HomeMy WebLinkAboutCDP 2019-0023; HERNANDEZ RESIDENCE; PRELIMINARY GEOTECHNICAL EVALUATION; 2019-10-18 (2)PRELIMINARY GEOTECHNICAL Evaluation
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Chris and Ramon Hernandez
38 Pine Avenue
San Carlos, California 94070 RECORD COPY
Initial Date
PREPARED BY
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GEOTEK, INC.
1384 POINSETTIA AVENUE, SUITE A
VISTA, CALIFORNIA 92081
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PROJECT No. 3592-SD OCTOBER 18, 2019
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G EOT E K
PROPOSED RESIDENTIAL DEVELOPMENT
3677 Garfield Street
CARLSBAD, CALIFORNIA
PREPARED FOR
GeoTek, Inc.
1384 Poinsettia Avenue, Suite A Vista, CA 92081-8505
(760) 599-0509 Otcc (760) 599-0593 F- www.geotekusa.com
October 18, 2019
Project No. 3592-SD
Chris and Ramon Hernandez
3677 Garfield Street
Carlsbad, California
Attention: Chris Hernandez
Subject: Preliminary Geotechnical Evaluation
3677 Garfield Street
Carlsbad, California
Dear Mrs. Hernandez:
We are pleased to provide herein the results of our preliminary geotechnical
evaluation for the subject project located in the City of Carlsbad, California. This report
presents the results of our limited evaluation and provides preliminary geotechnical
recommendations for earthwork, foundation design, and construction. In our opinion,
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 our office.
Respectfully submitted, J'
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GeoTek, Inc. ca
Christpher D. 'F C
((No. C83971
No. 9584
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GEO 9584, Exp. 05/30/21 CM.• &ICE 83971. EXD. 09/30/21
Project Geologist
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Principal Geologist
Distribution: (I) Addressee via email
GEOTECHNICAL I ENVIRONMENTAL I MATERIALS
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ENGINEERING I tP GEOLOGIST
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HERNANDEZ RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street. Carlsbad, California Page i
TABLE OF CONTENTS
I. PURPOSE AND SCOPE OF SERVICES ...................................................................................................... I
SITE DESCRIPTION AND PROPOSED DEVELOPMENT ....................................................................I
2.1 Site Description ..................................................................................................................................... I
2.2 Proposed Development..........................................................................................................................2
FIELD EXPLORATION AND LABORATORY TESTING
3.1 Field Exploration....................................................................................................................................2
3.2 Percolation Testing...............................................................................................................................2
3.3 Laboratory Testing.................................................................................................................................3
GEOLOGIC AND SOILS CONDITIONS....................................................................................................4
4.1 Regional Setting.....................................................................................................................................4
4.2 EARTH MATERIALS..............................................................................................................................4
4.2.1 Undocumented Fill.................................................................................................................................4
4.2.2 Old Paralic Deposits...............................................................................................................................4
4.3 SURFACE WATER AND GROUNDWATER.............................................................................................5
4.3.1 Surface Water.......................................................................................................................................5
4.3.2 Groundwater.........................................................................................................................................5
4.4 EARTHQUAKE HAZARDS.....................................................................................................................5
4.4.1 Surface Fault Rupture............................................................................................................................5
4.4.2 Liquefaction/Seismic Settlement ............................................................................................................. 5
4.4.3 Other Seismic Hazards..........................................................................................................................6
S. CONCLUSIONS AND RECOMMENDATIONS .......................................................................................6
5.1 General.................................................................................................................................................6
5.2 EARTHWORK CONSIDERATIONS ........................................................................................................6
5.2.1 General.................................................................................................................................................6
5.2.2 Site Clearing and Preparation.................................................................................................................7
5.2.3 Remedial Grading..................................................................................................................................7
5.2.4 Engineered Fill.......................................................................................................................................8
5.2.5 Excavation Characteristics......................................................................................................................8
5.2.6 Shrinkage and Bulking...........................................................................................................................8
5.2.7 Trench Excavations and Backfill ............................................................................................................. 8
5.3 DESIGN RECOMMENDATIONS............................................................................................................9
5.3.1 Storm water Infiltration ... ........................................................................................................................9
5.3.2 Foundation Design Criteria.....................................................................................................................9
5.3.3 Underslab Moisture Membrane............................................................................................................11
5.3.4 Miscellaneous Foundation Recommendations........................................................................................12
5.3.5 Foundation Set Backs...........................................................................................................................12
5.3.6 Seismic Design Parameters..................................................................................................................13
5.3.7 Soil Sulfate Content.............................................................................................................................13
5.4 RETAINING WALL DESIGN AND CONSTRUCTION.............................................................................14
5.4.1 General Design Criteria........................................................................................................................14
5.4.2 Wall Backfill and Drainage..................................................................................................................15
5.4.3 Restrained Retaining Walls ..................................................................................................................15
5.5 POST CONSTRUCTION CONSIDERATIONS........................................................................................16
5.5.1 Landscape Maintenance and Planting...................................................................................................16
5.5.2 Drainage.............................................................................................................................................16
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HERNANDEZ RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page
TABLE OF CONTENTS
5.6 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS......................................................................17
LIMITATIONS.................................................................................................................................................17
SELECTED REFERENCES............................................................................................................................19
ENCLOSURES
Figure I - Site Location Map
Figure 2 - Boring Location Map
Appendix A - Exploratory Hand Auger Logs and Infiltration Worksheets
Appendix B - Results of Laboratory Testing
Appendix C - General Earthwork Grading Guidelines
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HERNANDEz RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad. California Page I
I. PURPOSE AND SCOPE OF SERVICES
The purpose of this study was to evaluate the geotechnical conditions on the 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 four (4) exploratory hand auger borings onsite and collection of bulk soil
samples for subsequent laboratory testing.
One hand auger boring was excavated as a percolation test.
Laboratory testing of the soil samples collected during the field investigation.
Review and evaluation of site seismicity, and
Compilation of this geotechnical report which presents our findings of pertinent site
geotechnical conditions and geotechnical recommendations for site development.
2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT
2.1 Site Description
The subject project site is located at 3677 Garfield Street in the City of Carlsbad, California
(see Figure I). The site is generally bounded to the northeast by Garfield Drive, and to the
southwest, southeast, and northwest by existing residences. The site is located in a relatively
flat topographic setting with overall area drainage toward the ocean (southwest). Current
improvements include a single-story residence and detached garage. Site surface conditions
generally consisted of landscape and pavement improvements. Based on available aerial
photographs the site was developed between the late 1930s to mid 1940s. Access is via a
driveway off Garfield Street. Total relief across the site is on the order of a few feet, with
localized surface drainage directed towards the ocean.
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2.2 Proposed Development
Based on review of the conceptual site plan prepared by Chereskin Architecture, dated August
14, 2019, proposed development will include a two-story main house constructed with stem
walls and a raised floor, a detached garage with slab-on-grade, pavements, and landscaping.
Access to the site will continue to be provided by a driveway off Garfield Street, however the
new driveway will be along the south property line. The plan reviewed depicts site grades will
be relatively unchanged. Associated improvements are anticipated to consist of a water
infiltration device, wet and dry utilities. A copy of the plan provided is used as the base for the
Boring Location Map (Figure 2) included with this report.
As site planning progresses and additional or revised plans become available, the plans should
be provided to GeoTek for review and comment. 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
Our initial field exploration was conducted on August 21, 2019 with a supplemental
exploration program performed on October I, 2019 and consisted of a site reconnaissance,
excavation of four hand auger borings, collection of bulk soil samples for subsequent
laboratory testing, and a field percolation test. A Professional Engineer from our firm visually
logged the borings and collected soil samples for laboratory analysis. Approximate locations of
exploration locations are presented on the Boring Location Map, Figure 2. A description of
material encountered in the borings is included in Appendix A.
3.2 Percolation Testing
Boring P-1 was excavated as a percolation test hole. Following completion of the boring,
percolation testing was performed by a representative from our firm in general conformance
with the City of Carlsbad BMP Design Manual. The borehole was presoaked overnight and the
testing was performed on the following day. Percolation testing was performed by adding
potable water to the borings, recording the initial depth to water and allowing the water to
percolate for 10 minutes and the depth to water was measured. Water was generally added to
each boring following each reading increment. In general, the percolation testing was
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performed for approximately 2 hours to allow rates to stabilize. Results of the final percolation
increment were used to calculate an infiltration rate in inches per hour via the Porchet method.
For design of shallow infiltration basins, converting percolation rates to infiltration rates via the
Porchet method is generally acceptable and appropriate, as this method factors out the sidewall
component of the percolation results and represents the bottom conditions of a shallow basin
(infiltration). Therefore, the percolation data for boring P-I was converted via the Porchet
method. This method is consistent with the guidelines referenced in the City of Carlsbad BMP
Design Manual. Results of our infiltration analysis without a factor of safety are presented in
the follow table for the test area.
I I Depth I Infiltration Rate I Location I (inches) (inches per hour)* I
I P-I 60 I 1.69 I
* Rate was converted to an infiltration rate via the Porchet method
Copies of the infiltration conversion sheet are included in Appendix A.
The material exposed along the boring sidewalls and at the bottom of P- I was native soil. The
test performed and reported are indicative of the respective soil type exposed, with the
understanding that compaction during grading, whether intentional or unintentional, may
change the infiltration rate.
Over the lifetime of the storm water disposal areas, the percolation rates may be affected by
silt build up and biological activities, as well as local variations in soil conditions. An appropriate
factor of safety used to compute the design infiltration rate should be considered at the
discretion of the design engineer and acceptance of the plan reviewer.
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.
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Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad. California Page 4
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. Basically, it
extends roughly 975 miles from the north and northeasterly adjacent the Transverse Ranges
geomorphic province to the tip of Baja California. This province varies in width from about 30
to 100 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.
I 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
I 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
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Newport-Inglewood-Rose Canyon Fault zone borders the southwest margin of the province.
No faults are shown in the immediate site vicinity on the map reviewed for the area.
I 4.2 EARTH MATERIALS
A brief description of the earth materials encountered during our subsurface exploration is
presented in the following sections. Based on our field observations and review of published
geologic maps the subject site is locally underlain by sporadic undocumented fill materials,
colluvium, and soft sedimentary bedrock.
4.2.1 Undocumented Fill
Undocumented fill soils were not locally observed but may be present below flatwork and
existing structures. Other areas of undocumented fill (unmapped) are also likely present on the
site. Undocumented fill soils are not considered suitable for support of structural site
improvements, but may be re-used as engineered fill if properly placed.
4.2.2 Old Paralic Deposits
The most recent regional geologic map showing the overall site geology (Kennedy, 2007),
shows old paralic deposits unit 6-7 at the surface across the site. Based on our site evaluation
old paralic deposits are present beneath the topsoil. In the borings, old paralic deposits were
encountered as poorly graded sand. Descriptions of the old paralic materials as encountered
in our borings are shown on the boring logs included in Appendix A.
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Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page 5
4.3 SURFACE WATER AND GROUNDWATER
4.3.1 Surface Water
Surface water was not observed during our site visit. If encountered during earthwork
construction, surface water on this site is likely the result of precipitation or possibly some
minor surface run-off from immediately surrounding properties. Overall site area drainage is in
a southwesterly direction, toward the ocean. Provisions for surface drainage will need to be
accounted for by the project civil engineer.
4.3.2 Groundwater
Bases on a review of previous work performed in the area, groundwater is not anticipated to
be within 15 of the ground surface at the subject site and is not anticipated to be a factor in
site development. Localized perched groundwater could be present but is also not
anticipated to be a factor in site development.
4.4 EARTHQUAKE HAZARDS
4.4.1 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 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 "Aiquist-Priolo" Earthquake Fault Zone or a Special Studies Zone (Bryant and
Hart, 2007). No faults are identified on the readily available geologic maps reviewed for the
immediate study area.
4.4.2 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.
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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 nature of old paralic deposits in the area and absence of a shallow groundwater table.
4.4.3 Other Seismic Hazards
Evidence of ancient landslides or slope instabilities at this site was not observed during our
investigation. Thus, the potential for landslides is considered negligible.
The potential for secondary seismic hazards such as seiche and tsunami is considered to be
remote due to site elevation and distance from an open body of water, as confirmed by the
CalEMA Oceanside/San Luis Rey Tsunami Inundation Map.
S. CONCLUSIONSAND 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
5.2.1 General
Earthwork and grading should be performed in accordance with the applicable grading
ordinances of the City of Carlsbad, the 2016 (or current) California Building Code (CBC), and
I 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
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5.2.2 Site Clearing and Preparation
Site preparation should start with demolition of the existing structures and removal of
deleterious materials and vegetation. 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.
5.2.3 Remedial Grading
Prior to placement of fill materials, the upper loose and compressible materials should be
removed for structural site areas that will be constructed as slab-on-grade. Removal depths in
unmapped areas of existing undocumented fill and highly weathered paralic deposits are
estimated to be up to approximately 3 feet. The lateral extent of removals beyond the outside
edge of all settlement sensitive structures/foundations should be equivalent to that vertically
removed. Depending on actual field conditions encountered during grading, locally deeper
and/or shallower areas of removal may be necessary.
At a minimum, the cut portion(s) of any slab-on-grade building pad areas in site formational or
suitable material(s) should be overexcavated a minimum of three (3) feet below finish pad grade
or a minimum of two (2) feet below the bottom of the deepest proposed footing, whichever is
deeper. Overexcavations should extend a minimum of three (3) feet outside the proposed
building envelope(s).
Areas that will support pavements should be overexcavated a minimum of one (I) foot below
the bottom of the pavement. Where possible, overexcavations should extend a minimum of
two (2) feet outside the proposed pavement envelope(s).
The intent of the recommended overexcavation is to support the improvements on engineered
fill with relatively uniform engineering characteristics and decrease the potential for differential
settlement
The bottom of all removals should be scarified to a minimum depth of six (6) inches, brought to
at or above optimum moisture content, and then compacted to minimum project standards
prior to fill placement. The remedial excavation bottoms should be observed by a GeoTek
representative prior to scarification. The resultant voids from remedial grading/overexcavation
should be filled with materials placed in general accordance with Section 5.2.4 Engineered Fill of
this report.
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5.2.4 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 in accordance with laboratory test procedure ASTM
D 1557.
5.2.5 Excavation Characteristics
Excavations in the onsite undocumented fill and old paralic materials can generally be
accomplished with heavy-duty earthmoving or excavating equipment in good operating
condition. Less weathered bedrock materials are also likely to be encountered at depth and
could locally require special techniques to excavate.
5.2.6 Shrinkage and Bulking
Several factors will impact earthwork balancing on the site, including old paralic bulking, and
possible shrinkage of undocumented fill, trench spoil from utilities and footing excavations, as
well as the accuracy of topography.
Shrinkage and bulking are largely dependent upon the degree of compactive effort achieved
during construction. For planning purposes, a shrinkage factor ranging from 5 to 15 percent
may be considered for the paralic and undocumented fill materials requiring removal and re-
compaction. Subsidence should not be a factor on the subject site if removals are completed
down to the recommended depths to expose bedrock materials. Site balance areas should be
available in order to adjust project grades, depending on actual field conditions at the
conclusion of site earthwork construction.
5.2.7 Trench Excavations and Backfill
Temporary excavations within the onsite materials should be stable at 1: I 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.
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Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page 9
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 per ASTM D 1557. Under-slab trenches should also be
compacted to project specifications.
Onsite materials may be suitable for use as bedding material and backfill provided particles
larger than 3± 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
5.3.1 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. Preliminary plans do not show proposed locations for
stormwater quality basins, however based on discussions with you, we understand that a
singular basin will be located at the rear of the lot, between the proposed garage and the
existing block wall.
Due to the proximity of existing and proposed foundations, we recommend that infiltration
surfaces (bottom of basin, trench, or other device) be located at a minimum depth of 5 feet
below ground surface.
5.3.2 Foundation Design Criteria
Preliminary foundation design criteria, in general conformance with the 2016 CBC, are
presented herein. Based on our investigation and understanding of the proposed construction,
the following criteria are for slab-on-grade foundations bearing on engineered fill and for stem
wall foundations bearing upon paralic deposits. These are typical design criteria and are not
intended to supersede the design by the structural engineer.
Based on our visual classification of materials encountered onsite and as verified by laboratory
testing, soils near subgrade are "very low" expansive (El20) per ASTM D4829. Additional
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laboratory testing should be performed at the completion of site grading to verify the
expansion potential and plasticity index, if necessary, of the subgrade soils.
The following criteria for design of foundations are preliminary. Additional laboratory testing of
the samples obtained during grading should be performed and final recommendations should be
based on as-graded soil conditions.
MINIMUM DESIGN REQUIREMENTS FOR CONVENTIONALLY REINFORCED
FOUNDATIONS
DESIGN PARAMETER "Very Low"
Expansion _Potential _(O!5EI!520)
Foundation Embedment Depth or Minimum Perimeter One-Story - 12
Beam Depth (inches below lowest adjacent finished Two-Story - 18
grade) Three-Story - 24
Supporting One Floor - 12
Minimum Foundation Width (inches)* Supporting Two Floors - IS
Supporting _Three _Floors _-_18
Minimum Slab Thickness (actual) 4 inches
Minimum Slab Reinforcing No. 3 rebar 24" on-center, each way, placed in the
middle one-third of the slab thickness
Minimum Footing Reinforcement Two No. 4 Reinforcing Bars, one (I) top and one
(I) bottom
Presaturation of Subgrade Soil for Slab-on-Grade Minimum 100% to a depth of 12 inches
(percent of optimum moisture content)
*Code minimums per Table 1809.7 of the 2016 CBC should be complied with.
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.
The following recommendations should be implemented into the design:
An allowable bearing capacity of 2000 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 400 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 3000 psf. Additionally,
an increase of one-third may be applied when considering short-term live loads (e.g.
seismic and wind loads).
Based on our experience in the area, structural foundations may be designed in
accordance with 2016 CBC, and to withstand a total settlement of I inch and
maximum differential settlement of one-half of the total settlement over a
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horizontal distance of 40 feet. These values assume that seismic settlement
potential is not a significant constraint.
The passive earth pressure may be computed as an equivalent fluid having a density
of 250 psf per foot of depth, to a maximum earth pressure of 2500 psf for footings
founded on engineered fill. A coefficient of friction between soil and concrete of
0.35 may be used with dead load forces. When combining passive pressure and
frictional resistance, the passive pressure component should be reduced by one-
third.
A grade beam, a minimum of 12 inches wide and 12 inches deep, should be utilized
across large entrances, however, the base of the grade beam should be at the same
elevation as the bottom of the adjoining footings.
5.3.3 Underslab 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 2016
California Green Building Standards Code (CALGreen) Section 4.505.2 and the 2016 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.
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3677 Garfield Street, Carlsbad, California Page 12
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, we recommend 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 our services in general are not intended to
address mold prevention; since we, 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.
We recommend 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.
5.3.4 Miscellaneous Foundation Recommendations
To reduce moisture penetration beneath the slab on grade areas, utility trenches
should be backfllled 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 compacted and tested. The excavations should be free of
loose/sloughed materials and be neatly trimmed at the time of concrete placement.
5.3.5 Foundation Set Backs
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:
G EOTEK
HERNANDEZ RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page 13
The bottom of all footings for structures near retaining walls should be deepened so
as to extend below a I: I 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 so as to
extend below a I I projection upward from the bottom of the nearest excavation.
5.3.6 Seismic Design Parameters
The site is located at approximately 33.1504 Latitude and - 117.3460 Longitude. Site spectral
accelerations (Ss and S I), 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. We have selected a Site Class "C" based on the old paralic deposits and
anticipated depth of fill.
SITE SEISMIC PARAMETERS
Mapped 0.2 sec Period Spectral Acceleration, Ss I .1 59g
Mapped 1.0 sec Period Spectral Acceleration, Si 0.444g
Site Coefficient for Site Class "C", Fa 1.000
Site Coefficient for Site Class "C", Fv 1.356
Maximum Considered Earthquake (MCER) Spectral 1159 g Response Acceleration for 0.2 Second, SMs
Maximum Considered Earthquake (MCER) Spectral 0.602g g Response Acceleration for 1.0 Second, SMI
5% Damped Design Spectral Response 0773 g Acceleration Parameter at 0.2 Second, SDS
5% Damped Design Spectral Response 0402 g Acceleration Parameter at I second, SDI
5.3.7 Soil Sulfate Content
The sulfate content was determined in the laboratory for a soil sample collected during the
field investigation. The results indicate that the water soluble sulfate is less than 0.1 percent by
weight, which is considered "SO" as per Table 19.3.1.1 of ACI 318-14, as such no special
recommendations for concrete are included herein.
G EOTEK
HERNANDEz RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page 14
5.4 RETAINING WALL DESIGN AND CONSTRUCTION
5.4.1 General Design Criteria
Base on a review of project plans, retaining walls are anticipated to be limited to relatively
short stem walls supporting the main house structure, however, in the event changes are made
to the plan the recommendations presented herein may apply to typical masonry or concrete
vertical retaining walls to a maximum height of 10 feet. Additional review and
recommendations should be requested for higher walls.
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 2000 psf. An
increase of one-third may be applied when considering short-term live loads (e.g. seismic and
wind loads). The passive earth pressure may be computed as an equivalent fluid having a
density of 250 psf per foot of depth, to a maximum earth pressure of 2500 psf. A coefficient of
friction between soil and concrete of 0.35 may be used with dead load forces. When
combining passive pressure and frictional resistance, the passive pressure component should be
reduced by one-third.
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 Equivalent Fluid Pressure
Materials (PCF)
(H:V) Select Backfill*
Level 35
2:1 55
*Select backfill should consist of native or imported sand other
approved materials with an SE>30 and an E120.
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.
Additional lateral forces can be induced on retaining walls during an earthquake. For level
backfill and a Site Class "C", the minimum earthquake-induced force (Feq) should be I OH
(lbs/linear foot of wall) for cantilever walls. This force can be assumed to act at a distance of
0.6H above the base of the wall, where "H" is the height of the retaining wall measured from
the base of the footing (in feet). The 2016 CBC only requires the additional earthquake
induced lateral force be considered on retaining walls in excess of six (6) feet in height
G FOTEK
HERNANDEZ RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street. Carlsbad, California Page IS
however, the additional force may be applied in design of lesser walls at the discretion of the
wall designer.
5.4.2 Wall Backfill and Drainage
Wall backfill should include a minimum one (I) foot wide section of 3/4 to I-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: I (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 (I) cubic foot
per lineal foot of 3/8 to one (I) 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.
Drain outlets should be maintained over the life of the project and should not be obstructed
or plugged by adjacent improvements.
5.4.3 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 60 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.
G EOTEK
HERNANDEz RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page 16
5.5 POST CONSTRUCTION CONSIDERATIONS
5.5.1 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 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. We could discuss these issues, if desired, when plans are
made available.
5.5.2 Drainage
The need to maintain proper surface drainage and subsurface systems cannot be overly
emphasized. Positive site drainage should be maintained at all times. Water should be directed
away from foundations toward approved infiltration basins and not allowed to pond' or seep
into the ground. Pad drainage should be directed toward approved area(s) and not be blocked
by other improvements.
It is the owner's responsibility to maintain and clean drainage devices on or contiguous to their
lot. In order to be effective, maintenance should be conducted on a regular and routine
schedule and necessary corrections made prior to each rainy season.
G EOTEK
HERNANDEZ RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street. Carlsbad, California Page 17
5.6 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS
We recommend that changes to site grading, specifications, and any 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. We also recommend 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.
. 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.
. 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 Geolek,
which can comply with the requirements of the governmental agencies having jurisdiction over
the project. We recommend that these agencies be notified prior to commencement of
construction so that necessary grading permits can be obtained.
6. LIMITATIONS
The scope of our evaluation is limited to the area explored that is shown on the Boring
Location 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. Further, no evaluation of any existing site improvements is included. The scope is
based on our understanding of the project and the client's needs, our proposal (Proposal No.
P0801919-SD) dated August 16, 2019 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
G EOTEK
1
HERNANDEZ RESIDENCE Project No. 3592-SD
I Preliminary Geotechnical Evaluation October 1$, 2019
3677 Garfield Street, Carlsbad, California Page 18
I or other factors. GeoTek, Inc. assumes no responsibility or liability for work, testing or
recommendations performed or provided by others.
I Since our recommendations are based on the site conditions observed and encountered, and
laboratory testing, our 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
I implied. Standards of practice are subject to change with time.
P L
G EOTEK
HERNANDEZ RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page 19
7. SELECTED REFERENCES
American Society of Civil Engineers (ASCE), 2013, "Minimum Design Loads for Buildings and
Other Structures," ASCE/SEI 7-10, Third Printing, Errata Incorporated through March 15.
Armstrong & Brooks Consulting Engineers, 2017, Grading Plans for: 3677 Garfield St, Carlsbad,
CA 92008, APN:204-232-04, Sheets I and 2, dated February IS, 2017.
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, 2016 "California Building Code," 3 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.
Chereskin Architecture, Plans for Hernandez Residence, 3677 Garfield Street, Carlsbad,
California, 92008, 8 Sheets, IS and A- I through A-7, dated August 14, 2019.
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.
Structural Engineers Association of California/California Office of Statewide Health Planning
and Development (SEOC/OSHPD), 2019, Seismic Design Maps web interface, accessed
October 19, 2019 at https://seismicmaps.org
G EOTEK
APPENDIX A
EXPLORATORY HAND AUGER LOGS
AND
INFILTRATION TESTING WORKSHEETS
G EOTEK
HERNANDEZ RESIDENCE Project No. 3592-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page A-I
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.
B —EXPLORATION LOG LEGEND
The following abbreviations and symbols often appear in the classification and description of soil and
rock on the logs of borings and trenches:
SOILS
USCS Unified Soil Classification System
f-c Fine to coarse
f-m Fine to medium
GEOLOGIC
Attitudes Bedding strike/dip
J: Attitudes Joint strike/dip
Contact line
Dashed line denotes USCS material change
Solid Line denotes unit / formational change
Thick solid line denotes end of boring
(Additional denotations and symbols are provided on the logs)
I
I
G EOTEK
GeoTek, Inc.
LOG OF EXPLORATORY BORING
CLIENT: Chris & Ramon Hernandez DRILLER: . LOGGED BY: BG
PROJECT NAME: 3677carseld DRILL METHOD:Hand Auger OPERATOR:_________________ PROJECT NO.: 592-sD HAMMER: - RIG TYPE: -
LOCATION: See Boring Location Map ELEVATION: so ft DATE: 812112019
- SAMPLES - Laboratory Testing -
q rz - HAND AUGER NO.: HA-1 (WI to a
MATERIAL DESCRIPTION AND COMMENTS
6" Topsoil and grass
Quaternary Old Paralic Deposits
SP SAND, reddish brown, moist, fine to medium grained, poorly graded El, SR
5.--- --
HOLE TERMINATED AT 5 FT
No groundwater encountered
Hole backflhled with soil cuttings
10
15
20
25
30
sample type W —Ring —SPT Z—Small Bulk s—Large Bulk —No Recovery —Water Table
AL = "'gLimits El = Expansion Index SA = Sieve Analysis RV • R-Value Test Lab testing. SR = Sulfate!Reslsltivlty Test SH = Shear Test CO = Consolidation test MD = Maximum Density
GeoTek, Inc.
CLIENT:
PROJECT NAME:
PROJECT NO.:
LOCATION:
LOG OF EXPLORATORY BORING
Chris & Ramon Hernandez DRILLER: . LOGGED BY: BG
3677 Garfield DRILL METHOD:Hand Auger OPERATOR: -
See Bonng Location Map
3592-SD
ELEVATION: 60ft DATE: w2112019
HAMMER:_- RIG TYPE:__________________
- SAMPLES Laboratory Testing -
to HAND AUGER NO.: HA-2 CL
]JEL
M
T z U) D a, MATERIAL DESCRIPTION AND COMMENTS
6" Topsoil andgrass
Quaternan, Old Parafic DeDoelts
- SP @6" SAND, brown to reddish brown, very moist f-rn grained, poorly graded, El, SR
X
@24" Probes dense
@30" SAND, mottled white, tan, and black, moist, f-rn grained, trace silt
- @36" becomes reddish brown
Auger refusal. concretion bits incuttings - -
5. HOLE TERMINATED AT 4 FT
Refusal at 4 feet
- No groundwater encountered
Hole backfilled with soil cuttings
10
15
20
25
30
Sample typo f]._Rlng ]_SPT 21—Small BIjIr s—Large Buar 1:1 —No Recovery —water Table
UI _1 Lab testing- AL = Attertrerg Limits El = Expansion Index SA = Sieve Analysis RV = R.Value Test
SR = SulfatelReslsltMty Test SH = Shear Test CO = Consotidation test MD • Maximum Density
GeoTek, Inc.
LOG OF EXPLORATORY BORING
CLIENT: Chits & Ramon Hernandez DRILLER: LOGGED BY: BG
PROJECT NAME: 3677 Garfield DRILL METHOD: Hand Auger OPERATOR: PROJECT NO.: 3692-SD HAMMER: _- RIG TYPE: LOCATION: See Baring Location Map ELEVATION: 59 It DATE: 812112019
- SAMPLES -
I
Laboratory Testing -
HANDAUGERNO.:HA-3 ' CL fi 0 MATERIAL DESCRIPTION AND COMMENTS
- - - - - 6" Topsoilandgrass
Quatemary Old Parafic DeDosits
- SM @6" Silty SAND, light brown, dry to slightly moist, f grained, poorly graded El, SR
• Augenng becomes difficult, concretion bits/sandstone returned hard though
- friable
Hand augering becomes difficult, friable sandstone concretions returned
• - - _____ in cuttings
- SP SAND, reddish brown, moist, f-rn grained, poorly graded
5---- --
HOLE TERMINED AT 5 FT
No groundwater encountered
Hole backfilled with soil cuttings
10
15
20
25
30
Sample type 1—Ring [_SPT s—Small Buik s—Large Bulk [] —No Recovery —Water Table
a__as__flu Lab Al. = Afleberg Limits El = Expansion Index SA = Sieve Analysis RV = R-Value Test
_ SR.SutfatelResisltivityTest SH= Shear Test CO= Consolidation test MD= Maximum Density
GeoTek, Inc.
LOG OF EXPLORATORY BORING
CLIENT: Chris & Rarnon Hernandez DRILLER: . LOGGED BY: SE
PROJECT NAME: 3577anei DRILL METHOD: Hand Auger OPERATOR: - PROJECT NO.: 3592-SD HAMMER: RIG TYPE:__________________ LOCATION: See Boting Location Map ELEVATION: 59f1 DATE: 101112019
SAMPLES Laboratory Testing -
HAND AUGER NO.: P-I
CL
l--i
H -EL
___________________
- -
C' MATERIAL DESCRIPTION AND COMMENTS
• : ______ 6" Topsoil and grass
Quaternary Old Paralic Deposits
- SM @6" Silty SAND, light brown, dry to slightly moist, f grained, poorly graded
SP @4' SAND, reddish brown, moist, f-rn grained, poorly graded
5.---- --
HOLE TERMINED AT 5 FT
No groundwater encountered
- Hole pre-soaked with potable water on 10-1 -19
Hole backfifled with soil cuttings on 10.2.19
10
15 -
20 -
25 -
30
jj Sample type: 1J —Ring []-_SPT Z—Small Bulk [K—Large Bulk 1:1 —No Recovery —Water Table
_I - Lab testing: Al. = Atletberg Limits El = Expansion Index SA = Sieve Analysis RV R-Value Test
- SR=SulfatelResldtivityTest SH= Shear Test CO= Consolidation test MD= Maximum Density
Client: Chris and Ramon Hernandez
Project: Hernandez Residence
Project No: 3592-SD
Date: 10/1/2019
Boring No. P-I
Infiltration Rate (Porchet Method)
Time Interval, At = 10
Final Depth to Water, DF = 40.00
Test Hole Radius, r = 1.75
Initial Depth to Water, D0 = 32
Total Test Hole Depth, DT = 60
Equation -
It = AH (60r)
at (r+2H)
HO=DT - DO = 28.00
HF=DT- DF = 20.00
AH = AD = H0- HF = 8.00
Havg = (Ho+HF)/2 = 24.00
I 1.69 1 Inches per Hour
GEOTEK
APPENDIX B
RESULTS OF LABORATORY TESTING
HERNANDEZ RESIDENCE Project No. 3586-SD
Preliminary Geotechnical Evaluation October 18, 2019
3677 Garfield Street, Carlsbad, California Page B-I
SUMMARY OF LABORATORY TESTING
Identification and Classification
Soils were identified visually in general accordance to the standard practice for description and
identification of soils (ASTM D2488). The soil identifications and classifications are shown on the logs
of exploratory borings in Appendix A.
Expansion Index
Expansion Index testing was performed on two soil samples. Testing was performed in general
accordance with ASTM Test Method D 4829. The results of the testing are provided below.
Boring No. Depth
(ft.) Soil Type
I
Expansion Index Classification
HA- I /2/3 I 0-5 I Sand I 0 I Very Low
Moisture-Density Relationship
Laboratory testing was performed on one sample collected during the subsurface exploration. The
laboratory maximum dry density and optimum moisture content for the soil type was determined in
general accordance with test method ASTM Test Procedure D1557. The results of the testing are
provided below.
Boring No Depth I Description Maximum Dry I Optimum MoisturJ
(ft.) I I Density (pcf) I Content (%)
HA- 1/2/3 I 0-5 I Sand with Silt I 123.9 I 9.5
G EOTEK
I
V ProjectX REPORTS19O823A
Corrosion Engineering Page 1 A Corrosion Control - Soil, Water, Metallurgy Testing Lab
Results Only Soil Testing
for
Hernandez Residence
August 27, 2019
Prepared for:
Ben Grenis
GeoTek, Inc.
1384 Poinsettia Ave, Suite A
Vista, CA, 92081
bgrenis@geotekusa.com
Project X Job#: S190823A
Client Job or PO#: 3592-SD
Respectfully Submitted,
Eduardo Hernandez, M.Sc., P.E.
Sr. Corrosion Consultant
NACE Corrosion Technologist #16592
Professional Engineer
California No. M37102
ehernandez@Drojectxcorrosion.com
E SS
No. W702 rn
08A 1A
OF cd
29990 Technology Dr, Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720
www.projectxcorrosion.com
L 11ojectX REPORT S I 90823A
Corrosion Engineering Page 2
Corrosion Control - Soil, Water, Metallurgy Testing Lab
Soil Analysis Lab Results
Client: Geolek, Inc.
Job Name: Hernandez Residence
Client Job Number: 3592-SD
Project Job Number: 5190823A
August 27, 2019
Method ASTM
D4327
Bore# / Depth Sulfates
DescriDtion S042
(ft) (mg/kg) (wt%)
B1/2/3 0.0-5.0 40.1 1 0.0040
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 I NT = Not Tested I Unk = Unknown
Chemical Analysis performed on 1:3 Soil-To-Water extract
29990 Technology Dr., Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720
www.projectxcorrosion.com
APPENDIX C
GENERAL EARTHWORK GRADING GUIDELINES
Grading Guidelines APPENDIX C
Page 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 Uniform Building Code 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
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.
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.
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.
Density tests may be made on the surface material to receive fill, as considered warranted by this
firm.
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.
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 be
G EOTEK
Grading Guidelines APPENDIX C
Page 2
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:
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.
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
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.
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.
Nonorganic debris or concrete may be placed in deeper fill areas provided the procedures used are
observed and found acceptable by our representative. Typical procedures are similar to those
indicated on Plate G-4.
Treatment of Existing Ground
Following site clearing, all surficial deposits of alluvium and colluvium as well as weathered or
creep effected bedrock, should be removed (see Plates G-1, G-2 and 0-3) unless otherwise
specifically indicated in the text of this report.
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.
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.
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.
Exploratory back hoe or dozer trenches still remaining after site removal should be excavated and
filled with compacted fill if they can be located.
Subdrainage
1. Subdrainage systems should be provided in canyon bottoms prior to placing fill, and behind buttress
and stabilization fills and in other areas indicated in the report. Subdrains should conform to
schematic diagrams G-1 and G-5, and be acceptable to our representative.
'JCX'
G £01 E K
Grading Guidelines APPENDIX C
Page 3
For canyon subdrains, runs less than 500 feet may use six-inch pipe. Typically, runs in excess of
500 feet should have the lower end as eight-inch minimum.
Filter material should be clean, 1/2 to 1-inch gravel wrapped in a suitable filter fabric. Class 2
permeable filter material per California Department of Transportation Standards tested by this
office to verify its suitability, may be used without filter fabric. A sample of the material should be
provided to the Soils Engineer by the contractor at least two working days before it is delivered to
the site. The filter should be clean with a wide range of sizes.
Approximate delineation of anticipated subdrain locations may be offered at 40-scale plan review
stage. During grading, this office would evaluate the necessity of placing additional drains.
All subdrainage systems should be observed by our representative during construction and prior to
covering with compacted fill.
Subdrains should outlet into storm drains where possible. Outlets should be located and protected.
The need for backflow preventers should be assessed during construction.
Consideration should be given to having subdrains located by the project surveyors.
Fill Placement
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 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:
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.
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-1 557.
4. Rock fragments less than eight inches in diameter may be utilized in the fill, provided:
They are not placed in concentrated pockets;
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 (See Plate G-4). 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.
'r~
G LOT E K
Grading Guidelines APPENDIX C
Page 4
Slope Construction
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.
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.
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.
Corners and bends in slopes should have special attention during construction as these are the most
difficult areas to obtain proper compaction.
Cut slopes should be cut to the finished surface, excessive undercutting and smoothing of the face
with fill may necessitate stabilization.
Keyways, Buttress and Stabilization Fills
Keyways are needed to provide support for fill slope and various corrective procedures.
1. Side-hill fills should have an equipment-width key at their toe excavated through all surficial soil
and into competent material and tilted back into the hill (Plates G-2, G-3). As the fill is elevated,
it should be benched through surficial soil and slopewash, and into competent bedrock or other
material deemed suitable by our representatives (See Plates 0-I, 0-2, and 0-3).
2. Fill over cut slopes should be constructed in the following manner:
All surficial soils and weathered rock materials should be removed at the cut-fill
interface.
A key at least one (1) equipment width wide (or as needed for compaction) and tipped at
least one (1) foot into slope should be excavated into competent materials and observed
by our representative.
C) The cut portion of the slope should be excavated prior to fill placement to evaluate if
stabilization is necessary, the contractor should be responsible for any additional
earthwork created by placing fill prior to cut excavation.
(See Plate 0-3 for schematic details.)
3. Daylight cut lots above descending natural slopes may require removal and replacement of the
outer portion of the lot. A schematic diagram for this condition is presented on Plate 0-2.
4. A basal key is needed for fill slopes extending over natural slopes. A schematic diagram for this
condition is presented on Plate G-2.
5. All fill slopes should be provided with a key unless within the body of a larger overall fill mass.
Please refer to Plate 0-3, for specific guidelines.
Anticipated buttress and stabilization fills are discussed in the text of the report. The need to stabilize other
proposed cut slopes will be evaluated during construction. Plate G-5 is shows a schematic of buttress
construction.
G EOTEK
Grading Guidelines APPENDIX C
Page 5
All backcuts should be excavated at gradients of 1:1 or flatter. The backcut configuration should
be determined based on the design, exposed conditions and need to maintain a minimum fill width
and provide working room for the equipment.
On longer slopes backcuts and keyways should be excavated in maximum 250 feet long segment.
The specific configurations will be determined during construction.
All keys should be a minimum of two (2) feet deep at the toe and slope toward the heel at least one
foot or two (2%) percent whichever is greater.
Subdrains are to be placed for all stabilization slopes exceeding 10 feet in height. Lower slopes are
subject to review. Drains may be required. Guidelines for subdrains are presented on Plate G-5.
Benching of backcuts during fill placement is required.
Lot Capping
When practical, the upper three (3) feet of material placed below finish grade should be comprised
of the least expansive material available. Preferably, highly and very highly expansive materials
should not be used. We will attempt to offer advise based on visual evaluations of the materials
during grading, but it must be realized that laboratory testing is needed to evaluate the expansive
potential of soil. Minimally, this testing takes two (2) to four (4) days to complete.
Transition lots (cut and fill) both per plan and those created by remedial grading (e.g. lots above
stabilization fills, along daylight lines, above natural slope, etc.) should be capped with a three foot
thick compacted fill blanket.
Cut pads should be observed by our representative(s) to evaluate the need for overexcavation and
replacement with fill. This may be necessary to reduce water infiltration into highly fractured
bedrock or other permeable zones, and/or due to differing expansive potential of materials beneath
a structure. The overexcavation should be at least three feet. Deeper overexcavation may be
recommended in some cases.
ROCK PLACEMENT AND ROCK FILL GUIDELINES
It is anticipated that large quantities of oversize material would be generated during grading. It's likely that
such materials may require special handling for burial. Although alternatives may be developed in the field,
the following methods of rock disposal are recommended on a preliminary basis.
Limited LarEer Rock
When materials encountered are principally soil with limited quantities of larger rock fragments or boulders,
placement in windrows is recommended. The following procedures should be applied:
1. Oversize rock (greater than 8 inch) should be placed in windrows.
Windrows are rows of single file rocks placed to avoid nesting or clusters of rock.
Each adjacent rock should be approximately the same size (within -'one foot in diameter).
C) The maximum rock size allowed in windrows is four feet
2. A minimum vertical distance of three feet between lifts should be maintained. Also, the windrows
should be offset from lift to lift. Rock windrows should not be closer than 15 feet to the face of fill
slopes and sufficient space must be maintained for proper slope construction (see Plate G-4).
3. Rocks greater than eight inches in diameter should not be placed within seven feet of the finished
subgrade for a roadway or pads and should be held below the depth of the lowest utility. This will
allow easier trenching for utility lines.
G EOTEK
Grading Guidelines APPENDIX C
Page 6
4. Rocks greater than four feet in diameter should be broken down, if possible, or they may be placed
in a dozer trench. Each trench should be excavated into the compacted fill a minimum of one foot
deeper than the largest diameter of rock.
The rock should be placed in the trench and granular fill materials (SE>30) should be
flooded into the trench to fill voids around the rock.
The over size rock trenches should be no closer together than 15 feet from any slope face.
C) Trenches at higher elevation should be staggered and there should be a minimum of four
feet of compacted fill between the top of the one trench and the bottom of the next higher
trench.
d) It would be necessary to verify 90 percent relative àompaction in these pits. A 24 to 72
hour delay to allow for water dissipation should be anticipated prior to additional fill
placement.
Structural Rock Fills
If the materials generated for placement in structural fills contains a significant percentage of material more
than six (6) inch in one dimension, then placement using conventional soil fill methods with isolated
windrows would not be feasible. In such cases the following could be considered.
1. Mixes of large of rock or boulders may be placed as rock fill. They should be below the depth of
all utilities both on pads and in roadways and below any proposed swimming pools or other
excavations. If these fills are placed within seven (7) feet of finished grade they may effect
foundation design.
2. Rock fills are required to be placed in horizontal layers that should not exceed two feet in
thickness, or the maximum rock size present, which ever is less. All rocks exceeding two feet
should be broken down to a smaller size, windrowed (see above), or disposed of in non-structural
fill areas. Localized larger rock up to 3 feet in largest dimension may be placed in rock fill as
follows:
individual rocks are placed in a given lift so as to be roughly 50% exposed above the typical
surface of the fill,
loaded rock trucks or alternate compactors are worked around the rock on all sides to the
satisfaction of the soil engineer,
C) the portion of the rock above grade is covered with a second lift.
3. Material placed in each lift should be well graded. No unfilled spaces (voids) should be permitted
in the rock fill.
Compaction procedures:
Compaction of rock fills is largely procedural. The following procedures have been found to generally
produce satisfactory compaction.
Provisions for routing of construction traffic over the fill should be implemented.
Placement should be by rock trucks crossing the lift being placed and dumping at its edge.
The trucks should be routed so that each pass across the fill is via a different path and that
all areas are uniformly traversed.
C) The dumped piles should be knocked down and spread by a large dozer (D-8 or larger
suggested). (Water should be applied before and during spreading.)
2. Rock fill should be generously watered (sluiced)
a) Water should be applied by water trucks to the:
i) dump piles,
G EOTE K
Grading Guidelines APPENDIX C
Page 7
front face of the lift being placed and,
surface of the fill prior to compaction.
b) No material should be placed without adequate water.
C) The number of water trucks and water supply should be sufficient to provide constant
water.
d) Rock fill placement should be suspended when water trucks are unavailable:
for more than 5 minutes straight, or,
for more than 10 minutes/hour.
In addition to the truck pattern and at the discretion of the soil engineer, large, rubber tired
compactors may be required.
The need for this equipment will depend largely on the ability of the operators to provide
complete and uniform coverage by wheel rolling with the trucks.
Other large compactors will also be considered by the soil engineer provided that required
compaction is achieved.
4. Placement and compaction of the rock fill is largely procedural. Observation by trenching should
be made to check:
the general segregation of rock size,
for any unfilled spaces between the large blocks, and
C) the matrix compaction and moisture content.
5. Test fills may be required to evaluate relative compaction of finer grained zones or as deemed
appropriate by the soil engineer.
a) A lift should be constructed by the methods proposed as proposed
6. Frequency of the test trenching is to be at the discretion of the soil engineer.
Control areas may be used to evaluate the contractors procedures.
7. A minimum horizontal distance of 15 feet should be maintained from the face of the rock fill and
any finish slope face. At least the outer 15 feet should be built of conventional fill materials.
Piping Potential and Filter Blankets:
Where conventional fill is placed over rock fill, the potential for piping (migration) of the fine grained
material from the conventional fill into rock fills will need to be addressed.
The potential for particle migration is related to the grain size comparisons of the materials present and in
contact with each other. Provided that 15 percent of the finer soil is larger than the effective pore size of
the coarse soil, then particle migration is substantially mitigated. This can be accomplished with a well-
graded matrix material for the rock fill and a zone of fill similar to the matrix above it. The specific gradation
of the fill materials placed during grading must be known to evaluate the need for any type of filter that
may be necessary to cap the rock fills. This, unfortunately, can only be accurately determined during
construction.
In the event that poorly graded matrix is used in the rock fills, properly graded filter blankets 2 to 3 feet
thick separating rock fills and conventional fill may be needed. As an alternative, use of two layers of filter
fabric (Mirafi 700 x or equivalent) could be employed on top of the rock fill. In order to mitigate excess
puncturing, the surface of the rock fill should be well broken down and smoothed prior to placing the filter
fabric. The first layer of the fabric may then be placed and covered with relatively permeable fill material
(with respect to overlying material) I to 2 feet thick. The relative permeable material should be compacted
to fill standards. The second layer of fabric should be placed and conventional fill placement continued.
G EOT E K
Grading Guidelines APPENDIX C
Page 8
Subdrainage
Rock fill areas should be tied to a subdrainage system. If conventional fill is placed that separates the rock
from the main canyon subdrain then a secondary system should be installed. A system consisting of an
adequately graded base (3 to 4 percent to the lower side) with a collector system and outlets may suffice.
Additionally, at approximately every 25 foot vertical interval, a collector system with outlets should be
placed at the interface of the rock fill and the conventional fill blanketing a fill slope
Monitorin2
Depending upon the depth of the rock fill and other factors, monitoring for settlement of the fill areas may
be needed following completion of grading. Typically, if rock fill depths exceed 40 feet, monitoring would
be recommend prior to construction of any settlement sensitive improvements. Delays of 3 to 6 months or
longer can be expected prior to the start of construction.
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 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:
shallow (12 + inches) under slab interior trenches and,
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 piace 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.
JU,
G EOT E K
Grading Guidelines APPENDIX C
Page 9
JOB SAFETY
General
Personnel safety is a primary concern on all job sites. The following summaries our 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.
Safety Meetings: Our field personnel are directed to attend the contractor's regularly scheduled
safety meetings.
Safety Vests: Safety vests are provided for and are to be worn by our personnel while on the job
site.
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, preferable 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.
G EOT E K
Grading Guidelines APPENDIX C
Page 10
TEST PIT SAFETY PLAN
ISIDE VIEW
Spoil 1T1 Te~Pft
pile
50 ft Zone of Traffic Direction 0' Non-Encroachment
Vehicle
parked here -
Test Pit
-
CE looftZoneof
44 Non-Encroachment 50ftZoneof
Non-Encroachment
PLAN VIEW
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;
I. is 5 feet or deeper unless shored or laid back,
exit points or ladders are not provide,
displays any evidence of instability, has any loose rock or other debris which could fall into the
trench, or
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.
C EOTEK
Grading Guidelines APPENDIX C
Page 11
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.
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.
G EOTEK