HomeMy WebLinkAboutCDP 2025-0021; GOTZ RESIDENCE; PRELIMINARY GEOTECHNICAL INVESTIGATION; 2025-02-03
PRELIMINARY GEOTECHNICAL INVESTIGATION AND RECOMMENDATIONS
PROPOSED NEW RESIDENCE
TO BE LOCATED AT 3451 GARFIELD STREET, CARLSBAD, CALIFORNIA
EDG Project No. 247114-1
February 3, 2025
PREPARED FOR:
Spaces Renewed
1107 South Coast Hwy
Oceanside, California
Date: February 3, 2025
To: Spaces Renewed
Attn: Marshall Booth
1107 South Coast Hwy
Oceanside, California 92054
Re: Proposed new residence, to be located at 3451 Garfield Street, Carlsbad California.
Subject: Geotechnical Investigation and Recommendations Report
In accordance with your request and our signed proposal we have provided this preliminary geotechnical
investigation and recommendations report of the subject site for the proposed new residence, and
associated hardscape & landscape improvements.
The findings of the investigation, earthwork recommendations and foundation design parameters are
presented in this report. In general, it is our opinion that the proposed construction, as described herein,
is feasible from a geotechnical standpoint, provided the recommendations of this report and generally
accepted construction practices are followed.
If you have any questions regarding the following report, please do not hesitate to contact our office.
Sincerely,
ENGINEERING DESIGN GROUP
Steven Norris
California GE#2590, CEG#2263
Table of Contents
1.0 SCOPE ................................................................................................................................................ 1
2.0 SITE AND PROJECT DESCRIPTION ...................................................................................................... 1
3.0 FIELD INVESTIGATION ....................................................................................................................... 1
4.0 SUBSURFACE CONDITIONS ............................................................................................................... 1
5.0 GEOLOGY ........................................................................................................................................... 2
6.0 GEOLOGIC HAZARDS ......................................................................................................................... 3
7.0 GROUND WATER ............................................................................................................................... 4
8.0 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS ................................................................ 4
9.0 GRADING AND EARTHWORK............................................................................................................. 6
10.0 SEISMIC DESIGN PARAMETERS ......................................................................................................... 7
11.0 SHALLOW FOUNDATIONS ................................................................................................................. 8
12.0 SOIL CORROSIVITY AND VAPOR EMISSION ...................................................................................... 9
13.0 CONCRETE SLAB-ON-GRADE ........................................................................................................... 11
14.0 RETAINING WALLS........................................................................................................................... 12
15.0 FLEXIBLE PAVEMENT DESIGN .......................................................................................................... 14
16.0 INFILTRATION .................................................................................................................................. 14
17.0 SURFACE DRAINAGE ........................................................................................................................ 15
18.0 LABORATORY TESTING .................................................................................................................... 16
19.0 CONSTRUCTION OBSERVATION AND TESTING ............................................................................... 16
20.0 MISCELLANEOUS ............................................................................................................................. 17
FIGURES
Site Vicinity Map .......................................................................................................................... Figure No. 1
Site Location Map ........................................................................................................................ Figure No. 2
Site Plan ....................................................................................................................................... Figure No. 3
Test Boring Logs ........................................................................................................... Test Boring Logs 1 – 2
Test Pit Logs ............................................................................................................................. Test Pit Logs 1
Geo Map & Cross Section ...................................................................................... Geo Map & Cross Section
APPENDICES
References .................................................................................................................................... Appendix A
General Earthwork and Grading Specifications ............................................................................ Appendix B
Laboratory Results ........................................................................................................................ Appendix C
Retaining Wall Drainage................................................................................................................Appendix D
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3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
1.0 SCOPE
This report gives our geotechnical recommendations for the proposed new residence, to be located at
3451 Garfield Street, Carlsbad, California (See Figure No. 1, "Site Vicinity Map", and Figure No. 2, "Site
Location Map"). We understand the scope of work includes 1) the demolition of existing improvements,
2) construction of new residence, 3) hardscape & landscape improvements. The scope of our work
conducted onsite to date has included a visual reconnaissance of the property and surrounding areas,
review of geologic maps, review of historical aerial photos, a limited subsurface investigation of the
subject property, collection of samples for laboratory testing, review of preliminary architectural plans,
and preparation of this report presenting our findings, conclusions, and recommendations.
2.0 SITE AND PROJECT DESCRIPTION
The subject property is located at 3451 Garfield Street, in the city of Carlsbad, California. For the purposes
of this report the lot is assumed to face east. The property is a corner lot, bordered to the north and west,
by similarly developed, single-family homes, to the south by Maple Avenue, and to the east by Garfield
Street.
The site area topography generally consists of coastal foothill terrain. At the time of this report the lot is
developed with a single-story, single-family residence, detached garage, and associated
hardscape/landscape improvements. The building pad is generally flat, with an elevation differential of
approximately 4 feet across the site.
Based upon our review of the preliminary project plans, we understand the proposed development will
consist of the demolition of existing improvements, the construction of a new residence, and associated
hardscape/landscape improvements.
3.0 FIELD INVESTIGATION
Our field investigation of the property consisted of a site reconnaissance, site field measurements,
observation of existing conditions on-site and on adjacent sites and a limited subsurface investigation of
soil conditions. Our subsurface investigation consisted of the visual observation of 2 exploratory test
borings, and one test pit, in the general areas of proposed construction. The approximate locations of the
exploratory test excavations are given in Figure No. 3, "Site and Approximate Location of Test Borings".
4.0 SUBSURFACE CONDITIONS
Our subsurface investigation consisted of the excavation of two exploratory test borings, one hand dug
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ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
test pit, the visual observation and logging of soil types encountered, soil measurements with standard
penetrometer, and the sampling of soil profiles for laboratory testing. Laboratory testing included testing
for sulfate content/corrosivity, shear, and expansion index. Fill and weathered profiles were encountered
to approximate depths of 4 feet below adjacent grade in our exploratory test borings. Soil types
encountered within our exploratory test borings, are described as follows:
4.1 Fill / Weathered / Unsuitable
Fill/topsoil materials were encountered to depths of 4 feet below adjacent grade in our exploratory test
borings and test pit. These materials consist of light brown to reddish brown, dry to slightly moist, silty
sand and sandy silt. These materials are not considered suitable for the support of structures and
structural improvements in their present state but may be utilized as recompacted fill, provided the
recommendations of this report are followed. Unsuitable soil materials classify as SW – SM per the
Unified Soil Classification System, and based on laboratory results, possess a very low potential for
expansion.
4.2 Qop6-7 – Old Paralic Deposits - Undivided, Late to Middle Pleistocene (as mapped per Tan S.S.,
Kennedy, M.P., et.al., 1996).
Paralic Deposits were found to underlie the fill/topsoil material within exploratory test borings. Paralic
Deposit material consists of reddish brown to brown, to light brown, moist, medium dense, silty sand and
sandy silt. These materials are considered suitable for the support of structures and structural
improvements, provided the recommendations of this report are followed. Paralic Deposit materials
classify as SW to SM per the Unified Soil Classification System, and based upon our experience and
observation, are considered to possess a low potential for expansion.
Detailed logs of our exploratory test borings, as well as a depiction of their locations, please see the Figures
section attached herein.
5.0 GEOLOGY
The project site is located within the Peninsular Ranges Geomorphic Province of California. The Peninsular
Ranges extend 125 miles from the Transverse Ranges and the Los Angeles Basin south to the Mexican
Border and beyond. This Geomorphic province is bounded to the east by the Colorado Desert and the Gulf
of California. The topography of the area in and around the subject site consists of coastal foothill terrain
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ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
and relatively shallow drainages. The project site is overlain by fill/topsoil profiles and underlain by Middle
Pleistocene age Paralic Deposits.
6.0 GEOLOGIC HAZARDS
6.1 FAULTS
The nearest mapped active fault (Holocene) is the Rose Canyon Fault (Newport-Inglewood Fault zone) in
the Offshore Zone of Deformation, located approximately 2 miles west of the subject site. Other major
mapped faults in the region are the Elsinore Fault and associated faults within the Elsinore zone and the
San Jacinto Fault and related branches within the San Jacinto zone. The subject site is located
approximately 47 miles southwest from the San Jacinto Fault zone and approximately 25 miles southwest
of the Elsinore Fault zone.
Our review of geologic literature pertaining to the general site area indicates the subject site is not within
a mapped Alquist-Priolo fault zone. It is our opinion that the site could be subjected to moderate to severe
ground shaking in the event of a major earthquake along any of the faults in the Southern California
region. The seismic risk at this site is similar to that of the surrounding developed area.
6.2 LIQUEFACTION, LATERAL SETTLEMENT, SUBSIDENCE
Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. Research
and historical data indicate that loose, granular soils underlain by a near-surface ground water table are
most susceptible to liquefaction, while the stability of most silty sands and clays is not adversely affected
by vibratory motion. Because of the dense nature of the bedrock materials underlying the site and the
lack of near surface water, the potential for lateral spreading, liquefaction, subsidence or seismically
induced dynamic settlement at the site is considered low. The effects of seismic shaking can be reduced
by adhering to the most recent edition of the California Building Code and current design parameters of
the Structural Engineers Association of California.
6.3 TSUNAMI
Tsunami are sea waves generated by submarine earthquakes, landslides, or volcanic activity. Submarine
earthquakes are common along the edge of the Pacific Ocean and coastal areas are subject to potential
inundation by tsunami. Most of the tsunamis recorded on the San Diego Bay tidal gauge have only been
a few tenths of a meter in height. The possibility of a destructive tsunami along the San Diego coastline is
considered low. Tsunami or storm waves (associated with winter storms), even in conjunction with high
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ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
tides, do not have the potential for inundations of the subject site.
6.4 SLOPE STABILITY
As part of the preparation of this report we have reviewed geologic maps of the subject area. Our review
of geologic maps does not indicate landslide deposits at the area in and around the subject site. We do
not anticipate new slopes as part of proposed development.
7.0 GROUND WATER
Static ground water was not encountered within the depth of our excavations on site. Perched
groundwater conditions can develop during periods of wet weather and/or can develop over time, where
no such condition previously existed. Perched groundwater conditions should be considered/accounted
for as part of the project design.
Based upon a review of provided project information, we understand proposed new structures will be
configured so as to lie above surrounding site grade and will not include subterranean building areas. For
structures built without subterranean building areas we recommend a properly detailed vapor barrier be
incorporated into the building. The vapor barrier should be designed by the project architect and/or
waterproofing consultant. If groundwater conditions are encountered during site excavations, a slab
underdrain system may be required. Trenches below slab should be detailed with perimeter and trench
cut-off walls keyed into competent material. Please see our INFILTRATION and DRAINAGE sections for
additional recommendations.
8.0 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS
Based upon our review of preliminary project plans, we understand the proposed improvements will
include the construction of a new residence, with associated hardscape & landscape improvements. In
general, it is our opinion that the proposed new structures and improvements, as discussed and described
herein, are feasible from a geotechnical standpoint, provided the recommendations of this report and all
applicable codes are followed.
• Based upon our subsurface investigation competent material is anticipated at approximate
depths of 4 feet below existing grades in the areas of proposed improvement. The depth to
competent material should be confirmed during site grading by a representative of Engineering
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ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
Design Group.
• We anticipate shallow foundations and slab-on-grade floors are proposed for the new structures.
• Due to the depth to competent material encountered in our test locations, we offer two options
for foundations.
OPTION 1:
Under option 1, we anticipate the removal and re-compaction of the upper 4 feet of unsuitable
material. Building footings and slabs will be founded on competent, non-expansive, recompacted
materials.
OPTION 2:
Under option two, we anticipate structural slabs, and deepened foundations in combination with
concrete slurry. Excavations for new footings shall extend a minimum of 1-foot into competent
materials.
Concrete slurry mix may be added up to a depth of 36 inches as measured from below existing
grade to top of concrete slurry mix. Depth to top of concrete slurry mix shall not exceed depth to
bottom of designed footing.
Unreinforced cement slurry to consist of a minimum 30-inch wide, 2000 psi pea gravel slurry
extending a minimum 1 foot into competent material.
Structural slabs shall be designed to span unsuitable material in the areas of new slab-on-grade
floors.
• Under both options, depth to competent material, to be verified in the field by a representative
of this office during construction operations.
• Based upon our review of the preliminary plans, we anticipate adjacent property and
improvements will not be negatively impacted from a geotechnical standpoint, provided the
recommendations of this report, generally accepted construction practices, applicable codes,
OSHA requirements, civil design elements are implemented and all applicable city and/or county
standards are followed.
• Any changes in the proposed design should be reviewed by this office for any revisions to the
recommendations herein.
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3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
9.0 GRADING AND EARTHWORK
All grading shall be done in accordance with the recommendations below as well as Appendix B of this
report and the standards of county and state agencies, as applicable.
9.1 Site Preparation
Prior to any grading, the areas of proposed improvements should be cleared of surface and subsurface
debris (including organic topsoil, vegetative and construction debris). Removed debris should be properly
disposed of off-site prior to the commencement of any fill operations. Construction debris should not
generally be mixed with fill soils. Holes resulting from the removal of debris, existing structures, or other
improvements, should be filled, and compacted.
9.2 Removals
In areas of proposed structures, fill/weathered profiles found to mantle the site, are not suitable for the
structural support of buildings or structural improvements in their present state. Under Option 1, we
anticipate the removal of all unsuitable materials as part of site grading operations for the creation of
the building pads. Under Option 2, removals will be limited to the excavation of footings.
9.3 Transitions
All settlement sensitive improvements (including but not limited to new structures, etc.), should be
constructed on a uniform building pad. Under Option 1, we anticipate all new footings to be placed in
competent re-compacted materials. No transitions are anticipated. Under Option 2, we anticipate all new
footings to be founded into competent formational materials. No transitions are anticipated.
9.4 Fills/Backfill
All fill/backfill material should be cleaned of loose debris and oversize material (material more than 6
inches in diameter), be brought to approximately +2% of optimum moisture content and re-compacted
to at least 90 percent relative compaction (based on ASTM D1557 – latest edition). Fills should generally
be placed in lifts not exceeding 6 - 8 inches in thickness. All fill/backfill requires testing for relative density
every 2 vertical feet at a minimum. Utility trenches should be properly backfilled in accordance with the
latest edition of Green Book standards.
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3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
9.5 Slopes
Although not anticipated, where new slopes are constructed, permanent slopes may be cut to a face ratio
of 2:1 (horizontal to vertical). Permanent fill slopes shall be placed at a maximum 2:1 slope face ratio. All
temporary cut slopes shall be excavated in accordance with OSHA requirements for Type B soil types and
OSHA Alternative Sloping Plans and shall not undermine adjacent properties, public improvements, or any
structures without proper shoring of excavation and/or structures. Subsequent to grading, planting or
other acceptable cover should be provided to increase the stability of slopes, especially during the rainy
season (October through April). See removal section for additional slope recommendations.
9.6 Driveways and Flatwork
In the areas of proposed driveways and exterior flatwork we recommend, the upper 12 inches of subgrade
shall be ripped a minimum of 12 inches, moisture conditioned to near optimum moisture content and
compacted to 90% minimum relative compaction (ASTM D1557 – latest edition).
(Please see our CONCRETE SLAB-ON-GRADE section for additional flatwork recommendations, and our
INFILTRATION section for additional paver recommendations).
10.0 SEISMIC DESIGN PARAMETERS
10.1 Seismic Design Parameters, as outlined in the table below.
Site Class D*
Seismic Design Category D*
ASCE 7-16 Seismic Design Parameters
SS (g) 1.097
S1 (g) 0.396
SMS (g) 1.316
SDS (g) 0.878
ASCE 7-16 Acceleration Parameters
PGA = MCEG peak ground acceleration 0.485
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3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
PGAM = Site modified peak ground acceleration 0.582
*Using code values provided in the table above rather than performing a
ground motion hazard analysis, requires the exception identified in ASCE
Section 11.4.8 be utilized in structural design.
11.0 SHALLOW FOUNDATIONS
The following design parameters may be utilized for new foundations founded on competent material.
11.1 Footings bearing uniformly in competent material may be designed utilizing maximum allowable
soils pressure of 2,000 psf.
11.2 Bearing values may be increased by 33% when considering wind, seismic, or other short duration
loadings.
11.3 The parameters in the table below should be used as a minimum for designing new footing width
and depth below lowest adjacent grade into competent material. Footing depths are to be
confirmed in the field by a representative of Engineering Design Group prior to the placement of
form boards, steel, and removal of excavation equipment.
No. of Floors
Supported Minimum Footing Width *Minimum Footing Depth Below
Lowest Adjacent Grade
1 15 inches 18 inches
2 15 inches 18 inches
*Footings are anticipated to be founded in competent material, deepened at limited
locations as determined by representative of EDG during footing excavation operations.
11.4 All footings founded into competent material should be reinforced with a minimum of two #4
bars at the top and two #4 bars at the bottom (3 inches above the ground). Footing reinforcing
steel should be designed by the project structural engineer and account for site-specific loading
conditions and minimum steel requirements. In areas where the footing depth is in excess of 30
inches, special footing detailing and/or a stemwall system designed by the project structural
engineer will be necessary.
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3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
11.5 All isolated spread footings should be designed utilizing the above given bearing values and
footing depths and be reinforced with a minimum of #4 bars at 12 inches o.c. in each direction (3
inches above the ground). Isolated spread footings should have a minimum width and depth of
24 inches.
11.6 The maximum expected total static settlement for the proposed structure supported on a
conventional foundation system utilizing a maximum allowable soil bearing pressure of 2,000 psf
(deriving support in competent material), is estimated to be on the order of ½ to 1 inch.
Differential settlement is not expected to exceed ½ inch over a distance of twenty (20) feet.
11.7 For footings adjacent to slopes a minimum of 10 feet horizontal setback in competent material or
properly compacted fill should be maintained. A setback measurement should be taken at the
horizontal distance from the bottom of the footing to slope daylight. Where this condition cannot
be met, it should be brought to the attention of the Engineering Design Group for review.
11.8 All excavations should be performed in general accordance with the contents of this report,
applicable codes, OSHA requirements and applicable city and/or county standards.
11.9 All foundation subgrade soils and footings shall be pre-moistened to 2% over optimum to a
minimum of 18 inches in depth prior to the pouring of concrete.
12.0 SOIL CORROSIVITY AND VAPOR EMISSION
12.1 Resistivity and chloride testing of onsite samples from our subsurface investigation was
conducted to evaluate corrosion potential to proposed improvements. Tests performed indicate
that soils classify, according to ACI 318 standard, as category C1, and based upon laboratory
results are considered mild to moderately corrosive to buried metals. Test results are included in
Appendix C of this report. The project structural engineer to note increased concrete protection
requirements for corrosive environments, as applicable.
12.2 Laboratory testing of onsite samples for water soluble sulfates indicate soils classify, according to
ACI 318 standard, as category S0, mildly to moderately corrosive due to sulfate attack to concrete
structures.
12.3 In consideration of laboratory results and ACI standards, we recommend for moisture sensitive
slabs, retaining walls and foundations (i.e., below grade walls/spaces, built interior environments,
floor finishes) concrete with a maximum water to cement ratio of 0.45 resulting in a compressive
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ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
strength of 4,500 psi minimum (no special inspection required for water to cement ratio purposes,
unless otherwise specified by structural engineer).
12.4 For non-moisture sensitive areas, we recommend concrete with a minimum compressive strength
of 2,500 psi.
12.5 Buried metals shall be protected, and a corrosion engineer should be consulted for appropriate
mitigation recommendations. EDG is not an expert in corrosion protection. Design
recommendations for the protection of improvements from corrosive environment shall be
provided by the corrosion consultant.
12.6 Where onsite improvements propose the use of reclaimed water, onsite soils are to be considered
highly corrosive to buried metals. Precautions should be taken to protect all buried metals.
12.7 Slab Underlayment: We recommend the following beneath proposed slab-on-grade floors.
12.7.a. For moisture-sensitive areas, we recommend a vapor barrier.
12.7.b. The slab underlayment for moisture-sensitive areas consists of a vapor barrier layer (15
mil) placed below the upper one-inch of sand. The vapor barrier shall meet the following
minimum requirements: Permeance of less than 0.01 perm [grains/(ft²hr in/Hg)] as tested
in accordance with ASTM E 1745 Section 7.1 and strength per ASTM 1745 Class A.
12.7.c. In areas of level slab on grade floors, we recommend a one-inch layer of coarse sand
material, Sand Equivalent (S.E.) greater than 50 and washed clean of fine materials,
should be placed beneath the slab in moisture-sensitive areas, above the vapor barrier.
There shall be not greater than a 2-inch difference across the sand layer.
12.7.d. The vapor barrier should extend down the interior edge of the footing excavations a
minimum of 6 inches. The vapor barrier should lap a minimum of 8 inches, sealed along
all laps with the manufacturer’s recommended adhesive. Beneath the vapor barrier a
uniform layer of 4 inches of clean ½ inch gravel (2022 California Greenbook Section
4.505.2.1) is recommended under the slab in order to more uniformly support the slab,
help distribute loads to the soils beneath the slab, and act as a capillary break.
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3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
12.8 The project waterproofing consultant should provide all slab underdrain, slab sealers and various
other details, specifications, and recommendations (i.e., Moiststop and Linkseal) at areas of
potential moisture intrusion. Engineering Design Group accepts no responsibility for design or
quality control of waterproofing elements of the building.
13.0 CONCRETE SLAB-ON-GRADE
We anticipate new, concrete slab-on-grade floors will be placed on competent, re-compacted material,
or designed as structural slabs to span unsuitable materials. Where new, concrete slab-on-grade floors,
and exterior improvements are proposed, we recommend the following as the minimum design
parameters.
13.1 Interior concrete slab-on-grade: Minimum thickness of 5 inches and reinforced with #4 bars at
18 inches o.c. placed at the midpoint of the slab.
Concrete driveways: Minimum thickness of 5 inches and reinforced with #4 bars at 18 inches o.c.
placed at the midpoint of the slab.
Exterior flatwork / Parking areas: Minimum thickness of 4 inches and reinforced with #3 bars at
16 inches o.c. at the midpoint of the slab.
13.1.a. Slump: Between 3 and 4 inches maximum.
13.1.b. Aggregate Size: ¾ - 1 inch.
13.2 Adequate control joints should be installed to control the unavoidable cracking of concrete that
takes place when undergoing its natural shrinkage during curing. The control joints should be well
located to direct unavoidable slab cracking to areas that are desirable by the designer.
13.3 All required fills used to support slabs, should be placed in accordance with the GRADING AND
EARTHWORK section of this report and the attached Appendix B, and compacted to 90 percent
relative compaction (Modified Proctor Density, ASTM D-1557 – Latest Edition).
13.4 Concrete should be poured during cool (40 – 65 degrees) weather if possible. If concrete is poured
in hotter weather, a set retarding additive should be included in the mix, and the slump kept to a
minimum.
13.5 All subgrade soils to receive concrete slabs and flatwork are to be pre-soaked to 2 percent over
optimum moisture content, to a minimum depth of 18 inches.
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ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
13.6 Exterior concrete flatwork, due to the nature of concrete hydration and minor subgrade soil
movement, are subject to normal minor concrete cracking. To minimize expected concrete
cracking, the following additional recommendations should be implemented:
13.6.a. Exterior concrete flatwork should be poured with a 10-inch-deep thickened edge.
Flatwork adjacent to top of a slope should be constructed with an outside footing to attain
a minimum of 7 feet distance to daylight.
13.6.b. Exterior concrete flatwork should be constructed with tooled joints creating concrete
sections no larger than 225 square feet. For sidewalks, the maximum run between joints
should not exceed 5 feet. For rectangular shapes of concrete, the ratio of length to width
should generally not exceed 0.6 (i.e., 5 ft. long by 3 ft. wide). Joints should be cut at
expected points of concrete shrinkage (such as male corners), with diagonal
reinforcement placed in accordance with industry standards.
13.6.c. Isolation joints should be installed at exterior concrete where exterior concrete is poured
adjacent to existing foundations.
13.6.d. Drainage adjacent to exterior concrete flatwork should direct water away from the
improvements. Concrete subgrade should be sloped and directed to the collective
subdrain system, such that water is not trapped below the flatwork.
13.7 The recommendations set forth herein are intended to reduce cosmetic nuisance cracking. The
project concrete contractor is ultimately responsible for concrete quality and performance and
should pursue a cost-benefit analysis of these recommendations, and other options available in
the industry, prior to the pouring of concrete.
14.0 RETAINING WALLS
New retaining walls up to 6 feet may be designed and constructed in accordance with the following
recommendations and minimum design parameters.
14.1 Retaining wall footings should be designed in accordance with the allowable bearing criteria given
in the Foundations section of this report and should maintain minimum footing depths outlined
in the Foundations section of this report. Any retaining wall footings are to be placed on
competent material. Where cut-fill transitions may occur, alternative detailing may be provided
by the Engineering Design Group on a case-by-case basis.
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3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
14.2 Unrestrained cantilever retaining walls should be designed using an active equivalent fluid
pressure of 35 pcf. This assumes that granular, free draining material with low potential for
expansion (E.I. <20) will be used for backfilling, and that the backfill surface will be level. Where
soil with potential for expansion is not low (E.I. > 20) a new active fluid pressure will be provided
by the project soils engineer. Backfill materials should be considered prior to the design of the
retaining walls to ensure accurate detailing. We anticipate onsite material may not be utilized as
retaining wall backfill. Additional Expansion Index Testing may be conducted during site grading
to confirm suitability.
14.3 Where the backfill behind the wall is sloped at a maximum slope of 2:1 (H:V) an active equivalent
fluid pressure of 55 pcf, shall be utilized.
14.4 Any other surcharge loadings shall be analyzed in addition to the above values. These surcharge
loads shall include foundations, construction equipment, vehicular traffic, etc.
14.5 If the tops of retaining walls are restrained from movement, they should be designed for a uniform
at-rest soil pressure of 60 psf.
14.6 Retaining walls shall be designed for additional lateral forces due to earthquake, where required
by code, utilizing the following design parameters.
14.6.a. For unrestrained, retaining walls with level backfill, we recommend an additional seismic
load of 15H applied as a uniform load. The resultant load should be applied a distance of
0.5H from the bottom of the footing.
14.6.b. For unrestrained, retaining walls with sloped backfill up to 2:1 slope, we recommend an
additional seismic load of 18H applied as a uniform load. The resultant load should be
applied a distance of 0.5H from the bottom of the footing.
14.6.c. The unit weight of 125 pcf for the onsite soils may be utilized.
14.7 The above design parameters assume unsaturated conditions. Retaining wall designs for sites with
a hydrostatic pressure influence (i.e., groundwater within depth of retaining wall or waterfront
conditions) will require special design considerations and should be brought to the attention of
Engineering Design Group.
Spaces Renewed – Gotz Residence Page No. 14
3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
14.8 Passive soil resistance may be calculated using an equivalent fluid pressure of 300 pcf. This value
assumes that the soil being utilized to resist passive pressures extends horizontally 2.5 times the
height of the passive pressure wedge of the soil. Where the horizontal distance of the available
passive pressure wedge is less than 2.5 times the height of the soil, the passive pressure value
must be reduced by the percent reduction in available horizontal length.
14.9 A coefficient of friction of 0.32 between the soil and concrete footings may be utilized to resist
lateral loads in addition to the passive earth pressures above.
14.10 All walls shall be provided with adequate back drainage to relieve hydrostatic pressure, and be
designed in accordance with the minimum standards contained in the "Retaining Wall Drainage
Detail", Appendix D. The waterproofing elements shown on our details are minimums and are
intended to be supplemented by the waterproofing consultant and/or architect. The
recommendations should be reviewed in consideration of proposed finishes and usage,
performance expectations and budget.
14.11 If deemed necessary by the project owner, based on the above analysis, waterproofing systems
can be upgraded to include slab under drains and enhanced waterproofing elements.
14.12 In moisture sensitive areas (i.e., interior living space where vapor emission is a concern), in our
experience poured-in-place concrete provides a surface with higher performance-repairability of
below grade waterproofing systems. The developer should consider the cost-benefit of utilizing
cast in place building retaining walls in lieu of masonry as part of the overall construction of the
commercial structure. Waterproofing at any basement floors is recommended in areas of
moisture sensitive floor finishes.
15.0 FLEXIBLE PAVEMENT DESIGN
At the time of this report, no new flexible pavement parking areas are proposed as part of the anticipated
development. If new flexible pavement areas are proposed, as part of a future scope change, Engineering
Design Group shall provide design recommendations.
16.0 INFILTRATION
Our review of preliminary plans indicates bioretention/infiltration facilities are likely to be proposed for
this project. Should bioretention facilities be proposed, bioretention/infiltration facilities shall be
designed to maintain sufficient horizontal and vertical offset to the future structures so as not to create a
Spaces Renewed – Gotz Residence Page No. 15
3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
groundwater condition. Infiltration facilities proposed within a 10-foot horizontal distance to a moisture
sensitive structure should be lined with an impervious barrier, within the 10-foot zone.
Based upon our review of preliminary plans, permeable pavers are proposed on the project site. In
general, where pervious pavers are included in project plans, permeable paver subgrade adjacent to the
building, shall be sloped away at 2% should be lined with an impervious liner a minimum horizontal
distance of 10 feet from building. Permeable paver subgrade shall be sloped 2% minimum to a perforated
subdrain, gravel filled (1cf/ft), wrapped in a filter fabric, permeable pavers shall be detailed with
reinforced concrete edge restraints that extend minimum 4 inches below reservoir depth, and horizontal
restraints.
In addition to the above details, specific paver detailing should be detailed and constructed per the
minimum recommendations of the specific paver manufacturer as well as the Interlocking Concrete Paver
Institute including minimum bedding specifications, base and subgrade requirements, installation
tolerances, and drainage, etc. Where runoff and storm water are directed over permeable pavements and
water is anticipated to flow through pavers into an aggregate base near and adjacent to foundations,
basements or other structures, additional detailing shall include systems to control and to prevent
subsurface flow beneath the building. Generally, these systems, detailed as part of the specific building
construction plans, may include the cut-off walls and underdrains.
Proper surface drainage and irrigation practices will play a significant role in the future performance of
the project. Please note in the Corrosion and Vapor Emission section of this report, specific
recommendations regarding water to cement ratio for moisture sensitive areas should be adhered to. The
project architect and/or waterproofing consultant shall specifically address waterproofing details.
17.0 SURFACE DRAINAGE
Adequate drainage precautions at this site are imperative and will play a critical role in the future
performance of the proposed improvements. Under no circumstances should water be allowed to pond
against or adjacent to tops of slopes and/or foundation walls.
The ground surface surrounding proposed improvements should be relatively impervious in nature, and
slope to drain away from the structure in all directions, with a minimum slope of 2% for a horizontal
distance of 10 feet (where possible). Area drains or surface swales should then be provided in low spots
to accommodate runoff and avoid any ponding of water. Any french drains, backdrains and/or slab
underdrains shall not be tied to surface area drain systems. Roof gutters and downspouts shall be installed
Spaces Renewed – Gotz Residence Page No. 16
3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
on the new and existing structures and tightlined to the area drain system. All drains should be kept clean
and unclogged, including gutters and downspouts. Area drains should be kept free of debris to allow for
proper drainage.
Overwatering can adversely affect site improvements and cause perched groundwater conditions.
Irrigation should be limited to only the amount necessary to sustain plant life. Low flow irrigation devices
as well as automatic rain shut-off devices should be installed to reduce overwatering. Irrigation practices
and maintenance of irrigation and drainage systems are an important component to the performance of
onsite improvements.
During periods of heavy rain, the performance of all drainage systems should be inspected. Problems
such as gullying, or ponding should be corrected as soon as possible. Any leakage from sources such as
water lines should also be repaired as soon as possible. In addition, irrigation of planter areas, lawns, or
other vegetation, located adjacent to the foundation or exterior flat work improvements should be strictly
controlled or avoided.
18.0 LABORATORY TESTING
Laboratory tests were performed on samples of onsite material collected during our subsurface
investigation. Test results are attached as Appendix C.
19.0 CONSTRUCTION OBSERVATION AND TESTING
The recommendations provided in this report are based on subsurface conditions disclosed by the
investigation and our general experience in the project area. Interpolated subsurface conditions should
be verified in the field during construction. The following items shall be conducted prior/during
construction by a representative of Engineering Design Group in order to verify compliance with the
geotechnical and civil engineering recommendations provided herein, as applicable. The project
structural and geotechnical engineers may upgrade any condition as deemed necessary during the
development of the proposed improvement(s).
19.1 Review of final approved grading and structural plans prior to the start of work for compliance
with geotechnical recommendations.
19.2 Attendance of a pre-grade/construction meeting prior to the start of work.
19.3 Observation of keyways, subgrade, temporary excavations, and excavation bottoms.
19.4 Testing of any fill placed, including retaining wall backfill and utility trenches.
Spaces Renewed – Gotz Residence Page No. 17
3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
19.5 Observation of retaining wall backdrain and subdrain (if applicable).
19.6 Observation of footing excavations prior to steel placement and removal of excavation
equipment.
19.7 Field observation of any "field change" condition involving soils.
19.8 Onsite inspection of final drainage detailing prior to final approval.
The project soils engineer may at their discretion deepen footings or locally recommend additional steel
reinforcement to upgrade any condition as deemed necessary during site observations. Engineering
Design Group shall, prior to the issuance of the certificate of occupancy, issue in writing that the above
inspections have been conducted by a representative of their firm, and the design considerations of the
project soils report have been met. The field inspection protocol specified herein is considered the
minimum necessary for Engineering Design Group to have exercised due diligence in the soils engineering
design aspect of this building. Engineering Design Group assumes no liability for structures constructed
utilizing this report not meeting this protocol.
Before commencement of grading, Engineering Design Group will require a separate contract for quality
control observation and testing. Engineering Design Group requires a minimum of 48 hours’ notice to
mobilize onsite for field observation and testing.
20.0 MISCELLANEOUS
It must be noted that no structure or slab should be expected to remain totally free of cracks and minor
signs of cosmetic distress. The flexible nature of wood and steel structures allows them to respond to
movements resulting from minor unavoidable settlement of fill or natural soils, the swelling of clay soils,
or the motions induced from seismic activity. All the above can induce movement that frequently results
in cosmetic cracking of brittle wall surfaces, such as stucco or interior plaster or interior brittle slab
finishes.
Data for this report was derived from surface and subsurface observations at the site and knowledge of
local conditions. The recommendations in this report are based on our experience in conjunction with the
limited soils exposed at this site. We believe that this information gives an acceptable degree of reliability
for anticipating the behavior of the proposed improvement; however, our recommendations are
professional opinions and cannot control nature, nor can they assure the soils profiles beneath or adjacent
to those observed. Therefore, no warranties of the accuracy of these recommendations, beyond the limits
Spaces Renewed – Gotz Residence Page No. 18
3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
of the obtained data, is herein expressed or implied. This report is based on the investigation at the
described site and on the specific anticipated construction as stated herein. If either of these conditions
is changed, the results would also most likely change. Man-made or natural changes in the conditions of
a property can occur over a period. In addition, changes in requirements due to state-of-the-art
knowledge and/or legislation are rapidly occurring. As a result, the findings of this report may become
invalid due to these changes. Therefore, this report for the specific site is subject to review and not
considered valid after a period of one year, or if conditions as stated above are altered.
It is the responsibility of the owner or his/her representative to ensure that the information in this report,
be incorporated into the plans and/or specifications and construction of the project. It is advisable that a
contractor familiar with construction details typically used to deal with the local subsoil and seismic
conditions be retained to build the structure. If you have any questions regarding this report, or if we can
be of further service, please do not hesitate to contact us. We hope the report provides you with necessary
information to continue with the development of the project.
FIGURES
FIGURE 1
Vicinity Map
Site Location
Project: Gotz Residence
Address: 3451 Garfield Street, Carlsbad, California
EDG Project No: 247114-1
FIGURE 2
Site Map
Site Location
Project: Gotz Residence
Address: 3451 Garfield Street, Carlsbad, California
EDG Project No: 247114-1
FIGURE 3
Site and Approximate
Location of Test Pits
Not to Scale
B1
B2
Project: Gotz Residence
Address: 3451 Garfield Street, Carlsbad, California
EDG Project No: 247114-1
TP1
(760) 839-7302
DESIGN GROUP
ENGINEERING
SAN MARCOS, CA 92069
2121 MONTIEL ROAD
FAX (760) 480-7477
ADDITIONAL NOTES / COMMENTS:
PROJECT NUMBER
PROJECT NAME
LOCATION
LOG OF BORING No.
SHEET _ OF _
B-
DATE DRILLED
DEPTH
(feet)
SAMPLE
DRILLING METHOD
AND TYPE OF RIG
TOTAL DEPTH
DRILLED (feet)
LOGGED BY BACKFILLED/CONVERTED TO WELL ON(date)APPROX SURFACE
ELEVATION (feet)
DIAMETER OF BORING GROUNDWATER
LEVEL (feet BGS)
FIRST
NONE
COMPLETION
NONE
SAMPLE
NUMBER
BLOW *
COUNTS
SPT
N **
GRAPHIC
LOG MATERIAL DESCRIPTION AND
NOTES
WATER
CONTENT
TYPE OF
SAMPLER(S)CALIFORNIA
SPT TYPE OF
HAMMER
WEIGHT (lbs)
140
DROP (in.)
30SAFTEY
25
20
15
GOTZ RESIDENCE
247114-1
3451 GARFIELD STREET, CARLSBAD, CA 92008
6"
TRIPOD RIG
2
SN/RM
1-17-2025
ELEVATION
(feet)
25
20
15
10
5
2
1
3
4
5
6
7
8
9
10
24
11
12
13
14
16
17
18
19
21
22
23
1
2
3
4
3,5
5
10
17
15
23
6,8
9
7,7
8
11,10
13
0' - 2' - DRY, LOOSE, SILTY SAND
REDDISH BROWN, SILTY MOIST, LOOSE, SILTY
SAND/SANDY SILT
REDDISH BROWN, MOIST, MEDIUM
DENSE, SILTY SAND/SANDY SILT
REDDISH BROWN, MOIST, MEDIUM DENSE,
SILTY SAND/SANDY SILT
LIGHT BROWN TO REDDISH BROWN, MOIST,
MEDIUM DENSE, SILTY SAND/SANDY SILT
QafQop6-7
1 2
1
10.5
60.42'
(760) 839-7302
DESIGN GROUP
ENGINEERING
SAN MARCOS, CA 92069
2121 MONTIEL ROAD
FAX (760) 480-7477
ADDITIONAL NOTES / COMMENTS:
PROJECT NUMBER
PROJECT NAME
LOCATION
LOG OF BORING No.
SHEET _ OF _
B-
DATE DRILLED
DEPTH
(feet)
SAMPLE
DRILLING METHOD
AND TYPE OF RIG
TOTAL DEPTH
DRILLED (feet)
LOGGED BY BACKFILLED/CONVERTED TO WELL ON(date)APPROX SURFACE
ELEVATION (feet)
DIAMETER OF BORING GROUNDWATER
LEVEL (feet BGS)
FIRST
NONE
COMPLETION
NONE
SAMPLE
NUMBER
BLOW *
COUNTS
SPT
N **
GRAPHIC
LOG MATERIAL DESCRIPTION AND
NOTES
WATER
CONTENT
TYPE OF
SAMPLER(S)CALIFORNIA
SPT TYPE OF
HAMMER
WEIGHT (lbs)
140
DROP (in.)
30SAFTEY
25
20
15
GOTZ RESIDENCE
247114-1
3451 GARFIELD STREET, CARLSBAD, CA 92008
6"
TRIPOD RIG
2
SN/RM
1-17-2025
ELEVATION
(feet)
25
20
15
10
5
2
1
3
4
5
6
7
8
9
10
24
11
12
13
14
16
17
18
19
21
22
23
1
2
3
4
3,3
4 7
18
12
17
6,8
10
3,5
7
7,8
9
0' - 2' LIGHT BROWN TO REDDISH BROWN, LOOSE SILTY SAND
REDDISH BROWN, SLIGHTLY MOIST, LOOSE, SILTY SAND/
SANDY SILT
REDDISH BROWN, MOIST, MEDIUM DENSE, SILTY
SAND/SANDY SILT
REDDISH BROWN, MOIST, MEDIUM DENSE, SILTY SAND/
SANDY SILT
BROWN TO REDDISH BROWN, MOIST, MEDIUM DENSE,
SILTY SAND/SANDY SILT
QafQop6-7
5
6
7,8
9 17
7,11
11 22
REDDISH BROWN, MOIST, MEDIUM DENSE, SILTY SAND/
SANDY SILT
REDDISH BROWN, MOIST, MEDIUM DENSE, SILTY SAND/
SANDY SILT
2 2
2
13.5
61.80'
GA
R
F
I
E
L
D
S
T
R
E
E
T
MAPLE AVENUE
LOT 11BLK C
MAP 1747
3
Qaf/
(Qop6-7)Qaf/
(Qop6-7)
Qaf/
(Qop6-7)
Qop6-7
Qaf Qop6-7
Qaf
Feet
0 20 40
1
*
3451 GARFIELD STREET
CARLSBAD, CA 92008
247114-1
01-28-2025 FIGURE NO.:
JOB NAME:
JOB ADDRESS:
JOB NO.:
DATE:
GOTZ RESIDENCE
APPENDIX A
REFERENCES
1. California Geological Survey, Probabilistic Seismic Hazards Mapping Ground Motion Page.
2. California Department of Conservation, Division of Mines and Geology, Fault Rupture Zones in California, Special
Publication 42, Revised 1990.
3. California Department of Conservation, Division of Mines and Geology, DMG Open-File Report 95-04, Landslide
Hazards in the Northern Part of the San Diego County Metropolitan Area, San Diego County, California –
Landslide Hazard Identification Map No. 35 – Oceanside and San Luis Rey Quadrangle (Plate A), dated 1995.
4. Day, Robert W. 1999. Geotechnical and Foundation Engineering Design and Construction. McGraw Hill.
5. Greensfelder, R.W., 1974 Maximum Credible Rock Acceleration from Earthquakes in California Division of Mines
and Geology, Map Sheet 23.
6. Spaces Renewed – Proposed Feasibility Plan – Gotz Residence, 3451 Garfield Street, Carlsbad, CA 92008, dated
12/6/2024.
7. Kennedy, Michael M.P., Tan, S.S., et. al., Geologic Map of the Oceanside, San Luis Rey, and San Marcos 7.5’
Quadrangles, San Diego County, California, dated 1996.
8. Lee, L.J., 1977, Potential foundation problems associated with earthquakes in San Diego, in Abbott, P.L. and
Victoria, J.K., eds. Geologic Hazards in San Diego, Earthquakes, Landslides, and Floods: San Diego Society of
Natural History John Porter Dexter Memorial Publication.
9. Ploessel, M.R. and Slossan, J.E., 1974 Repeatable High Ground Acceleration from Earthquakes: California
Geology, Vol. 27, No. 9, P. 195-199.
10. State of California, Fault Map of California, Map No. 1, Dated 1975.
11. State of California, Geologic Map of California, Map No. 1, Dated 1977.
12. Structural Engineers Association of Southern California (SEAOSC) Seismology Committee, Macroseminar
Presentation on Seismically Induced Earth Pressure, June 8, 2006.
13. U.S. Army Corps of Engineers, Coast of California Storm and Tidal Waves Study, Shoreline Movement Data
Report, Portuguese Point to Mexican Border, dated December 1985.
14. U.S. Army Corps of Engineers, Coast of California Storm and Tidal Waves Study, Coastal Cliff Sediments, San
Diego Region (CCSTWS 87-2), dated June 1985.
15. Van Dorn, W.G., 1979 Theoretical aspects of tsunamis along the San Diego coastline, in Abbott, P.L. and Elliott,
W.J., Earthquakes and Other Perils: Geological Society of America field trip guidebook.
16. Various Aerial Photographs.
APPENDIX B
General Earthwork and Grading Specifications
1.0 General Intent
These specifications are presented as general procedures and recommendations for grading and
earthwork to be utilized in conjunction with the approved grading plans. These general earthwork
and grading specifications are a part of the recommendations contained in the geotechnical report
and shall be superseded by the recommendations in the geotechnical report in the case of conflict.
Evaluations performed by the consultant during the course of grading may result in new
recommendations which could supersede these specifications or the recommendations of the
geotechnical report. It shall be the responsibility of the contractor to read and understand these
specifications, as well as the geotechnical report and approved grading plans.
2.0 Earthwork Observation and Testing
Prior to commencement of grading, a qualified geotechnical consultant should be employed for the
purpose of observing earthwork procedures and testing the fills for conformance with the
recommendations of the geotechnical report and these specifications. It shall be the responsibility
of the contractor to assist the consultant and keep him apprised of work schedules and changes, at
least 24 hours in advance, so that he may schedule his personnel accordingly. No grading
operations should be performed without the knowledge of the geotechnical consultant. The
contractor shall not assume that the geotechnical consultant is aware of all grading operations.
It shall be the sole responsibility of the contractor to provide adequate equipment and methods to
accomplish the work in accordance with the applicable grading codes and agency ordinances,
recommendations in the geotechnical report and the approved grading plans not withstanding the
testing and observation of the geotechnical consultant If, in the opinion of the consultant,
unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction,
adverse weather, etc., are resulting in a quality of work less than recommended in the geotechnical
report and the specifications, the consultant will be empowered to reject the work and recommend
that construction be stopped until the conditions are rectified.
Maximum dry density tests used to evaluate the degree of compaction shouls be performed in
general accordance with the latest version of the American Society for Testing and Materials test
method ASTM D1557.
3.0 Preparations of Areas to be Filled
3.1 Clearing and Grubbing: Sufficient brush, vegetation, roots and all other deleterious material
should be removed or properly disposed of in a method acceptable to the owner, design
engineer, governing agencies and the geotechnical consultant.
The geotechnical consultant should evaluate the extent of these removals depending
on specific site conditions. In general, no more than 1 percent (by volume) of the fill material
should consist of these materials and nesting of these materials should not be allowed.
3.2 Processing: The existing ground which has been evaluated by the geotechnical consultant
to be satisfactory for support of fill, should be scarified to a minimum depth of 6 inches.
Existing ground which is not satisfactory should be overexcavated as specified in the
following section. Scarification should continue until the soils are broken down and free of
large clay lumps or clods and until the working surface is reasonably uniform, flat, and free
of uneven features which would inhibit uniform compaction.
3.3 Overexcavation: Soft, dry, organic-rich, spongy, highly fractured, or otherwise unsuitable
ground, extending to such a depth that surface processing cannot adequately improve the
condition, should be overexcavated down to competent ground, as evaluated by the
geotechnical consultant. For purposes of determining quantities of materials overexcavated,
a licensed land surveyor / civil engineer should be utilized.
3.4 Moisture Conditioning: Overexcavated and processed soils should be watered, dried back,
blended and / or mixed, as necessary to attain a uniform moisture content near optimum.
3.5 Recompaction: Overexcavated and processed soils which have been properly mixed,
screened of deleterious material and moisture-conditioned should be recompacted to a
minimum relative compaction of 90 percent or as otherwise recommended by the
geotechnical consultant.
3.6 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal
to vertical), the ground should be stepped or benched. The lowest bench should be a
minimum of 15 feet wide, at least 2 feet into competent material as evaluated by the
geotechnical consultant. Other benches should be excavated into competent material as
evaluated by the geotechnical consultant. Ground sloping flatter than 5:1 should be benched
or otherwise overexcavated when recommended by the geotechnical consultant.
3.7 Evaluation of Fill Areas: All areas to receive fill, including processed areas, removal areas
and toe-of-fill benches, should be evaluated by the geotechnical consultant prior to fill
placement.
4.0 Fill Material
4.1 General: Material to be placed as fill should be sufficiently free of organic matter and other
deleterious substances, and should be evaluated by the geotechnical consultant prior to
placement. Soils of poor gradation, expansion, or strength characteristics should be placed
as recommended by the geotechnical consultant or mixed with other soils to achieve
satisfactory fill material.
4.2 Oversize: Oversize material, defined as rock or other irreducible material with a maximum
dimension of greater than 6 inches, should not be buried or placed in fills, unless the
location, materials and disposal methods are specifically recommended by the geotechnical
consultant. Oversize disposal operations should be such that nesting of oversize material
does not occur, and such that the oversize material is completely surrounded by compacted
or densified fill. Oversize material should not be placed within 10 feet vertically of finish
grade, within 2 feet of future utilities or underground construction, or within 15 feet
horizontally of slope faces, in accordance with the attached detail.
4.3 Import: If importing of fill material is required for grading, the import material should meet
the requirements of Section 4.1. Sufficient time should be given to allow the geotechnical
consultant to observe (and test, if necessary) the proposed import materials.
5.0 Fill Placement and Compaction
5.1 Fill Lifts: Fill material should be placed in areas prepared and previously evaluated to
receive fill, in near-horizontal layers approximately 6 inches in compacted thickness. Each
layer should be spread evenly and thoroughly mixed to attain uniformity of material and
moisture throughout.
5.2 Moisture Conditioning: Fill soils should be watered, dried-back, blended and/or mixed, as
necessary to attain a uniform moisture content near optimum.
5.3 Compaction of Fill: After each layer has been evenly spread, moisture-conditioned and
mixed, it should be uniformly compacted to no less than 90 percent of maximum dry density
(unless otherwise specified). Compaction equipment should be adequately sized and be
either specifically designed for soil compaction or of proven reliability, to efficiently achieve
the specified degree and uniformity of compaction.
5.4 Fill Slopes: Compacting of slopes should be accomplished in addition to normal
compacting procedures, by backrolling of slopes with sheepsfoot rollers at increments of 3
to 4 feet in fill elevation gain, or by other methods producing satisfactory results. At the
completion of grading, the relative compaction of fill out to the slope face would be at least
90 percent.
5.5 Compaction Testing: Field tests of the moisture content and degree of compaction of the
fill soils should be performed at the consultant’s discretion based on file dconditions
encountered. In general, the tests should be taken at approximate intervals of 2 feet in
vertical rise and/or 1,000 cubic yards of compacted fill soils. In addition to, on slope faces,
as a guideline approximately one test should be taken for every 5,000 square feet of slope
face and /or each 10 feet of vertical height of slope.
6.0 Subdrain Installation
Subdrain systems, if recommended, should be installed in areas previously evaluated for suitability
by the geotechnical consultant, to conform to the approximate alignment and details shown on the
plans or herein. The subdrain location or materials should not be changed or modified unless
recommended by the geotechnical consultant. The consultant however, may recommend changes
in subdrain line or grade depending on conditions encountered. All subdrains should be surveyed
by a licensed land surveyor / civil engineer for line and grade after installation. Sufficient time shall
be allowed for the survey, prior to commencement of filling over the subdrains.
7.0 Excavation
Excavations and cut slopes should be evaluated by a representative of the geotechnical consultant
(as necessary) during grading. If directed by the geotechnical consultant, further excavation,
overexcavation and refilling of cut areas and/or remedial grading of cut slopes (i.e. stability fills or
slope buttresses) may be recommended.
8.0 Quantity Determination
For purposes of determining quantities of materials excavated during grading and/or determining
the limits of overexcavation, a licensed land surveyor / civil engineer should be utilized.
APPENDIX C
Spaces Renewed – Gotz Residence
3451 Garfield Street, Carlsbad, California Job No. 247114-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
LABORATORY RESULTS
Method Cal-Trans
Analyte Result Reporting
Limit Units Dilution Method
SULFATE 31.9 n/a ppm 1 CT 417
CHLORIDE ND n/a ppm 1 CT 422
p.H. 7.93 n/a pH units 1 CT 643
RESISTIVITY 36400 n/a ohms.com 1 CT 643
ND=None detected – us/cm = micro-Siemens per centimeter - ppm-parts per million
(10,000ppm=1% by weight)
A01165.00001.000 Lab Number:36745
E.D.G.Date Sampled:1/17/2025
L.V.Date Tested:1/22/2025
LAB WORK SHEET EXPANSION INDEX TEST
Initial Final
WET WEIGHT (g)223.1 446.2
DRY WEIGHT (g)202.0 369.0
% MOISTURE (%)10.5 20.9
WEIGHT OF RING & SOIL (g)761.4
WEIGHT OF RING (g)364.7
WEIGHT OF SOIL (lbs.)0.8747
VOLUME OF RING (ft.3)0.0073
WET DENSITY (pcf)120.3
DRY DENSITY (pcf)108.9
% SATURATION (%)51.8
EXPANSION READING
DATE TIME: INITIAL READING INCH
0.0683 VERY LOW 0-20
LOW 21-50
MEDIUM 51 -90
FINAL READING HIGH 91-130
0.0680 VERY HIGH 130>
EXPANSION INDEX
0
NOTES: Equipment ID: 2B
EI at saturation between 48-52%
Measured EI:-0.3
Measured Saturation:51.8
EI at 48-52% Saturation:0
Job Name:GOT 2 (EDG)
Job Number:
Sampled By:
Tested By:
Soil Location:Not Submitted
ASTM D 4829
TEST RESULTS
Soil Description:Reddish Brown (SM)
SHEAR STRENGTH TEST - ASTM D3080
Job Name:
Project Number:1/17/2025
Lab Number:1/29/2025
Sample Location:L.V.
Sample Description:Angle Of Friction:42.0
Cohesion:
Engineering Design Group (Got2)
170 psf
Initial Dry Density (pcf):112.4
Initial Moisture (%):4.8
Final Moisture (%):16.6
Got 2
Reddish Brown (SM)
A01165.00001.000
36745
Sample Date:
Test Date:
Tested By:
2.75
2.8
2.85
2.9
2.95
3
3.05
3.1
3.15
3.20.1 1 10 100
ST
R
A
I
N
(
i
n
c
h
e
s
)
TIME (minutes)
PRECONSOLIDATION
0
1000
2000
3000
4000
5000
0 2 4 6 8 10 12 14 16 18 20
SH
E
A
R
S
T
R
E
S
S
(
p
s
f
)
STRAIN (%)
SHEARING DATA
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000
SH
E
A
R
I
N
G
S
T
R
E
S
S
(
p
s
f
)
VERTICAL STRESS (psf)
FAILURE ENVELOPE
dr=0.08 mm./min
VERTICAL STRESS
1000 psf
3000 psf
5000 psf
Project Name:
Job Number:Lab Number:
Sampled By:Date Sampled:
Tested By:Date Tested:
BORING NO.B-2
DEPTH (ft.)4-5.5
SAMPLE HT. (in.)3.0
SOIL+RING (g)563.7
WT. OF RINGS(g)138.4
WT. OF SOIL (g) 425.3
WT. OF SOIL (lb.)0.9377
VOL. OF RINGS (ft.3)0.00796
WET DENSITY (pcf)117.8
WET WT. (g)638.0
DRY WT. (g)617.7
TARE WT. (g)195.5
% MOISTURE 4.8
DRY DENSITY (pcf)112.4
Tested By:Reviewed By:Lupe Velazquez
GOT 2 (EDG)
L.V.1/28/25.
In Place Moisture & Density Test
Erik Campbell,Operations Manager
EDG
A01165.00001.0000 36745
In Accordance with ASTM D2937
January 17, 2025
APPENDIX D
ENGINEERING DESIGN GROUP