectral Acceleration, S1 0.385g
Site Coefficient for Site Class “C”, Fa 1.2
Site Coefficient for Site Class “C”, Fv 1.5
Maximum Considered Earthquake (MCER) Spectral
Response Acceleration for 0.2 Second, SMS 1.276g
Maximum Considered Earthquake (MCER) Spectral
Response Acceleration for 1.0 Second, SM1 0.578g
5% Damped Design Spectral Response
Acceleration Parameter at 0.2 Second, SDS 0.851g
5% Damped Design Spectral Response
Acceleration Parameter at 1 second, SD1 0.385g
Site Modified Peak Ground Acceleration (PGAM) 0.562g
Seismic Design Category D
Soil Sulfate Content and Corrosivity
Sulfate content test results indicate water soluble sulfate is less than 0.1 percent by weight, which
is considered “S0” as per Table 19.3.1.1 of ACI 318-14. Based upon the test results, no special
recommendations for concrete are required for this project due to soil sulfate exposure.
5.3.10
5.3.11
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 24
Preliminary Pavement Design
Traffic indices have not been provided during this stage of site planning. In addition, site
conditions have not been graded to a final design to evaluate specific pavement subgrade
conditions. Therefore, the minimum structural sections provided below are based on a
preliminary laboratory R-Value of 25 and the assumed traffic indices.
PRELIMINARY ASPHALT PAVEMENT STRUCTURAL SECTION
Design Criteria Traffic Index
(TI)
Asphaltic Concrete (AC)
Thickness (inches)
Aggregate Base (AB)
Thickness (inches)
Driveway or
Perimeter Private 5.0 4.0 4.0
Grand Avenue
(Offsite Public Right
of Way)
5.0 4.0 4.0
Grand Avenue
(Offsite Public Right
of Way)
6.0 4.0 8.0
Actual structural pavement design is to be determined by the geotechnical engineer’s testing (R-
Value) of the exposed subgrade. Thus, the actual R-Value of the subgrade soils can only be
determined at the completion of grading for street subgrades and the above values are subject
to change based laboratory testing of the as-graded soils near subgrade elevations.
Asphalt concrete and aggregate base should conform to current Caltrans Standard Specifications
Section 39 and 26-1.02, respectively. As an alternative, asphalt concrete can conform to Section
203-6 of the current Standard Specifications for Public Work (Green Book). Crushed aggregate
base or crushed miscellaneous base can conform to Section 200-2.2 and 200-2.4 of the Green
Book, respectively. Pavement base should be compacted to at least 95 percent of the ASTM
D1557 laboratory maximum dry density as determined by ASTM D 1557 test procedures
All pavement installation, including preparation and compaction of subgrade, compaction of base
material, placement and rolling of asphaltic concrete, should be done in accordance with the City
of Carlsbad specifications, and under the observation and testing of GeoTek and a City Inspector
where required. Jurisdictional minimum compaction requirements in excess of the
aforementioned minimums may govern.
5.3.12
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 25
Portland Cement Concrete (PCC)
It is anticipated that Portland Cement Concrete (PCC) pavements will be utilized. Based on the
City of Carlsbad minimum design guidelines for driveways, the following recommended minimum
PCC pavement section is provided for these areas:
Ground floor of the parking structure
6 Inches Portland Cement Concrete (PCC) over
Santiago Formational Material Subgrade
Driveway into the parking structure or other structural surface pavement
7.5 Inches Portland Cement Concrete (PCC) over
6 Inches Aggregate Base (AB) over
12-inches subgrade compacted to 95% per ASTM D 1557
For the PCC options, it is recommended concrete having a minimum 28-day flexural strength (or
modulus of rupture (MOR)) of 650 psi be used. A “pavement”-type concrete mix (not a “slab”-
type) concrete mix should be use. Air-entrainment (5 ± 2 percent) of the concrete should be
provided. Sulfate resistant concrete is not required. A maximum joint spacing of 12 feet is also
recommended. Reinforcement of the concrete should be provided as recommended by the
structural engineer.
5.4 RETAINING WALL DESIGN AND CONSTRUCTION
General Design Criteria
Preliminary grading plans are not yet available. Retaining wall foundations embedded a minimum
of 18 inches into engineered fill or dense formational materials should be designed using an
allowable bearing capacity of 4,500 pounds per square foot (psf) may be used for design of
continuous and perimeter footings that meet the depth and width requirements in the table
above. This value may be increased by 300 pounds per square foot for each additional 12 inches
in depth and 200 pounds per square foot for each additional 12 inches in width to a maximum
value of 6,500 psf. Additionally, an increase of one-third may be applied when considering short-
term live loads (e.g., seismic and wind loads). Passive pressure may be computed as an equivalent
fluid having a density of 300 psf per foot of depth, to a maximum earth pressure of 4,500 psf for
footings founded on engineered fill. A coefficient of friction between soil and concrete of 0.33
may be used with dead load forces. Passive pressure and frictional resistance can be combined
without reduction.
5.3.13
5.4.1
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 26
An equivalent fluid pressure approach may be used to compute the horizontal active pressure
against the wall. The appropriate fluid unit weights are given in the table below for specific slope
gradients of retained materials.
Surface Slope of
Retained Materials
(H:V)
Equivalent Fluid Pressure
(PCF)
Select Backfill*
Level 40
2:1 65
*Select backfill should consist of approved materials with an
EI<20 and should be provided throughout the active zone.
The above equivalent fluid weights do not include other superimposed loading conditions such
as expansive soil, vehicular traffic, structures, seismic conditions or adverse geologic conditions.
Restrained Retaining Walls
Any retaining wall that will be restrained prior to placing backfill or walls that have male or
reentrant corners should be designed for at-rest soil conditions using an equivalent fluid pressure
of 65 pcf (select backfill), plus any applicable surcharge loading. For areas having male or reentrant
corners, the restrained wall design should extend a minimum distance equal to twice the height
of the wall laterally from the corner, or as otherwise determined by the structural engineer.
Seismic Earth Pressures on Retaining Walls
As required by the 2019 CBC, walls with a retained height greater than six feet are required to
include an incremental seismic earth pressure in the wall design. Based upon review, a wall with
a retained height of up to approximately 10 feet is planned at the site.
Based on the planned site wall heights and an SDS/2.5 value of 0.340g, the following incremental
seismic earth pressures may be used in the design of site walls greater than six feet in height:
Wall
Scenario
Additional Equivalent
Fluid Pressure (PCF)
Level Unrestrained 18H2
2:1 Sloping Backfill Unrestrained 29H2
Restrained 28H2
The point of application of the incremental seismic earth pressure is at 1/3H, where H is the
retained height.
5.4.2
5.4.3
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 27
Wall Backfill and Drainage
Wall backfill should include a minimum one (1) foot wide section of ¾ to 1-inch clean crushed
rock (or approved equivalent). The rock should be placed immediately adjacent to the back of
wall and extend up from the backdrain to within approximately 12 inches of finish grade. The
upper 12 inches should consist of compacted onsite materials. If the walls are designed using the
“select” backfill design parameters, then the “select” materials shall be placed within the active
zone as defined by a 1:1 (H:V) projection from the back of the retaining wall footing up to the
retained surface behind the wall. Presence of other materials might necessitate revision to the
parameters provided and modification of wall designs.
The backfill materials should be placed in lifts no greater than 8-inches in thickness and compacted
to a minimum of 90% of the maximum dry density as determined in accordance with ASTM Test
Method D 1557. Proper surface drainage needs to be provided and maintained. Water should
not be allowed to pond behind retaining walls. Waterproofing of site walls should be performed
where moisture migration through the wall is undesirable.
Retaining walls should be provided with an adequate pipe and gravel back drain system to reduce
the potential for hydrostatic pressures to develop. A 4-inch diameter perforated collector pipe
(Schedule 40 PVC, or approved equivalent) in a minimum of one (1) cubic foot per lineal foot of
3/8 to one (1) inch clean crushed rock or equivalent, wrapped in filter fabric should be placed
near the bottom of the backfill and be directed (via a solid outlet pipe) to an appropriate disposal
area.
As an alternative to the drain, rock and fabric, a pre-manufactured wall drainage product
(example: Mira Drain 6000 or approved equivalent) may be used behind the retaining wall. The
wall drainage product should extend from the base of the wall to within two (2) feet of the
ground surface. The subdrain should be placed in direct contact with the wall drainage product.
Drain outlets should be maintained over the life of the project and should not be obstructed or
plugged by adjacent improvements.
5.-4.4
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 28
6. CONCRETE FLATWORK
6.1 GENERAL CONCRETE FLATWORK
Exterior Concrete Slabs and Sidewalks
Exterior concrete slabs, sidewalks and driveways should be designed using a four-inch minimum
thickness with 6” x 6” – W1.4/W1.4 welded wire fabric, placed in the middle of slab. It is
recommended that control joints be placed in two directions spaced the numeric equivalent
roughly 24 times the thickness of the slab in inches (e.g., a 4-inch slab would have control joints
at 96 inch [8 feet] centers). These joints are a widely accepted means to control cracks and
should be reviewed by the project structural engineer. Some shrinkage and cracking of the
concrete should be anticipated as a result of typical mix designs and curing practices typically
utilized in construction.
Presaturation of flatwork subgrade should be verified to be a minimum of 100% of the soils
optimum moisture to a depth of 12 inches for soils having a “very low” expansive index potential.
Subgrade having a “low” expansion index potential should be verified to be moisture conditioned
to a minimum of 110% of the soils optimum moisture at a depth of 12 inches below subgrade.
7. POST CONSTRUCTION CONSIDERATIONS
7.1 LANDSCAPE MAINTENANCE AND PLANTING
Water has been shown to weaken the inherent strength of soil, and slope stability is significantly
reduced by overly wet conditions. Positive surface drainage away from graded slopes should be
maintained and only the amount of irrigation necessary to sustain plant life should be provided
for planted slopes. Controlling surface drainage and runoff and maintaining a suitable vegetation
cover can minimize erosion. Plants selected for landscaping should be lightweight, deep-rooted
types that require little water and are capable of surviving the prevailing climate.
Overwatering should be avoided. The soils should be maintained in a solid to semi-solid state as
defined by the materials Atterberg Limits. Care should be taken when adding soil amendments
to avoid excessive watering. Leaching as a method of soil preparation prior to planting is not
recommended. An abatement program to control ground-burrowing rodents should be
6.J.I
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 29
implemented and maintained. This is critical as burrowing rodents can decreased the long-term
performance of slopes.
It is common for planting to be placed adjacent to structures in planter or lawn areas. This will
result in the introduction of water into the ground adjacent to the foundation. This type of
landscaping should be avoided. If used, then extreme care should be exercised with regard to
the irrigation and drainage in these areas. Waterproofing of the foundation and/or subdrains may
be warranted and advisable. GeoTek could discuss these issues, if desired, when plans are made
available.
7.2 DRAINAGE
The need to maintain proper surface drainage and subsurface systems cannot be overly emphasized.
Positive site drainage should be maintained at all times. Drainage should not flow uncontrolled down
any descending slope. Water should be directed away from foundations and not allowed to pond
or seep into the ground adjacent to the footings. Site drainage should conform to Section 1804.4
of the 2019 CBC. Roof gutters and downspouts should discharge onto paved surfaces sloping away
from the structure or into a closed pipe system which outfalls to the street gutter pan or directly
to the storm drain system. Pad drainage should be directed toward approved areas and not be
blocked by other improvements.
7.3 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS
GeoTek recommends that site grading, specifications, retaining wall/shoring plans and foundation
plans be reviewed by this office prior to construction to check for conformance with the
recommendations of this report. Additional recommendations may be necessary based on these
reviews. It is also recommended that GeoTek representatives be present during site grading and
foundation construction to check for proper implementation of the geotechnical
recommendations. The owner/developer should have GeoTek’s representative perform at least
the following duties:
Observe site clearing and grubbing operations for proper removal of unsuitable materials.
Observe and test bottom of removals prior to fill placement.
Observe temporary shoring construction such as soldier beam excavation, basement
excavation, and tie-back installation.
Evaluate the suitability of on-site and import materials for fill placement and collect soil
samples for laboratory testing when necessary.
Observe the fill for uniformity during placement including utility trenches.
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 30
Observe and test the fill for field density and relative compaction.
Observe and probe foundation excavations to confirm suitability of bearing materials.
If requested, a construction observation and compaction report can be provided by GeoTek,
which can comply with the requirements of the governmental agencies having jurisdiction over
the project. GeoTek recommends that these agencies be notified prior to commencement of
construction so that necessary grading permits can be obtained.
8. LIMITATIONS
The scope of this evaluation is limited to the area explored that is shown on the Geotechnical
Map (Figure 2). This evaluation does not and should in no way be construed to encompass any
areas beyond the specific area of proposed construction as indicated to us by the client. The
scope is based on GeoTek’s understanding of the project and the client’s needs, GeoTek’s
proposal (Proposal No. P-0300822-SD) dated March 11th, 2022, and geotechnical engineering
standards normally used on similar projects in this region.
The materials observed on the project site appear to be representative of the area; however, soil
and bedrock materials vary in character between excavations and natural outcrops, or conditions
exposed during site construction. Site conditions may vary due to seasonal changes or other
factors. GeoTek, Inc. assumes no responsibility or liability for work, testing or recommendations
performed or provided by others.
Since GeoTek’s recommendations are based on the site conditions observed and encountered,
and laboratory testing, GeoTek’s conclusions and recommendations are professional opinions
that are limited to the extent of the available data. Observations during construction are
important to allow for any change in recommendations found to be warranted. These opinions
have been derived in accordance with current standards of practice and no warranty is expressed
or implied. Standards of practice are subject to change with time.
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page 31
9. SELECTED REFERENCES
American Society of Civil Engineers (ASCE), 2016, “Minimum Design Loads for Buildings and
Other Structures,” ASCE/SEI 7-16.
ASTM International (ASTM), “ASTM Volumes 4.08 and 4.09 Soil and Rock.”
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.
California Code of Regulations, Title 24, 2019 “California Building Code,” 2 volumes.
California Geological Survey (CGS, formerly referred to as the California Division of Mines and
Geology), 1977, “Geologic Map of California.”
____, 1998, “Maps of Known Active Fault Near-Source Zones in California and Adjacent
Portions of Nevada,” International Conference of Building Officials.
GeoTek, Inc., In-house proprietary information.
Kennedy, M.P., and Tan, S.S., 2007, “Geologic Map of the Oceanside 30x60-minute Quadrangle,
California,” California Geological Survey, Regional Geologic Map No. 2, map scale
1:100,000.
Pasco Laret Suiter and Associates, 2022, “Preliminary Site Exhibit”
Structural Engineers Association of California/California Office of Statewide Health Planning and
Development (SEOC/OSHPD), 2019, Seismic Design Maps web interface,
https://seismicmaps.org
Soil Web Survey.com
Terzaghi, K. and Peck, R., 1967, “Soil Mechanics in Engineering Practice”, second edition.
U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey
Handbook, Title 210, Part 630, Chapter 7, Hydrologic Soil Groups.
GEOTEK
Carlsbad Village II, LLC
950 Carlsbad Village Drive
APNs: 203-320-20, -02, -48, -51, -40, -41
Carlsbad, California 1384 Poinsettia Avenue, Suite A
Vista, California 92081
Figure 1
Site Location Map
N
Not to Scale
Imagery from US Forestry Service, 2022
Approximate Site
Location
PN: 3780-SD DATE: April 2022
GEOTEK
Source: Preliminary Site Exhibi, Pasco Laret Suiter & Associates
Scale:
1384 Poinsettia Avenue, Suite A, Vista, CA 92081
(760) 599-0509 (phone) / (760) 599-0593 (FAX)
GEOTECHNICAL | ENVIRONMENTAL | MATERIALS
5/9/22
FIGURE 2
GEOTECHNICAL MAP
HOPE APARTMENTS
1009 CARLSBAD VILLAGE DRIVE
CARLSBAD, CALIFORNIA
Project No.:Report Date:Drawn By:
3780-SD CDL
N
Af
276
Amelia
Site
Improvements
Artificial
Fill
Test Pit
Exploration
B-1
B-2
B-3
B-4
B-5
B-6
P-1
P-2
?
?
?
?
?
?
Af
Af
Af
Af
Af
Qop
Qop
Qop
Tsa
Tsa
LEGEND
Approximate Site Boundary
Cross Section
Approximate Location of Exploratory Boring
Approximate Location of Percolation Test
Approximate Geologic Contact, dashed where
buried, queried where inferred.
Af Artificial Fill
Qop Old Paralic Deposits, Circled Where Buried
Tsa Santigo Formation , Circled Where Buried
B-6
P-2
A A’
B’
B
B’B
............ ., ..
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GEOTEK
PIAN VIEW· PRELIMINARY SITE EXHIBIT
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Hope Apartments
PN: 3780-SD Figure 3
Cross Section A-A’
May 2022
(E)
Topography
Proposed
Basement
W-E
0
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A
A’
30
60
90
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30
60
90
Qop
Tsa Tsa
Af
B-1 B-4 B-5
Cross Section B-B’
TD = 50’
TD = 30’
TD = 16’???
??
LEGEND
Approximate Geologic Contact, dashed where
buried, queried where inferred.
Approximate Groundwater Elevation
Af Artificial Fill
Qop Old Paralic Deposits
Tsa Santiago Formation
I t--------'-------------,------------,--_J·-----------:----------------------------~------
' ' '
' '
' ' ' ' ' ' ---------------------------------------------:----------------------- ---------------_,
' ' ~ ----------------------- ----------------------------------------------·
I I -
---- --- - --------· t-----
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-
Hope Apartments
PN: 3780-SD Figure 4
Cross Section B-B’
May 2022
(E)
Topography
Proposed
Basement
N-S
0
El
e
v
a
t
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(
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)
B
B’
30
60
90
0
30
60
90
Qop
Tsa
Af
B-1 B-6
Cross Section
A-A’
TD = 50’
TD = 20’
??
TD = 30’
Qop
Tsa
LEGEND
Approximate Geologic Contact, dashed where
buried, queried where inferred.
Approximate Groundwater Elevation
Af Artificial Fill
Qop Old Paralic Deposits
Tsa Santiago Formation
I I
--- - - --- - - - - - - - - - -- - - - - ------ -- -- - - - --- - -~ - -- - - -- ----- -- - -- - - - - - - - - - - - - --- ----- -- - - - -- - - - - - - - - - - --- --T --- - - - - -- - - - - - --- --- - - ------ - - - ---- - - - - - ---
' : ' ' ' ' ---------r:::.:.:.:.::::.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :.-r--------- - - - - ------ - - - -- ----- - - - --- - - - - - - -
.--
APPENDIX A
LOGS OF EXPLORATION
AND
PERCOLATION WORKSHEETS
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, San Diego County, California Page A-1
A - FIELD TESTING AND SAMPLING PROCEDURES
Bulk Samples (Large)
These samples are normally large bags of earth materials over 20 pounds in weight collected
from the field by means of hand digging or exploratory cuttings.
Bulk Samples (Small)
These samples are normally small bags of earth materials less than 10 pounds in weight collected
from the field by means of hand digging or exploratory cuttings.
Ring Samples
B – BORING/TRENCH LOG LEGEND
The following abbreviations and symbols often appear in the classification and description of soil
and rock on the logs of borings/trenches:
SOILS
USCS Unified Soil Classification System
f-c Fine to coarse
f-m Fine to medium
GEOLOGIC
B: Attitudes Bedding: strike/dip
J: Attitudes Joint: strike/dip
C: Contact line
……….. Dashed line denotes USCS material change
Solid Line denotes unit / formational change
Thick solid line denotes end of boring/trench
(Additional denotations and symbols are provided on the log of borings/trenches)
GEOTEK
GeoTek, Inc.
LOG OF EXPLORATORY BORING
BB-1 SP
SM
18 R-1 SM
18
33 3.2 107.9
30 S-1 SM
50/9 11.2
50/6 R-2 SM 16.5 113.5
50/5 S-2 19.8
50/4 R-3 SH
50/6 S-3 11.2
---Small Bulk ---No Recovery ---Water Table
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30 Silty fine SANDSTONE, gray, wet, dense
LE
G
E
N
D
Sample type: ---Ring ---SPT ---Large Bulk
Lab testing:
25 Silty fine SANDSTONE, gray, wet, dense, well cemented
20 Santiago Formation (Tsa)
Mud coming out of cuttings
Silty fine to medium SANDSTONE, gray, wet, very dense
Water on sampling rod
15 Silty fine to medium SAND, brown to reddish brown, moist, very dense
10 Silty fine to medium SAND, brown to reddish brown, moist, very dense
Fine SAND, brown, dry, soft, roots
Old Paralic Deposits (Qop)
Silty fine to medium SAND, light brown, dry, loose, trace gravels
5 Silty fine to medium SAND, brown to reddish brown, dry, very dense
Dr
y
D
e
n
s
i
t
y
(p
c
f
)
Ot
h
e
r
s
MATERIAL DESCRIPTION AND COMMENTS
Artificial Fill (Af)
SAMPLES
US
C
S
S
y
m
b
o
l
BORING NO.: B-1
Laboratory Testing
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Blo
w
s
/
6
i
n
Sa
m
p
l
e
Nu
m
b
e
r
Wa
t
e
r
C
o
n
t
e
n
t
(%
)
LOCATION:Carlsbad, CA ELEVATION:63 feet DATE:4/6/2022
PROJECT NO.:3780-SD HAMMER:140lbs/30in RIG TYPE:CME-75
PROJECT NAME:Hope Apartments DRILL METHOD:6" Dia Hollowstem Auger OPERATOR:Manny
CLIENT:Carlsbad Village II, LLC DRILLER:Baja Exploration LOGGED BY:MRF
J ------,...._ --_,_ ------
:0
--------------¥ -----
-U --------_,__
----------
-□
■ I 12] [8J □ ¥
GeoTek, Inc.
LOG OF EXPLORATORY BORING
50/3 R-4 16.4 117.9
50/5 S-4 15.8
50/2 R-2 10.6 131.9
50/2 S-5 13.6
---Small Bulk ---No Recovery ---Water Table
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
60
LE
G
E
N
D
Sample type: ---Ring ---SPT ---Large Bulk
Lab testing:
55
Groundwater encountered at 17 feet during drilling
Static Groundwater Observed at 3pm is 10.3'
Static Groundwater Observed On 4/7 at 7am is 9.8'
50 Clayey fine SANDSTONE, brownish gray, moist, very dense
HOLE TERMINATED AT 50.1 FEET
45 Silty fine SANDSTONE, grayish brown, moist, cemented very dense
40 Silty fine to medium SANDSTONE, wet, very dense, friable
35 Silty fine SANDSTONE, gray, wet, very dense
Dr
y
D
e
n
s
i
t
y
(p
c
f
)
Ot
h
e
r
s
MATERIAL DESCRIPTION AND COMMENTS
SAMPLES
US
C
S
S
y
m
b
o
l
BORING NO.: B-1 Cont.
Laboratory Testing
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Blo
w
s
/
6
i
n
Sa
m
p
l
e
Nu
m
b
e
r
Wa
t
e
r
C
o
n
t
e
n
t
(%
)
LOCATION:Carlsbad, CA ELEVATION:63 feet DATE:4/6/2022
PROJECT NO.:3780-SD HAMMER:140lbs/30in RIG TYPE:CME-75
PROJECT NAME:Hope Apartments DRILL METHOD:6" Dia Hollowstem Auger OPERATOR:Manny
CLIENT:Carlsbad Village II, LLC DRILLER:Baja Exploration LOGGED BY:MRF
-------------------------
:□ ---------------------n
-------------------
■ I 12] [8J □ ~
GeoTek, Inc.
LOG OF EXPLORATORY BORING
SM
---Small Bulk ---No Recovery ---Water Table
PROJECT NAME:Hope Apartments DRILL METHOD:6" Dia Hollowstem Auger OPERATOR:Manny
CLIENT:Carlsbad Village II, LLC DRILLER:Baja Exploration LOGGED BY:CDL
LOCATION:Carlsbad, CA ELEVATION:63 feet DATE:4/6/2022
PROJECT NO.:3780-SD HAMMER:140lbs/30in RIG TYPE:CME-75
SAMPLES
US
C
S
S
y
m
b
o
l
BORING NO.: B-2
Laboratory Testing
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Blo
w
s
/
6
i
n
Sa
m
p
l
e
Nu
m
b
e
r
Wa
t
e
r
C
o
n
t
e
n
t
(%
)
Artificial Fill (Af)
Silty fine SAND, dark reddish brown, moist, loose
Hand Auger:
1st Hole - Encounter direct burial wire
Dr
y
D
e
n
s
i
t
y
(p
c
f
)
Ot
h
e
r
s
MATERIAL DESCRIPTION AND COMMENTS
Planter - 2 inches of mulch
2nd Hole - 18 inches east, plastic pipe
3rd Hole - 18 inches east, vcp
5 Hole Abandoned
10
15
20
25
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30
LE
G
E
N
D
Sample type: ---Ring ---SPT ---Large Bulk
Lab testing:
-----------------------------------------------------------
■ I 12] [8J □ ~
GeoTek, Inc.
LOG OF EXPLORATORY BORING
BB-1 SM
MD, SH
SR
15 R-1 SM
18
23
11 S-1 SM
13
15 8.1
27 R-2 SP
28
45 SH
50/5 S-2 23.3
50/2 R-3 14.9 115.5
50/5 S-3
---Small Bulk ---No Recovery ---Water Table
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30 HOLE TERMINATED AT 30.5 FEET
Groundwater encountered at 10 feet
LE
G
E
N
D
Sample type: ---Ring ---SPT ---Large Bulk
Lab testing:
Silty fine SANDSTONE, pale gray, moist, very dense
25 Silty fine to medium SANDSTONE, gray brown, wet, very dense
20 Santiago Formation (Tsa)
Silty fine SANDSTONE, light gray, wet, very dense, sluff
Poorly graded medium SAND, brown, wet, very dense, trace well round large
gravel
Large well round gravel in cuttings, driling slows, standing rig
15 Poorly graded coarse SAND, black, wet, very dense
stem is wet
10 Silty fine to medium SAND, reddish brown, moist, dense, outside sampler and
Silty fine SAND, dark reddish brown, moist
Silty fine SAND, dark reddish brown, moist, faint palsofacies
Silty fine SAND, dark brown, moist, brick fragments
5 Old Paralic Deposits (Qop)
Artificial Fill (Af)
Silty medium to coarse SAND (Decomposed Granite), brown, moist
Dr
y
D
e
n
s
i
t
y
(p
c
f
)
Ot
h
e
r
s
MATERIAL DESCRIPTION AND COMMENTS
Asphalt 3 inches over subgrade
SAMPLES
US
C
S
S
y
m
b
o
l
BORING NO.: B-3
Laboratory Testing
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Blo
w
s
/
6
i
n
Sa
m
p
l
e
Nu
m
b
e
r
Wa
t
e
r
C
o
n
t
e
n
t
(%
)
LOCATION:Carlsbad, CA ELEVATION:69 feet DATE:4/6/2022
PROJECT NO.:3780-SD HAMMER:140lbs/30in RIG TYPE:CME-75
PROJECT NAME:Hope Apartments DRILL METHOD:6" Dia Hollowstem Auger OPERATOR:Manny
CLIENT:Carlsbad Village II, LLC DRILLER:Baja Exploration LOGGED BY:CDL
-: \ / --
: / \ ---
----------~f ------
----------
-U --------_,__
-----------n ---
■ I 12] [8J □ ~
GeoTek, Inc.
LOG OF EXPLORATORY BORING
SM
SM
9 S-1 SM
10
18 8.1
15 R-1
50/5 SH
50/2 S-2 11.1
50/2 R-2
50/6 S-3 7.5
7.9
50/5 S-4
---Small Bulk ---No Recovery ---Water Table
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30 HOLE TERMINATED AT 30.5 FEET
Groundwater encountered at 19 feet
LE
G
E
N
D
Sample type: ---Ring ---SPT ---Large Bulk
Lab testing:
Silty fine SANDSTONE, pale olive brown, moist to very moist
25 inside of auger plugged
Silty fine SANDSTONE, pale olive brown, moist to very moist
20 Mud cuttings, no recovery
Very hard drilling, slow advancement, footings might be difficult to excavate
Well rounded GRAVEL in cuttings and increased moisture
15 Silty fine SANDSTONE, olive brown, moist, low sample recovery
10 Silty fine SANDSTONE, olive brown, moist, oxidized staining
Santiago Formation (Tsa)
Silty fine SANDSTONE, light brownish gray, moist, medium dense
5 Silty fine to medium SAND, dark brown, moist
Artificial Fill (Afu)
Silty medium to coarse SAND (Decomposed Granite), reddish brown, moist,
large gravel
Silty fine SAND, dark brown
Dr
y
D
e
n
s
i
t
y
(p
c
f
)
Ot
h
e
r
s
MATERIAL DESCRIPTION AND COMMENTS
Asphalt 2 inches over subgrade
SAMPLES
US
C
S
S
y
m
b
o
l
BORING NO.: B-4
Laboratory Testing
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Blo
w
s
/
6
i
n
Sa
m
p
l
e
Nu
m
b
e
r
Wa
t
e
r
C
o
n
t
e
n
t
(%
)
LOCATION:Carlsbad, CA ELEVATION:69 feet DATE:4/6/2022
PROJECT NO.:3780-SD HAMMER:140lbs/30in RIG TYPE:CME-75
PROJECT NAME:Hope Apartments DRILL METHOD:6" Dia Hollowstem Auger OPERATOR:Manny
CLIENT:Carlsbad Village II, LLC DRILLER:Baja Exploration LOGGED BY:CDL
--------
-17
:U ------------------
:□ ----------:~ ----------
=□ -------..... •·············· -
-□·
□ D 12] [8J □ ~
GeoTek, Inc.
LOG OF EXPLORATORY BORING
BB-1
SM SR
SM
8 R-1 SM
17
35 10.6 121.7
12 S-1
16
18 4.4
30 S-2
50/5 8.0
---Small Bulk ---No Recovery ---Water Table
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30
LE
G
E
N
D
Sample type: ---Ring ---SPT ---Large Bulk
Lab testing:
25
20
HOLE TERMINATED AT 16 FEET
Percured groundwater at 10 feet?
Increased density, harder drilling
15 Sitly fine SANDSTONE, olive gray, moist, friable, some oxidized stained fractures
sample is friable
10 Clayey SANDSTONE, mottled olive gray and olive brown, very moist, very dense,
Santiago Formation (Tsa)
Silty fine SANDSTONE, light blue gray, very moist, very dense
Silty fine SAND, dark brown, moist
5 Silty fine SAND, dark brown, moist
Artificial Fill (Afu)
Silty medium to coarse SAND with gravel (Decomposed Granite), reddish brown
Dr
y
D
e
n
s
i
t
y
(p
c
f
)
Ot
h
e
r
s
MATERIAL DESCRIPTION AND COMMENTS
Asphalt 3 inches over subgrade
SAMPLES
US
C
S
S
y
m
b
o
l
BORING NO.: B-5
Laboratory Testing
De
p
t
h
(
f
t
)
Sa
m
p
l
e
T
y
p
e
Blo
w
s
/
6
i
n
Sa
m
p
l
e
Nu
m
b
e
r
Wa
t
e
r
C
o
n
t
e
n
t
(%
)
LOCATION:Carlsbad, CA ELEVATION:69 feet DATE:4/6/2022
PROJECT NO.:3780-SD HAMMER:140lbs/30in RIG TYPE:CME-75
PROJECT NAME:Hope Apartments DRILL METHOD:6" Dia Hollowstem Auger OPERATOR:Manny
CLIENT:Carlsbad Village II, LLC DRILLER:Baja Exploration LOGGED BY:CDL
J ------,...._ ----------
~□ ------
=n
----------------------------
■ I 12] [8J □ ~
GeoTek, Inc.
LOG OF EXPLORATORY BORING
BB-1 SP RV
0'-20'
SM
10 S-1 SM
23
30
50/5 S-2 SM
50/6 S-3
50/3 S-4
---Small Bulk ---No Recovery ---Water Table
PROJECT NAME:Hope Apartments DRILL METHOD:6" Dia Hollowstem Auger OPERATOR:Manny
CLIENT:Carlsbad Village II, LLC DRILLER:Baja Exploration LOGGED BY:CDL
LOCATION:Carlsbad, CA ELEVATION:63 feet DATE:4/6/2022
PROJECT NO.:3780-SD HAMMER:140lbs/30in RIG TYPE:CME-75
SAMPLES
US
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b
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BORING NO.: B-6
Laboratory Testing
De
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Nu
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Fine SAND, brown, dry, soft, roots
Old Paralic Deposits (Qop)
Silty fine to medium SAND, light brown, dry, loose, trace gravels
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MATERIAL DESCRIPTION AND COMMENTS
Artificial Fill (Af)
5 Silty fine to medium SAND, light brown
Cuttings show increase in moisture
10 Silty fine to medium SAND, light reddish brown, wet, very dense
Silty fine SANDSTONE, olive gray, very moist
15 Santiago Formation (Tsa)
Groundwater encountered at 10 feet
Backfilled with soil cuttings
20 Silty fine SANDSTONE, olive gray, very moist
HOLE TERMINATED AT 20 FEET
25
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30
LE
G
E
N
D
Sample type: ---Ring ---SPT ---Large Bulk
Lab testing:
---
-----
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Job No.: 3780-SD .
Date: 4/7/22 .
After Test: 48"
Reading
No.Time
Time
Interval
(Min)
Total
Depth of
Hole
(Inches)
Initial
Water
Level
(Inches)
Final
Water
Level
(Inches)
∆ In Water
Level
(Inches)
Comments
1 7:30 30 48 20 31 11
2 8:00 30 48 23 34 11
3 8:30 30 48 23 33 10
4 9:00 30 48 24 34 10
5 9:30 30 48 28 35 7
6 10:00 30 48 24.25 30.75 6.5
7 10:30 30 48 20.75 28.25 7.5
8 11:00 30 48 21.50 27.00 5.5
9 11:30 30 48 20.75 26.25 5.5
10 12:30 30 48 19.75 24.25 4.5
11 13:00 30 48 20.25 25.50 5.25
12 13:30 30 48 18.75 24.00 5.25
13 14:00 30 48 19.25 24.25 5
PERCOLATION DATA SHEET
Project: Hope Avenue
Test Hole No.: P-1 Tested By: CDL ,
Depth of Hole As Drilled: 48" Before Test: ___48"______________________
Equation -It =
Havg = (HO+HF)/2 =
It = Inches per Hour
Time Interval, Δt = 30
Client:
Project:
Project No:3780-SD
Date:4/7/2022
Boring No.P-1
Infiltration Rate (Porchet Method)
Carlsbad Village II, LLC
Hope Avenue Apartments
Final Depth to Water, DF =24.25
Test Hole Radius, r =3.00
Initial Depth to Water, DO =19.25
0.54
Total Test Hole Depth, DT = 48
ΔH (60r)
Δt (r+2Havg)
HO = DT - DO = 28.75
HF = DT - DF = 23.75
ΔH = ΔD = HO- HF = 5.00
26.25
GEOTEK
Job No.: 3780-SD .
Date: 4/7/22 .
After Test: 48"
Reading
No.Time
Time
Interval
(Min)
Total
Depth of
Hole
(Inches)
Initial
Water
Level
(Inches)
Final
Water
Level
(Inches)
∆ In Water
Level
(Inches)
Comments
1 7:15 30 54 24 32 8
2 7:45 30 54 20 28 8
3 8:15 30 54 22 29 7
4 8:45 30 54 23 30 7
5 9:15 30 54 20.25 28 7.75
6 9:45 30 54 21.50 27.75 6.25
7 10:15 30 54 22.50 28.75 6.25
8 10:45 30 54 21.25 27.75 6.5
9 11:15 30 54 23.25 29.50 6.25
10 11:45 30 54 22.75 29.25 6.5
11 12:15 30 54 21.50 28.50 7
12 12:45 30 54 20.75 26.25 5.5
13 13:15 30 54 21.25 27.00 5.75
PERCOLATION DATA SHEET
Project: Hope Avenue
Test Hole No.: P-2 Tested By: CDL ,
Depth of Hole As Drilled: 54" Before Test: ___54"______________________
Carlsbad Village II, LLC
Equation -It =
Havg = (HO+HF)/2 =
It = Inches per Hour
Time Interval, Δt = 30
Client:
Project:
Project No:3780-SD
Date:4/7/2022
Boring No.P-2
Infiltration Rate (Porchet Method)
Hope Avenue Apartments
Final Depth to Water, DF =27.00
Test Hole Radius, r =3.00
Initial Depth to Water, DO =21.25
0.55
Total Test Hole Depth, DT = 54
ΔH (60r)
Δt (r+2Havg)
HO = DT - DO = 32.75
HF = DT - DF = 27.00
ΔH = ΔD = HO- HF = 5.75
29.88
GEOTEK
APPENDIX B
RESULTS OF LABORATORY TESTING
GEOTEK
CARLSBAD VILLAGE II, LLC Project No. 3780-SD
Preliminary Geotechnical Evaluation July 28, 2022
Proposed Hope Apartments, Carlsbad, California Page B-1
SUMMARY OF LABORATORY TESTING
Identification and Classification
Soils were identified visually in general accordance with the standard practice for description and
identification of soils (ASTM D 2488). The soil identifications and classifications are shown on
the Logs of Exploration in Appendix A.
Moisture Density Modified Proctor
Laboratory testing was performed on one sample collected during the subsurface exploration for
compaction characteristics. The laboratory maximum dry density and optimum moisture content
for the soil was determined in general accordance with ASTM Test Method D 1557 procedures.
The test results are graphically presented in Appendix B.
Full Corrosion Suite
A full corrosion series was performed in general accordance with several ASTM Test Methods.
The samples were obtained from Test Pit TP-6 and TP-7 and tested by Project X Engineering.
Atterberg Limits
The tests were performed in general accordance with ASTM D 4318. The test results are
presented in Appendix B.
Percent of Soil Passing No 200 Sieve
The amount of soil finer than No. 200 sieve was determined for two sandy samples collected
from the site. The tests were performed in general accordance with ASTM D 1140. The test
results are presented in Appendix B.
Direct Shear
Shear testing was performed in a direct shear machine of the strain-control type in general
accordance with ASTM Test Method D 3080 procedures. The rate of deformation is
approximately 0.35 inches per minute. The samples were sheared under varying confining loads
to determine the coulomb shear strength parameters, angle of internal friction and cohesion.
One test was performed on a bulk sample that was remolded to approximately 90 percent of the
maximum dry density as determined by ASTM D 1557. The results of the testing are graphically
presented in Appendix B.
GEOTEK
Job No.
Client
Project
Location
Tested by:
15 20 28 37
1 2 1 2 3 4
0.00 0.00 0.00 0.00 0.00 0
0.00 0.00 0.00 0.00 0.00 0
0.00 0.00 0.00 0.00 0.00 0.00
0.85 0.85 0.86 0.86 0.86 0.86
-0.85 -0.85 -0.86 -0.86 -0.86 -0.86
0.0 0.0 0.0 0.0 0.0 0.0
0
0
0
3780-SD
Carlsbad Village II, LLC
Hope Apartments
950 Carlsbad Village Drive
Number of Blows
Plastic Limit
Light Brown Silty Sand
B-5 BB-1
Sample Type
CH
Wt. of Dry Soil
Plasticity Index
Moisture Content %
Liquid Limit Graph
Liquid Limit
Plastic Limit
Liquid Limit
ATTERBERG LIMITS DATA
Wt. of Dish + Dry Soil
Wt. of Moisture
Wt. of Dish
Field Classification
Dish
Wt. of Dish + Wet Soil
Sample Number
Determination
Big Bulk
20.0
22.0
24.0
26.0
28.0
30.0
32.0
34.0
36.0
38.0
40.0
10 100
Mo
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%
Number of Drops
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60 70 80 90 100
Pl
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Liquid Limit
CL
ML & OL
CH
MH & CH
CL-ML
GEOTEK
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MOISTURE/DENSITY RELATIONSHIP
Client:Carlsbad Village II, LLC Job No.:3780-SD
Project:Hope Apartments Lab No.:Corona
Location:-
Material Type:Light brown silty sand
Material Supplier:-
Material Source:-
Sample Location:B3 @ .-20'
-
Sampled By:CL Date Sampled:-
Received By:MP Date Received:-
Tested By:RL Date Tested:5/2/2022
Reviewed By:DA Date Reviewed:5/5/2022
Test Procedure:ASTM D1557 Method:A
Oversized Material (%):0.1 Correction Required: yes no
MOISTURE CONTENT (%):4.384134 6.837607 8.695652 10.61947 4.379749 6.830769 8.6869565 10.60885
DRY DENSITY (pcf):120.8846 128.519 130.0374 126.5191
CORRECTED DRY DENSITY (pcf):0 0 0 0
ZERO AIR VOIDS DRY DENSITY (pcf):
MOISTURE DENSITY RELATIONSHIP VALUES
Maximum Dry Density, pcf 130.0 @ Optimum Moisture, %8.5
Corrected Maximum Dry Density, pcf @ Optimum Moisture, %
MATERIAL DESCRIPTION
Grain Size Distribution:Atterberg Limits:
% Gravel (retained on No. 4)Liquid Limit, %
% Sand (Passing No. 4, Retained on No. 200)Plastic Limit, %
% Silt and Clay (Passing No. 200)Plasticity Index, %
Classification:
Unified Soils Classification:
110
112
114
116
118
120
122
124
126
128
130
132
134
136
138
140
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
DR
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N
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,
P
C
F
MOISTURE CONTENT, %
MOISTURE/DENSITY RELATIONSHIP CURVE DRY DENSITY (pcf):
CORRECTED DRY DENSITY (pcf):
ZERO AIR VOIDS DRY DENSITY (pcf)
S.G. 2.7
S.G. 2.8
S.G. 2.6
Poly. (DRY DENSITY (pcf):)
OVERSIZE CORRECTED
ZERO AIR VOIDS
Poly. (S.G. 2.7)
Poly. (S.G. 2.8)
Poly. (S.G. 2.6)
GEOTEK
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Hope Apartments Sample Location:
Date Tested:
Shear Strength:F =26 O , C = 540 psf
Notes:
5/3/2022
DIRECT SHEAR TEST
2 - The above reflect direct shear strength at saturated conditions.
1 - The soil specimen used in the shear box was a ring sample remolded to approximately 90% relative compaction from a
bulk sample collected during the field investigation.
Project Name:
Project Number:
3 - The tests were run at a shear rate of 0.35 in/min.
3780-SD
B-3 @ 0-3 feet
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
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GEOTEK
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Hope Apartments Sample Location:
Date Tested:
Shear Strength:F =27 O , C = 797 psf
Notes:1 - The soil specimen used in the shear box was a ring sample remolded to approximately 90% relative compaction from a
bulk sample collected during the field investigation.
2 - The above reflect direct shear strength at saturated conditions.
3 - The tests were run at a shear rate of 0.01 in/min.
PEAK VALUE
DIRECT SHEAR TEST
Project Name:B-3 @ 0-3 feet
Project Number: 3780-SD 5/3/2022
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
SH
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T
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S
S
(
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NORMAL STRESS (psf)
GEOTEK
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I I I I I I I I I t I t t I t I I t I t I I t I I t I t I I t I I t I t t t I I I I I t I I I t I t t t I I t I t t t I I t I t t t I I t I t t t I I t I t t I t I I t I t I t I -------------'-------------1..------------""-------------"---------_..,_ ____________ ... ____________ ...,L. ____________ ., I t I t t I t I I t I t I I t I I t I t I I t I I t I t t I t I I I I t I I I I t I t I t I I t I t I t I I t I t I t I I t I t I t I I t I t I t I I t I I I t I I t t I I t I -------------t-------------1-----------~-------------t------------+------------t------------+------------i
I t I t I I t I : + : : : : : : I I t t I t I I I t t I t I I I t t I t I I I t t I t I I I t t I t I I I t I I t I I I t I I t I --------------~------------~-------------+------------+------------+------------+------------~ I t I t t I t I I I I I t I I I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t I I t I I t I t I I t I I t I t t I t I I t I t I I t I I t I t I I t I ------------"T-------------r------------,-------------r------------,-------------T------------"'T"------------, I I I I t I I I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t I I t I I t I t I I t I I t I t t I t I I t I t I I t I I t I t I I t I
Hope Apartments Sample Location:
Date Tested:
Shear Strength:F =32.1 O , C = 244.00 psf
Notes:
DIRECT SHEAR TEST
Project Name:B-1 @ 25 feet
Project Number: 3780-SD 4/22/2022
1 - The soil specimens sheared were "undisturbed" ring samples.
2 - The above reflect direct shear strength at saturated conditions.
3 - The tests were run at a shear rate of 0.01 in/min.
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
SH
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S
T
R
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S
S
(
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NORMAL STRESS (psf)
GEOTEK
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: : : • I : : : -------------t-------------1-------------~-----------------------+------------t------------+------------i
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ------------~-------------~----------~-------------+------------+------------+------------+------------~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -"T-------------r------------,-------------r------------,-------------T------------"'T"------------, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
Hope Apartments Sample Location:
Date Tested:
Shear Strength:F =32.6 O , C = 859.50 psf
Notes:
DIRECT SHEAR TEST
Project Name:B-1 @ 25 feet
Project Number: 3780-SD 4/22/2022
PEAK VALUE
1 - The soil specimens sheared were "undisturbed" ring samples.
2 - The above reflect direct shear strength at saturated conditions.
3 - The tests were run at a shear rate of 0.01 in/min.
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
SH
E
A
R
S
T
R
E
S
S
(
p
s
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)
NORMAL STRESS (psf)
GEOTEK
------------.,-------------r-------------,-------------r------------.,-------------,-------------,-------------, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ------------.,-------------r-------------,-------------r------------..,-------------T------------"'T"------------, I I I I I I I I I I I I I I I I I I I I I I • I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
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I t I I t I I t t I t I I I t I I I I t t I t I I t t I t I I t t I t I I t t I t I I t t I t I I t I I t I I t I I t I ------~-------------~------------~-------------+------------+------------+------------+------------~ I t I t t I t I I I I I t I I I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t I I t I I t I t I I t I I t I t t I t I I t I t I I t I I t I t I I t I ------------"T-------------r------------,-------------r------------,-------------T------------"'T"------------, I I I I t I I I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t I I t I I t I t I I t I I t I t t I t I I t I t I I t I I t I t I I t I
Hope ApartmentsSample Location:
Date Tested:
Shear Strength:F =37.4O , C = 562.50 psf
Notes:
2 - The above reflect direct shear strength at saturated conditions.
Project Name:
Project Number: 3780-SD
B-3 @ 15 feet
4/22/2022
DIRECT SHEAR TEST
3 - The tests were run at a shear rate of 0.035 in/min.
1 - The soil specimens sheared were "undisturbed" ring samples.
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
SH
E
A
R
S
T
R
E
S
S
(
p
s
f
)
NORMAL STRESS (psf)
I I I I I I I I I I I I I I I I I I I I I I I I I L------------..L.------------.I.-------------L------------J.-------------L------------.J-------------1.------------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ~------------+------------+-------------!-------------+-------------~------------➔-----------t------------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I T I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ~------------+------------+------------+------------~-------------~---------i-------------~------------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I r------------""T'"------------T-------------r------------.,-----------.--------------,-------------r------------1 I I I I I I I I t I t I t I I t I t I t I I t I t I t I I t I t I t I I t I t I t I I t I I I t I I t I t I t I I I I t I I I I I I t I I I I t I t I t I I t I t I t I 1-------------1"""------------1"-----------1--------------t-------------1--------------1-------------t-------------l t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I I t I t I I t I t t I t I I I I t I I I I I I t I I I I I t I t t I t I I I I t I I I I I I I t I I I I 1-------------~----------+---------------------------.. -------------1----------------------------+-------------I t I t t I t I I t I t t I t I I t I t t I t I I t I t t I t I I t I I t I t I I I t t I t I I I t I I I I I I t I I I I I I t t I t I I I t I I I I I I t I I I I I t I t t I t I L--_______ ....., ____________ ,a. ____________ -'---------------i-------------L------------.J-------------'-------------
'
t I t t I t I t I t t I t I t I t t I t I t I I t I t I t I t t I t I t I t t I t I t I t t I t I t I t t I t I t I t t I t I t I t t I t I I I t I I I I I I I t I I I I '-------------..J-------------.1.-------------'---------------'-------------L------------..I-------------'-------------
>131.J..031~
tr
Hope Apartments Sample Location:
Date Tested:
Shear Strength:F =45.7 O , C = 953.50 psf
Notes:
DIRECT SHEAR TEST
Project Name:B-3 @ 15 feet
Project Number: 3780-SD 4/22/2022
PEAK VALUE
1 - The soil specimens sheared were "undisturbed" ring samples.
2 - The above reflect direct shear strength at saturated conditions.
3 - The tests were run at a shear rate of 0.035 in/min.
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
4500.0
5000.0
5500.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0 4500.0 5000.0 5500.0
SH
E
A
R
S
T
R
E
S
S
(
p
s
f
)
NORMAL STRESS (psf)
GEOTEK
--------T---------,---------,---------,---------,.---------r---------r--------T---------,---------,---------, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --------~---------1---------~---------"---------·---------~---------1-----------------1---------~----------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --------"T"'---------,---------,---------T---------,----------r--------r---------r---------,----------,---------, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --------..L.--------J---------.l---------.L---------.1.-----------------L.--------·--------.J---------.J---------J I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --------...... --------... ---------1---------... -----------------.. ---------1----------r--------... ---------;---------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
--------+---------l----------l-----------------t---------t---------~--------+---------l----------l---------~
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --------~---------(-----------------+---------•---------►---------1----------P---------f---------◄----------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --------+--------I --------➔---------+---------t---------~---------1---------+--------~---------➔---------~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I _______ .,1 _________ ., _________ ... ___________________ .,. _________ "" ________ ....... ________ .,1 _________ " _________ .,
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -------'T"---------,---------,---------T---------,----------r---------r---------,----------,----------,---------, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --------..L.--------"'---------..1---------.L---------.L---------'----------L.--------·--------"'---------..1---------J I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
Hope ApartmentsSample Location:
Date Tested:
Shear Strength:F =33.3O , C = 232.50 psf
Notes:
DIRECT SHEAR TEST
Project Name:B-4 @ 10 feet
Project Number: 3780-SD4/22/2022
1 - The soil specimens sheared were "undisturbed" ring samples.
2 - The above reflect direct shear strength at saturated conditions.
3 - The tests were run at a shear rate of 0.01 in/min.
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
SH
E
A
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T
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(
p
s
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)
NORMAL STRESS (psf)
I I I I I I I I I I I I I I I I I I I I I I I I I L------------..L.------------.I.-------------L------------J.-------------L------------.J-------------1.-1 I I I I I I •
I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I : : : : : : ' I I I I I I I I I I I I I I I I I I I ~------t------~------4------~------~---, ·i-------------t------------, I I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ~------------+------------+------------+------------¼ ----------~------------i-------------~------------I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I r------------~------------T-----------r------------.,-------------.--------------,-------------r------------1 I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I i-------------1 I I I I t
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ------------1"------------~-------------t-------------1--------------1-------------t-------------l I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1-------------~------------+---------------------------.. -------------1----------------------------+-------------I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I L ____________ ....., ____________ ,a. ____________ -'---------------i-------------L------------.J-------------'-------------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I '-------------..J-------------.1.-------------'---------------'-------------L------------..I-------------'-------------
>131.J..031~
tr
Hope Apartments Sample Location:
Date Tested:
Shear Strength:F =37.8 O , C = 709.00 psf
Notes:
DIRECT SHEAR TEST
Project Name:B-4 @ 10 feet
Project Number: 3780-SD 4/22/2022
PEAK VALUE
1 - The soil specimens sheared were "undisturbed" ring samples.
2 - The above reflect direct shear strength at saturated conditions.
3 - The tests were run at a shear rate of 0.01 in/min.
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0
SH
E
A
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S
T
R
E
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S
(
p
s
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)
NORMAL STRESS (psf)
GEOTEK
------------.,-------------r-------------,-------------r------------.,-------------,-------------,-------------, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I • I I I I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I ------------.,-------------r-------------,-------------r------------..,-------------T------------"'T"----------, 1 I I I I I t I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -------------t----------------------------1-------------t--------------------------+------------~------------➔ l I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I t I t I ------------1-------------:------------1-----------·+----------~------------~------------~------------~ I I I I t I t I • I I I I I I I I I I I I I I I I I I I t I t I I I I I I I I I I I I I I I I I I t I t I I I I I I I I I I I I I I I I I I t t I t I I I I I I I I I -------------'-------------1..------------J-----------~------------~------------~------------~------------J I I I t t I t I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ------------i-------------1 I I I I I I I I
I I I I I t t I t I I I I I I I I I I I t t I t I I I I I I I I I I I t t I t I I I I I I I I I I I I -----------i-------------t------------+------------t------------+------------i
I I I I I I I t t I t I I I I I I I I I I I I I I t t I t I I I I I I I I I I I I I I t t I t I I I I I I I I I I I I I --~-------------~------------~-------------+------------+------------+------------+------------~ I t I t t I t I I I I I I I I I I I I I I I I I I t I t t I t I I I I I I I I I I I I I I I I I I t I t t I t I I I I I I I I I I I I I I I I I I t I t t I t I I I I I I I I I I I I I I I I I ------------"T-------------r------------,-------------r------------,-------------T------------"'T"------------, I I I I I I I I I I I I I I I I I t I t t I t I I I I I I I I I I I I I I I I I I t I t t I t I I I I I I I I I I I I I I I I I I t I t t I t I I I I I I I I I I I I I I I I I
0'-20'
• ANALYSIS
• DESIGN l.4aallelle • ,\\:119\iH .-----PROFESSIONAL PAVEMENT ENGINEERING
April 21, 2022
Mr. Chris Livesey
GeoTek Inc.
1384 Poinsettia Avenue Suite A
Vista, CA 92081 -8505
Dear Mr. Livesey:
A CALIFORNIA CORPORATION
Project No. 48199
• SOILS, ASPHALT
TECH NOLOGY
Laboratory testing of the bulk soil sample delivered to our laboratory on 4/19/2022
has been completed.
Reference:
Project:
Sample:
W.O. # 3780-SD
1006 Carlsbad Village Drive
B-6, BB-1 @ o~ ,.~ . • . l
I
Data sheets and graphical pre~entatio*s are tnmsmitted,,herewith for your use and
information. Any untested portion of:thy samples will be,Tetained for a period of
sixty (60) days prior to di;pos'al: The opport:urtity ~9 b·e. of ~ervice is appreciated,
and should you have ~.P.Y qu·estions,;ldp.dly call:, , '
! '1 ·. j, ' .• :, '. • •
' , i , '\
en R. Marvin
RCE 30659
SRM:tw
Enclosures
'
2700 S. GRAND AVENUE • SANTA ANA, CA 92705-5404 • (714) 546-3468 • FAX (714) 546-5841
IN FO@LABELLEMARVIN.COM
0'-20'
LI\/\
LaBelle Marvin
PROJECT No.
DATE:
BORING NO.
R -VALUE
48199
4/21/2022
B-6, BB-1@ O'f
1006 Carlsbad Village Drive
W.O.# 3780-SD
SAMPLE DESCRIPTION: Brown Silty Sand
DATA SHEET
-- - ----------R-VALUE TESTING DATA I CA TEST 301-
Mold ID Number
Water added, grams
Initial Test Water, %
Compact Gage Pressure,psi
Exudation Pressure, psi
Height Sample, Inches
Gross Weight Mold, grams
Tare Weight Mold, grams
Sample Wet Weight, grams
Expansion, Inches x 10exp-4
Stability 2,000 lbs (160psi)
Turns Displacement
R-Value Uncorrected
R-Value Corrected
Dry Density, pcf
Traffic In dex
G.E. by Stability
G. E. by Expansion
Equilibrium R-Value
Gf =
SPECIMEN ID
a b
7 8
71 so
12.0 9.9
45 130
190 431
2.55 2.49
3113 3084
1950 1946
1163 1138
0 15
43 I 103 25 / 53
4.13 3.90
25 56
25 56
123.4 126.0
DESIGN CALCULATION DATA
Assumed: 4.0
1.25
0.77
0.00
42
by
EXUDATION
4.0
0.45
0.50
0.1% Retained on the
REMARKS: 3/4" Sieve.
C
9
35
8.5
340
744
2.48
2895
1770
1125
28
16 / 30
3.73
74
74
126.7
4.0
0.27
0.93
4 /21/ 22
The data above is based upon processing and testing samples as received from the field. Test procedures in
accordance with latest revisions to Department of Transportation, State of California, Materials & Research Test
Method No. 301.
LaBelle Marvin, Inc. I 2700 South Grand Avenue I Santa Ana, CA 92705 I 714-514-3565
0'-20'
LI\/\
LaBelle Marvin
PROJECT NO.
DATE:
BORING NO.
R-VALUE GRAPHICAL PRESENTATION
48199
4 /21/ 2022 REMARKS:
B-6, BB-1 @0'4-(...._-------1 .__ _______________ _
1006 Carlsbad Village Drive
W.O.# 3780-SD
---~ -- -------------------------COVER THICKNESS BY EXUDATION vs COVER THICKNESS BY EXPANSION
t z 0 ~ 0 :::,
~
>-Cl
"' "' z :.: u :i: ,_
ffi > s
800
0.0
700 600
0.5 1.0
500 400 300 200 100
1.5 2.0 2.5 3.0 3.5 4.0
COVER THICKNESS BY EXPANSION, FT.
■ EXUD. T vs. Expan. T lo R-VALUE vs. EXUD. PRES.
----------------
400
350
"' 300 C: ~ :;:
"' 200 g
< ~ 0 u
COMPACTOR PRESSURE vs MOISTURE%
• " • -t -···,-t-==
-·---. -H~-:· -~ ---~-. -·-+-.·-±~±::+=;· ~---::t::::j::_ :---=! . -+---i-J ::=1= ::::·+:=t:
... .......... -·--~,--+-: -+ ··--r---r--·-
-, ::is,_.,_,, --. --.. i-----·-. ·-·--: ~-i:~-+---~ ---· __ ,_-i--•--~. _-----~·-·
,___.. __ _. .. --r-... --_ _.__ --1---~t
:··:== ~::l --- --·~:-= ::::p~::;+
-1"' r.:::=t:,_ -+-· ==+==t-
: i---· '...J..., i--, '
·r·•·+· · ' ... :::!. :::q::---+ I+ -, . "--=F
~:-~·:: j=~=:iS::1:_=~ -~ =~~ ~: ~~;:~~~: =r ~~
7.5 8.5 9.5 10.5 11.5 12.5
MOISTURE (%) AT FABRICAJTON
---------------- ----
COVER THICKNESS vs MOISTURE%
7.5 8.5 9.5 10.5 11.5 12.5
MOISTURE(%)
A EXPANSION ■EXUDATION
Project X REPORT S220414J
Corrosion Engineering Page 1
Corrosion Control – Soil, Water, Metallurgy Testing Lab
29990 Technology Dr, Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720
www.projectxcorrosion.com
Results Only Soil Testing
for
Hope Apartments
April 18, 2022
Prepared for:
Chris Livesey
GeoTek, Inc.
1384 Poinsettia Ave, Suite A
Vista, CA, 92081
clivesey@geotekusa.com
Project X Job#: S220414J
Client Job or PO#: 3780-SD
Respectfully Submitted,
Eduardo Hernandez, M.Sc., P.E.
Sr. Corrosion Consultant
NACE Corrosion Technologist #16592
Professional Engineer
California No. M37102
ehernandez@projectxcorrosion.com
Project X REPORT S220414J
Corrosion Engineering Page 2
Corrosion Control – Soil, Water, Metallurgy Testing Lab
29990 Technology Dr., Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720
www.projectxcorrosion.com
Soil Analysis Lab Results
Client: GeoTek, Inc.
Job Name: Hope Apartments
Client Job Number: 3780-SD
Project X Job Number: S220414J
April 18, 2022
Method ASTM G51 ASTM
G200
SM 4500-D ASTM
D4327
ASTM
D6919
ASTM
D6919
ASTM
D6919
ASTM
D6919
ASTM
D6919
ASTM
D6919
ASTM
D4327
ASTM
D4327
Bore# / Description Depth pH Redox Sulfide
S2-
Nitrate
NO3-
Ammonium
NH4+
Lithium
Li+
Sodium
Na+
Potassium
K+
Magnesium
Mg2+
Calcium
Ca2+
Fluoride
F2--
Phosphate
PO43-
(ft)(mg/kg)(wt%)(mg/kg)(wt%)(Ohm-cm)(Ohm-cm)(mV)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)
B-3 BB-1 0-3 9.7 0.0010 3.4 0.0003 308,200 8,710 9.0 105 0.12 0.2 8.9 ND 93.1 4.2 21.9 8.3 0.7 0.2
B-5 BB-1 0-3 16.2 0.0016 8.0 0.0008 10,720 4,556 9.3 116 0.12 0.0 0.7 ND 73.4 4.5 21.1 10.0 2.1 2.3
ASTM
G187
ASTM
D4327
ASTM
D4327
Resistivity
As Rec'd | Minimum
Sulfates
SO42-
Chlorides
Cl-
Cations and Anions, except Sulfide and Bicarbonate, tested with Ion Chromatography
mg/kg = milligrams per kilogram (parts per million) of dry soil weight
ND = 0 = Not Detected | NT = Not Tested | Unk = Unknown
Chemical Analysis performed on 1:3 Soil-To-Water extract
PPM = mg/kg (soil) = mg/L (Liquid)
Lab Roqucst Shttt Chlia of Custody Phone: \213)9211-7213 • ~·a,<(9S1)226·1720 • www.projccrxconosion.com Ship Samples To: 29990 Technology Dr, Suite 13, Murrieta, CA 92563 rroJttt X Job Number 52.2_0
Conipaay Namo: Geo T ek, Inc.
Mallinr;Addrns: 1384 Poinsetta Ave, Ste A, Vista, CA 92081
Accounrinr; Conlwct:
Clirnt Proj«t No:
P.0.11:
Results By: 0 Pbon• 0 .. ,., 13 Email
Date & Rtttiv<d by :
2fuf
CoataclNamo: Chris Livesey PhonoNo: 949-338-9233
i-------,--,,--...,~-1111-,-<'_•"'°""--,-·-•...,!lt,--rnct-,' ,---r--,.--..--.--,---i ~ 1--R-•..,sio,_r1_,_-i
;:,, ~ :~ c ..
0 .!!! ·;;; " a.. C: u .. :2 .. 0 ., a! a 0 ;( "0 E ~ 0 I.:: ·o ::c = :c '0 "5 E u z .,, .. "' u ~ .,, <
.,
" E .. ;;; E g :, '0 "" ·;;; ·c 51-:,
£ .. :, ~ .. 0 0
~
.., 0 :.: a.. :.:i .,,
E :, -~ E :,
iii, ·.; .. ;;; ~ LI
... ;;;
C
,e .. u
czi
·i:; ::, "'
APPENDIX C
GENERAL EARTHWORK GRADING GUIDELINES
GEOTEK
GENERAL GRADING GUIDELINES APPENDIX C
Page C-1
GENERAL GRADING GUIDELINES
Guidelines presented herein are intended to address general construction procedures for earthwork
construction. Specific situations and conditions often arise which cannot reasonably be discussed in
general guidelines, when anticipated these are discussed in the text of the report. Often unanticipated
conditions are encountered which may necessitate modification or changes to these guidelines. It is our
hope that these will assist the contractor to more efficiently complete the project by providing a
reasonable understanding of the procedures that would be expected during earthwork and the testing
and observation used to evaluate those procedures.
General
Grading should be performed to at least the minimum requirements of governing agencies, Chapters 18
and 33 of the California Building Code, CBC (2019) and the guidelines presented below.
Preconstruction Meeting
A preconstruction meeting should be held prior to site earthwork. Any questions the contractor has
regarding our recommendations, general site conditions, apparent discrepancies between reported and
actual conditions and/or differences in procedures the contractor intends to use should be brought up
at that meeting. The contractor (including the main onsite representative) should review our report
and these guidelines in advance of the meeting. Any comments the contractor may have regarding these
guidelines should be brought up at that meeting.
Grading Observation and Testing
1. Observation of the fill placement should be provided by our representative during grading.
Verbal communication during the course of each day will be used to inform the contractor of
test results. The contractor should receive a copy of the "Daily Field Report" indicating results
of field density tests that day. If our representative does not provide the contractor with these
reports, our office should be notified.
2. Testing and observation procedures are, by their nature, specific to the work or area observed
and location of the tests taken, variability may occur in other locations. The contractor is
responsible for the uniformity of the grading operations; our observations and test results are
intended to evaluate the contractor’s overall level of efforts during grading. The contractor’s
personnel are the only individuals participating in all aspect of site work. Compaction testing
and observation should not be considered as relieving the contractor’s responsibility to properly
compact the fill.
3. Cleanouts, processed ground to receive fill, key excavations, and subdrains should be observed
by our representative prior to placing any fill. It will be the contractor's responsibility to notify
our representative or office when such areas are ready for observation.
4. Density tests may be made on the surface material to receive fill, as considered warranted by
this firm.
5. In general, density tests would be made at maximum intervals of two feet of fill height or every
1,000 cubic yards of fill placed. Criteria will vary depending on soil conditions and size of the fill.
More frequent testing may be performed. In any case, an adequate number of field density tests
should be made to evaluate the required compaction and moisture content is generally being
obtained.
6. Laboratory testing to support field test procedures will be performed, as considered warranted,
based on conditions encountered (e.g. change of material sources, types, etc.) Every effort will
GEOTEK
GENERAL GRADING GUIDELINES APPENDIX C
Page C-2
be made to process samples in the laboratory as quickly as possible and in progress construction
projects are our first priority. However, laboratory workloads may cause in delays and some
soils may require a minimum of 48 to 72 hours to complete test procedures.
Whenever possible, our representative(s) should be informed in advance of operational changes
that might result in different source areas for materials.
7. Procedures for testing of fill slopes are as follows:
a) Density tests should be taken periodically during grading on the flat surface of the fill,
three to five feet horizontally from the face of the slope.
b) If a method other than over building and cutting back to the compacted core is to be
employed, slope compaction testing during construction should include testing the outer
six inches to three feet in the slope face to determine if the required compaction is
being achieved.
8. Finish grade testing of slopes and pad surfaces should be performed after construction is
complete.
Site Clearing
1. All vegetation, and other deleterious materials, should be removed from the site. If material is
not immediately removed from the site it should be stockpiled in a designated area(s) well
outside of all current work areas and delineated with flagging or other means. Site clearing
should be performed in advance of any grading in a specific area.
2. Efforts should be made by the contractor to remove all organic or other deleterious material
from the fill, as even the most diligent efforts may result in the incorporation of some materials.
This is especially important when grading is occurring near the natural grade. All equipment
operators should be aware of these efforts. Laborers may be required as root pickers.
3. Nonorganic debris or concrete may be placed in deeper fill areas provided the procedures used
are observed and found acceptable by our representative.
Treatment of Existing Ground
1. Following site clearing, all surficial deposits of alluvium and colluvium as well as weathered or
creep effected bedrock, should be removed unless otherwise specifically indicated in the text of
this report.
2. In some cases, removal may be recommended to a specified depth (e.g. flat sites where partial
alluvial removals may be sufficient). The contractor should not exceed these depths unless
directed otherwise by our representative.
3. Groundwater existing in alluvial areas may make excavation difficult. Deeper removals than
indicated in the text of the report may be necessary due to saturation during winter months.
4. Subsequent to removals, the natural ground should be processed to a depth of six inches,
moistened to near optimum moisture conditions and compacted to fill standards.
5. Exploratory back hoe or dozer trenches still remaining after site removal should be excavated
and filled with compacted fill if they can be located.
Fill Placement
1. Unless otherwise indicated, all site soil and bedrock may be reused for compacted fill; however,
some special processing or handling may be required (see text of report).
2. Material used in the compacting process should be evenly spread, moisture conditioned,
processed, and compacted in thin lifts six (6) to eight (8) inches in compacted thickness to
GEOTEK
GENERAL GRADING GUIDELINES APPENDIX C
Page C-3
obtain a uniformly dense layer. The fill should be placed and compacted on a nearly horizontal
plane, unless otherwise found acceptable by our representative.
3. If the moisture content or relative density varies from that recommended by this firm, the
contractor should rework the fill until it is in accordance with the following:
a) Moisture content of the fill should be at or above optimum moisture. Moisture should
be evenly distributed without wet and dry pockets. Pre-watering of cut or removal
areas should be considered in addition to watering during fill placement, particularly in
clay or dry surficial soils. The ability of the contractor to obtain the proper moisture
content will control production rates.
b) Each six-inch layer should be compacted to at least 90 percent of the maximum dry
density in compliance with the testing method specified by the controlling governmental
agency. In most cases, the testing method is ASTM Test Designation D 1557.
4. Rock fragments less than eight inches in diameter may be utilized in the fill, provided:
a) They are not placed in concentrated pockets;
b) There is a sufficient percentage of fine-grained material to surround the rocks;
c) The distribution of the rocks is observed by, and acceptable to, our representative.
5. Rocks exceeding eight (8) inches in diameter should be taken off site, broken into smaller
fragments, or placed in accordance with recommendations of this firm in areas designated
suitable for rock disposal. On projects where significant large quantities of oversized materials
are anticipated, alternate guidelines for placement may be included. If significant oversize
materials are encountered during construction, these guidelines should be requested.
6. In clay soil, dry or large chunks or blocks are common. If in excess of eight (8) inches minimum
dimension, then they are considered as oversized. Sheepsfoot compactors or other suitable
methods should be used to break up blocks. When dry, they should be moisture conditioned to
provide a uniform condition with the surrounding fill.
Slope Construction
1. The contractor should obtain a minimum relative compaction of 90 percent out to the finished
slope face of fill slopes. This may be achieved by either overbuilding the slope and cutting back
to the compacted core, or by direct compaction of the slope face with suitable equipment.
2. Slopes trimmed to the compacted core should be overbuilt by at least three (3) feet with
compaction efforts out to the edge of the false slope. Failure to properly compact the outer
edge results in trimming not exposing the compacted core and additional compaction after
trimming may be necessary.
3. If fill slopes are built "at grade" using direct compaction methods, then the slope construction
should be performed so that a constant gradient is maintained throughout construction. Soil
should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain grades.
Compaction equipment should compact each lift along the immediate top of slope. Slopes
should be back rolled or otherwise compacted at approximately every 4 feet vertically as the
slope is built.
4. Corners and bends in slopes should have special attention during construction as these are the
most difficult areas to obtain proper compaction.
5. Cut slopes should be cut to the finished surface. Excessive undercutting and smoothing of the
face with fill may necessitate stabilization.
GEOTEK
GENERAL GRADING GUIDELINES APPENDIX C
Page C-4
UTILITY TRENCH CONSTRUCTION AND BACKFILL
Utility trench excavation and backfill is the contractors responsibility. The geotechnical consultant
typically provides periodic observation and testing of these operations. While efforts are made to make
sufficient observations and tests to verify that the contractors’ methods and procedures are adequate to
achieve proper compaction, it is typically impractical to observe all backfill procedures. As such, it is
critical that the contractor use consistent backfill procedures.
Compaction methods vary for trench compaction and experience indicates many methods can be
successful. However, procedures that “worked” on previous projects may or may not prove effective
on a given site. The contractor(s) should outline the procedures proposed, so that we may discuss
them prior to construction. We will offer comments based on our knowledge of site conditions and
experience.
1. Utility trench backfill in slopes, structural areas, in streets and beneath flat work or hardscape
should be brought to at least optimum moisture and compacted to at least 90 percent of the
laboratory standard. Soil should be moisture conditioned prior to placing in the trench.
2. Flooding and jetting are not typically recommended or acceptable for native soils. Flooding or
jetting may be used with select sand having a Sand Equivalent (SE) of 30 or higher. This is
typically limited to the following uses:
a) shallow (12 + inches) under slab interior trenches and,
b) as bedding in pipe zone.
The water should be allowed to dissipate prior to pouring slabs or completing trench
compaction.
3. Care should be taken not to place soils at high moisture content within the upper three feet of
the trench backfill in street areas, as overly wet soils may impact subgrade preparation.
Moisture may be reduced to 2% below optimum moisture in areas to be paved within the upper
three feet below sub grade.
4. Sand backfill should not be allowed in exterior trenches adjacent to and within an area
extending below a 1:1 projection from the outside bottom edge of a footing, unless it is similar
to the surrounding soil.
5. Trench compaction testing is generally at the discretion of the geotechnical consultant. Testing
frequency will be based on trench depth and the contractors procedures. A probing rod would
be used to assess the consistency of compaction between tested areas and untested areas. If
zones are found that are considered less compact than other areas, this would be brought to
the contractors attention.
JOB SAFETY
General
Personnel safety is a primary concern on all job sites. The following summaries are safety considerations
for use by all our employees on multi-employer construction sites. On ground personnel are at highest
risk of injury and possible fatality on grading construction projects. The company recognizes that
construction activities will vary on each site and that job site safety is the contractor's responsibility.
However, it is, imperative that all personnel be safety conscious to avoid accidents and potential injury.
In an effort to minimize risks associated with geotechnical testing and observation, the following
precautions are to be implemented for the safety of our field personnel on grading and construction
projects.
GEOTEK
GENERAL GRADING GUIDELINES APPENDIX C
Page C-5
1. Safety Meetings: Our field personnel are directed to attend the contractor's regularly scheduled
safety meetings.
2. Safety Vests: Safety vests are provided for and are to be worn by our personnel while on the job
site.
3. Safety Flags: Safety flags are provided to our 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.
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. The primary concern is the technician's
safety. However, it is necessary to take sufficient tests at various locations to obtain a representative
sampling of the fill. As such, efforts will be made to coordinate locations with the grading contractors
authorized representatives (e.g. dump man, operator, supervisor, grade checker, etc.), and to select
locations following or behind the established traffic pattern, preferably outside of current traffic. The
contractors authorized representative should direct excavation of the pit and safety during the test
period. Again, safety is the paramount concern.
Test pits should be excavated so that the spoil pile is placed away from oncoming traffic. The
technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates that the
fill be maintained in a drivable condition. Alternatively, the contractor may opt to park a piece of
equipment in front of test pits, particularly in small fill areas or those with limited access.
A zone of non-encroachment should be established for all test pits (see diagram below). No grading
equipment should enter this zone during the test procedure. The zone should extend outward to the
sides approximately 50 feet from the center of the test pit and 100 feet in the direction of traffic flow.
This zone is established both for safety and to avoid excessive ground vibration, which typically
decreases test results.
50 ft Zone of
Non-Encroachment
50 ft Zone of
Non-Encroachment
Traffic Direction
Vehicle
parked here Test Pit Spoil
pile
Spoil
pile
Test Pit
SIDE VIEW
PLAN VIEW
TEST PIT SAFETY PLAN
10 0 ft Zone of
Non-Encroachment
'~
...,
'. ·~
\..
I
•
GEOTEK
GENERAL GRADING GUIDELINES APPENDIX C
Page C-6
Slope Tests
When taking slope tests, the technician should park their vehicle directly above or below the test
location on the slope. The contractor's representative should effectively keep all equipment at a safe
operation distance (e.g. 50 feet) away from the slope during 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.
Trench Safety
It is the contractor's responsibility to provide safe access into trenches where compaction testing is
needed. Trenches for all utilities should be excavated in accordance with CAL-OSHA and any other
applicable safety standards. Safe conditions will be required to enable compaction testing of the trench
backfill.
All utility trench excavations in excess of 5 feet deep, which a person enters, are to be shored or laid
back. Trench access should be provided in accordance with OSHA standards. Our personnel are
directed not to enter any trench by being lowered or "riding down" on the equipment.
Our personnel are directed not to enter any excavation which;
1. is 5 feet or deeper unless shored or laid back,
2. exit points or ladders are not provided,
3. displays any evidence of instability, has any loose rock or other debris which could fall into the
trench, or
4. displays any other evidence of any unsafe conditions regardless of depth.
If the contractor fails to provide safe access to trenches for compaction testing, our company policy
requires that the soil technician withdraws and notifies their supervisor. The contractors representative
will then be contacted in an effort to effect a solution. All backfill not tested due to safety concerns or
other reasons is subject to reprocessing and/or removal.
Procedures
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 directed to inform both the developer's and
contractor's representatives. If the condition is not rectified, the technician is required, by company
policy, to immediately withdraw and notify their supervisor. The contractor’s representative will then
be contacted in an effort to effect a solution. No further testing will be performed until the situation is
rectified. Any fill placed in the interim 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 technicians attention and notify our project
manager or office. Effective communication and coordination between the contractors' representative
and the field technician(s) is strongly encouraged in order to implement the above safety program and
safety in general.
The safety procedures outlined above should be discussed at the contractor's safety meetings. This will
serve to inform and remind equipment operators of these safety procedures particularly the zone of
non-encroachment.
GEOTEK
GENERAL GRADING GUIDELINES APPENDIX C
Page C-7
The safety procedures outlined above should be discussed at the contractor's safety meetings. This will
serve to inform and remind equipment operators of these safety procedures particularly the zone of
non-encroachment.
GEOTEK
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008
APPENDIX C
Summary outputs of Global Slope Stability
GEOTEK
1.661.66
300.00 lbs/ft2
1.661.66
HOPE AVE
Min FSMethod Name
1.66Bishop simplified
1.71Spencer
1.65GLE / MorgensternPrice
Ru
Value
Water
Surface
Allow Sliding
Along Boundary
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit
Weight
(lbs/ft3)
ColorMaterial
Name
0None26500Mohr
Coulomb126Af
0None33200Mohr
Coulomb122Qop
0None32225Mohr
Coulomb137Tsa
0NoneNoInfinite
Strength120Shoring
Wall
-20 -10 0 10 20 30 40 50 60 70 80
AnalysisGroupGEOTECHNICAL
Company GeoTek, Inc.Drawn By ERC
File Name Cross Section CC'_Hope Ave.slimDate4/3/2024
Project:
HOPE APARTMENTS
SLIDEINTERPRET 9.029
0 t--
0 (C)
0 LO
0 s:t
0 (')
0 N
0 .....
LJ
I I
■
□
□
□
. rocsc 1en ce >-------------->--------------------,1
1.411.41
300.00 lbs/ft2
1.411.41
0.15
Min FSMethod Name
1.41Bishop simplified
1.45Spencer
1.41GLE / MorgensternPrice
Ru
Value
Water
Surface
Allow Sliding Along
Boundary
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit Weight
(lbs/ft3)ColorMaterial
Name
0None26500Mohr
Coulomb126Af
0None33200Mohr
Coulomb122Qop
0None32225Mohr
Coulomb137Tsa
0NoneNoInfinite
Strength120Shoring
Wall
-20 -10 0 10 20 30 40 50 60 70 80
AnalysisGroupGEOTECHNICAL
Company GeoTek, Inc.Drawn By ERC
File Name Cross Section CC'_Hope Ave.slimDate4/3/2024
Project:
HOPE APARTMENTS
SLIDEINTERPRET 9.029
0 r--
0 <O
0 s:t
0 (')
0 N
0 .....
LJ
■
□
□
[:J
. rocsc 1en ce>-------------------------------,1
1.771.77
300.00 lbs/ft2
1.771.77
GRAND AVE.
Min FSMethod Name
1.77Bishop simplified
1.80Spencer
1.79GLE / MorgensternPrice
Ru
Value
Water
Surface
Allow Sliding Along
Boundary
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit Weight
(lbs/ft3)ColorMaterial
Name
0None26500Mohr
Coulomb126Af
0None33200Mohr
Coulomb122Qop
0None32225Mohr
Coulomb137Tsa
0NoneNoInfinite
Strength120Shoring
Wall
-20 -10 0 10 20 30 40 50 60 70 80
AnalysisGroupGEOTECHNICAL
Company GeoTek, Inc.Drawn By ERC
File Name Cross Section DD'_Grand Ave.slimDate4/3/2024
Project:
HOPE APARTMENTS
SLIDEINTERPRET 9.029
0 r--
0
<O
0 s:t
0 (")
0 N
0 .....
I I
■
■
□
■
'--r--T----r--,~~~~~~~~~~~~~~~~~~~~~~~~~~--,----y--i
LJ . rocsc 1en ce >-------------------------------,1
1.481.48 300.00 lbs/ft21.481.48
GRAND AVE.
Min FSMethod Name
1.48Bishop simplified
1.50Spencer
1.48GLE / MorgensternPrice
Ru
Value
Water
Surface
Allow Sliding Along
Boundary
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit Weight
(lbs/ft3)ColorMaterial
Name
0None26500Mohr
Coulomb126Af
0None33200Mohr
Coulomb122Qop
0None32225Mohr
Coulomb137Tsa
0NoneNoInfinite
Strength120Shoring
Wall
0.15
-20 -10 0 10 20 30 40 50 60 70 80
AnalysisGroupGEOTECHNICAL
Company GeoTek, Inc.Drawn By ERC
File Name Cross Section DD'_Grand Ave.slimDate4/3/2024
Project:
HOPE APARTMENTS
SLIDEINTERPRET 9.029
0 r--
0
<O
0 s:t
0 (")
0 N
0 .....
I I
~
■
□
□
□
'--r--T---r-r-~~~~~~~~~~~~~~~~~~~~~~~~~~
LJ . rocsc 1en ce >-------------------------------,1
Response to Comments April 4, 2024
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008
APPENDIX D
GeoTek’s Referenced October 23, 2023 Report
GEOTEK
GEOTECHNICAL | ENVIRONMENTAL | MATERIAL
October 23, 2023
Project No. 3780-SD
Wermers Companies
5120 Shoreham Place, Suite 150
San Diego, CA 92122
Attention: Mr. Patrick Zabrocki
Subject: Supplemental Geotechnical Recommendation
APN 203-320-20, -02, -48, -51, 40, and -41
Carlsbad Village Drive and Hope Avenue
Carlsbad, California 92008
Dear Mr. Zabrocki:
As requested, GeoTek, Inc. (GeoTek) is providing supplemental geotechnical recommendations
for on-site retaining walls and mat foundation design. These recommendations are in response
to a request by VCA Structural (VCA) via an email dated October 4, 2023. The recommendations
pertaining to retaining walls and mat foundations have been revised and supersede those provided
in the “Preliminary Geotechnical Evaluation…” by GeoTek, dated July 28, 2022. The numbering
for the retaining wall and mat foundation recommendations corresponds to that provided in the
“Preliminary Geotechnical Evaluation…” (2022).
5.3.7 Mat Slab Foundation
The mat slab foundation for the subterranean parking garage should have a minimum embedment
depth of 24 inches below lowest adjacent grade and may be designed using an allowable bearing
capacity of 4,500 psf. The recommended allowable soil bearing pressures may be increased by
one-third for temporary seismic or wind loading. Reinforcement within the mat foundation
should be determined by the structural engineer.
For resistance to lateral loads, an allowable coefficient of friction of 0.33 between the base of the
foundation elements. In addition, an allowable passive earth resistance equal to an equivalent
fluid weight of 300 pounds per cubic foot (pcf) for dense old paralic deposits or Santiago
Formation bedrock acting against the foundations may be used to resist lateral forces. The top
GeoTek, Inc.
1384 Poinsettia Avenue, Suite A Vista, CA 92081-8505
(760) 599-0509 Offic, (760) 599-0593 Fa: www.geotekusa.com
SUPPLEMENTAL GEOTECHNICAL RECOMMENDATION LETTER October 23, 2023
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 2
foot of passive resistance for foundations should be neglected unless confined by pavement or
slab.
A coefficient of friction of 0.33 may be utilized between concrete slabs and subgrade soils without
a moisture barrier, and 0.20 for slabs underlain by moisture barrier.
A modulus of subgrade reaction (k-value) of 250 pounds per cubic inch (pci) may be considered
for design.
The design of mat foundations should incorporate the vertical modulus of subgrade reaction.
This value is a unit value for a 1-foot square footing and should be reduced in accordance with
the following equation when used with the design of larger foundations. This assumes that the
bearing soil will consist of dense old paralic deposits or Santiago Formation bedrock.
Where: KS = unit subgrade modulus
KR = reduced subgrade modulus
B = foundation width (feet)
5.4 RETAINING WALL DESIGN AND CONSTRUCTION
General Design Criteria
Preliminary grading plans are not yet available. Retaining wall foundations embedded a minimum
of 18 inches into engineered fill or dense formational materials should be designed using an
allowable bearing capacity of 4,500 pounds per square foot (psf) may be used for design of
continuous and perimeter footings that meet the depth and width requirements in the table
above. This value may be increased by 300 pounds per square foot for each additional 12 inches
in depth and 200 pounds per square foot for each additional 12 inches in width to a maximum
value of 6,500 psf. Additionally, an increase of one-third may be applied when considering short-
term live loads (e.g., seismic and wind loads). Passive pressure may be computed as an equivalent
fluid having a density of 300 psf per foot of depth, to a maximum earth pressure of 4,500 psf for
footings founded on engineered fill. A coefficient of friction between soil and concrete of 0.33
may be used with dead load forces. Passive pressure and frictional resistance can be combined
without reduction.
An equivalent fluid pressure approach may be used to compute the horizontal active pressure
against the wall. The appropriate fluid unit weights are given in the table below for specific slope
gradients of retained materials.
K = K [B+ 1]2
R s 2B
5.4.1
GEOTEK
SUPPLEMENTAL GEOTECHNICAL RECOMMENDATION LETTER October 23, 2023
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 3
Surface Slope of
Retained Materials
(H:V)
Equivalent Fluid Pressure
(PCF)
Select Backfill*
Level 40
2:1 65
*Select backfill should consist of approved materials with an
EI<20 and should be provided throughout the active zone.
The above equivalent fluid weights do not include other superimposed loading conditions such
as expansive soil, vehicular traffic, structures, seismic conditions, or adverse geologic conditions.
5.4.2 Restrained Retaining Walls
Any retaining wall that will be restrained prior to placing backfill should be designed for at-rest
soil conditions using an equivalent fluid pressure of 65 pcf (select backfill), plus any applicable
surcharge loading.
5.4.3 Seismic Earth Pressures on Retaining Walls
As required by the 2019 CBC, walls with a retained height greater than six feet are required to
include an incremental seismic earth pressure in the wall design. Based upon review, walls with
retained heights of up to approximately 15 feet are planned at the site.
The lateral pressure on retaining walls due to earthquake motions (dynamic lateral force) should
be calculated as PA = 3/8H2kh where
PA = dynamic lateral force (pounds-per-foot)
= unit weight = 127-pounds-per-cubic-foot
H = height of wall (feet)
kh = seismic coefficient = 0.187
The dynamic lateral force may also be expressed as 18-pounds-per-cubic-foot EFP.
The dynamic lateral force is in addition to the static force and should be applied as an inverted
triangular distribution, with the resultant applied at a height of 2/3H above the base of the wall.
The dynamic lateral force need not be applied to retaining walls 6-feet or less in height.
Restrained retaining walls may be designed for at-rest loading condition or the active and seismic
loading condition combined. Typically, it appears the design of the restrained at-rest condition
for retaining wall loading may be adequate for the seismic design of the retaining walls. However,
GEOTEK
SUPPLEMENTAL GEOTECHNICAL RECOMMENDATION LETTER October 23, 2023
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 4
the active earth pressure combined with the seismic design load should be reviewed and also
considered in the design of the retaining walls.
5.4.4 Hydrostatic Conditions
Retaining walls experiencing hydrostatic conditions free to rotate (cantilevered walls) should be
designed for an active pressure of 80-pounds-per-cubic-foot equivalent fluid pressure (EFP).
Retaining walls experiencing hydrostatic conditions restrained from movement at the top should
be designed for an at-rest pressure of 90-pounds-per-cubic-foot EFP.
5.4.5 Wall Backfill and Drainage
Wall backfill should include a minimum one (1) foot wide section of ¾ to 1-inch clean crushed
rock (or approved equivalent). The rock should be placed immediately adjacent to the back of
wall and extend up from the backdrain to within approximately 12 inches of finish grade. The
upper 12 inches should consist of compacted onsite materials. If the walls are designed using the
“select” backfill design parameters, then the “select” materials shall be placed within the active
zone as defined by a 1:1 (H:V) projection from the back of the retaining wall footing up to the
retained surface behind the wall. Presence of other materials might necessitate revision to the
parameters provided and modification of wall designs.
The backfill materials should be placed in lifts no greater than 8-inches in thickness and compacted
to a minimum of 90% of the maximum dry density as determined in accordance with ASTM Test
Method D 1557. Proper surface drainage needs to be provided and maintained. Water should
not be allowed to pond behind retaining walls. Waterproofing of site walls should be performed
where moisture migration through the wall is undesirable.
Retaining walls should be provided with an adequate pipe and gravel back drain system to reduce
the potential for hydrostatic pressures to develop. A 4-inch diameter perforated collector pipe
(Schedule 40 PVC, or approved equivalent) in a minimum of one (1) cubic foot per lineal foot of
3/8 to one (1) inch clean crushed rock or equivalent, wrapped in filter fabric should be placed
near the bottom of the backfill and be directed (via a solid outlet pipe) to an appropriate disposal
area.
As an alternative to the drain, rock and fabric, a pre-manufactured wall drainage product
(example: Mira Drain 6000 or approved equivalent) may be used behind the retaining wall. The
wall drainage product should extend from the base of the wall to within two (2) feet of the
ground surface. The subdrain should be placed in direct contact with the wall drainage product.
GEOTEK
SUPPLEMENTAL GEOTECHNICAL RECOMMENDATION LETTER October 23, 2023
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 5
Drain outlets should be maintained over the life of the project and should not be
obstructed or plugged by adjacent improvements.
CLOSURE
Since GeoTek’s recommendations are based on the site conditions observed and encountered,
and laboratory testing, GeoTek’s conclusions and recommendations are professional opinions
that are limited to the extent of the available data. Observations during construction are
important to allow for any change in recommendations found to be warranted. These opinions
have been derived in accordance with current standards of practice and no warranty is expressed
or implied. Standards of practice are subject to change with time.
Should you have any questions after reviewing this supplementary letter, please feel free to
contact our office at your convenience.
Respectfully submitted,
GeoTek, Inc.
Christopher D. Livesey
CEG, 2733 Exp. 05/31/23
Vice President
Edwin R. Cunningham
RCE 81687, Exp. 03/31/24
Project Engineer
GEOTEK
SUPPLEMENTAL GEOTECHNICAL RECOMMENDATION LETTER October 23, 2023
Wermers Companies Project No. 3780-SD
Proposed Hope Apartments, Carlsbad, California 92008 Page 6
REFERENCES
GeoTek, Inc. 2022, “Preliminary Geotechnical Evaluation, Proposed Hope Apartments, Carlsbad,
California,” Project No. 3780-SD, dated July 28, 2022.
, 2023, “Supplemental Infiltration Recommendation Letter, APN 203-320-20, -02, -48, -51,
40, and -41, Carlsbad Village Drive and Hope Avenue, Carlsbad, California 92008,” PN
3780-SD, dated January 23, 2023.
, 2023, “Revised Supplemental Infiltration Recommendation Letter and Response to City
Review Comments, APN 203-320-20, -02, -48, -51, 40, and -41, Carlsbad Village Drive
and Hope Avenue, Carlsbad, California 92008,” PN 3780-SD, dated March 22, 2023,
revised May 11, 2023.
GEOTEK