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PRELIMINARY GEOTECHNICAL EVALUATION
FOR
PROJECT No. 344 I -SD3
APN 203-100-0 I
MADISON STREET PROJECT
CARLSBAD, CALIFORNIA
PREPARED FOR
VESTA PACIFIC DEVELOPMENT
I 818 2"d Street
SAN DIEGO, California
PREPARED BY
GEOTEK, INC.
1384 POINSETTIA AVE, SUITE A
VISTA, CALIFORNIA 92081
GEOTEK
MAY 20, 2014
GeoTek. Inc.
138-1 Poinsettia Avenue, Suite A Vista, CA 92081-8505
(760) 599-0509 '" • • • (760) 599-0593 ' • www.geotekusa.com
Vesta Pacific Development
1818 Second Avenue
San Diego, California 920 I I
Attention:
Subject:
Mr. Geoff McComic
Preliminary Geotechnical Evaluation
APN 203-100-0 I
Madison Street Project
Carlsbad, California
Dear Mr. McComic:
May 20, 2014
Project No. 344 I -SD3
We are pleased to provide herewith the results of our preliminary geotechnical evaluation for
the subject site located in Carlsbad, California. This report presents the results of our
evaluation, discussion of our findings, and provides geotechnical recommendations for
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 .
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Respectfully submitted,
GeoTek, Inc.
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CEG 1142, Exp. 04/30/14
Principal Geologist
Distribution: (5) Addressee
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GEOTECHNICAL I ENVIRONMENTAL I MATERIALS
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad, California
TABLE OF CONTENTS
Project No. 3441-SD3
May 20, 2014
Page i
I. PURPOSE AND SCOPE OF SERVICES ............................................................................................. I
2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT .............................................................. I
2.1 SITE DESCRIPTION ................................................................................................................................................................... 1
2.2 PROPOSED DEVELOPMENT ..................................................................................................................................................... 2
3. FIELD EXPLORATION AND LABORATORY TESTING ................................................................ 2
3.1 FIELD EXPLORATION ............................................................................................................................................................... 2
3.2 LABORATORY TESTING .......................................................................................................................................................... 2
4. GEOLOGIC AND SOILS CONDITIONS ........................................................................................... 3
4.1 REGIONAL SETTING ..................................................................................................................................... : .......................... 3
4.2 GENERAL SOIL CONDITIONS ................................................................................................................................................. 4
4.3 SURFACE AND GROUNDWATER ........................................................................................................................................... 5
4.3. I Surface Water ................................................................................................................................................................................. 5
4.3.2 Groundwater .................................................................................................................................................................................... 5
4.4 FAULTING AND SEISMICITY .................................................................................................................................................... 5
4. 4.1 Seismic Design Parameters ......................................................................................................................................................... 5
4.5 LIQUEFACTION AND SEISMICALLY INDUCED SETTLEMENT ................................................................................................ 6
4.6 OTHER SEISMIC HAZARDS ..................................................................................................................................................... 7
5. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 7
5.1 GENERAL .................................................................................................................................................................................. ?
5.2 EARTHWORK CONSIDERATIONS .......................................................................................................................................... 7
5.2. I Site Clearing ..................................................................................................................................................................................... 7
5.2.2 Fills ....................................................................................................................................................................................................... 8
5.2.3 Removals ........................................................................................................................................................................................... 8
5.2.4 Excavation Characteristics ........................................................................................................................................................... 8
5.2.5 Shrinkage, Bulking, and Subsidence ......................................................................................................................................... 9
5.2.6 Import Soil ........................................................................................................................................................................................ 9
5.3 DESIGN RECOMMENDATIONS ............................................................................................................................................... 9
5.3. I Foundation Design Criteria .......................................................................................................................................................... 9
5.3.2 Underslab Compaction Recommendations .......................................................................................................................... I I •
5.3.3 Moisture and Vapor Retarding System ..................................................................................................... : ........................... 11
5.3.4 Sett/ement.. ..................................................................................................................................................................................... 12
5.3.5 Foundation Set Backs ................................................................................ : ................................................................................. 12
5.3.6 Soil Corrosivity ............................................................................................................................................................................. 12
5.3. 7 Soil Sulfate Content ..................................................................................................................................................................... 13
5.4 RETAINING WALL DESIGN AND CONSTRUCTION .......................................................................................................... 13
5.4. I General Design Criteria .............................................................................................................................................................. 13
5.4.2 Cantilevered Walls ....................................................................................................................................................................... 13
5.4.3 Wall Backfill and Drainage ....................................................................................................................................................... 14
5.4.4 Restrained Retaining Walls ....................................................................................................................................................... 15
5.5 POST CONSTRUCTION CONSIDERATIONS ....................................................................................................................... 15
5.5. I Landscape Maintenance and Planting ................................................................................................................................... 15
5.5.2 Drainage .......................................................................................................................................................................................... 15
5.6 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS ................................................................................................... 16
GEOTEK
C
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I , Carlsbad, California
• TABLE OF CONTENTS
Project No. 344 I -SD3
May 20, 2014
Page ii
6. INTENT ............................................................................................................................................... 16
7. LIMITATIONS .................................................................................................................................... 17
8. SELECTED REFERENCES ................................................................................................................. 17
ENCLOSURES
Figure I -Site Location Map
Figure 2 -Site Explorations Map
Figure 3 -Regional Geologic Map
Appendix A -Grading Guidelines
A
GliOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
. 'Project No. 344I-5D3
May 20, 2014
Page I
I. PURPOSE AND SCOPE OF SERVICES
The purpose of this study was to evaluate the geotechnical conditions in the area of proposed
construction. Services provided for this study included the following:
► Research and review of available geologic data and general information pertinent to the
site,
► Site exploration consisting of the excavation, logging, and sampling of three (3) exploratory
borings,
► Laboratory testing of soil samples collected during the field investigati~n.
► Review and evaluation of site seismicity,
► Geologic and engineering analysis of data obtained, and
► Compilation of this geotechnical report which presents our findings, conclusions, and
recommendations for site development.
2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT
2.1 SITE DESCRIPTION
The site, which apparently does not have a postal address, is located between 2646 and 2710
Madison Street, Carlsbad, California, 92008 (see Figure I -Site Location Map). The property
appears to be rectangular elongated northeast to southwest (perpendicular to Madison). It
consists of approximately 13,000 square feet of gently sloping terrain with the exception of an
apparent cut slope about three (3) feet high along Madison Street. There is a rough drive
access from the street in the central portion of the site. The property slopes toward the
street. The site is elevated about three (3) to four (4) feet above Madison. The site is currently
fenced and vacant. Surface drainage on the site appears to be directed to the street.
The subject site is bounded by older developed sites both multi-and single-family residential
properties and Madison to the southwest.
GEOTEK
C
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
2.2 PROPOSED DEVELOPMENT
Project No. 344 l-5D3
May 20, 2014
Page 2
No site plan has been provided. It is our understanding that proposed development consists of
multi-family residential. Considering the elevation of the site above street grade, it seems likely
that the site may be lowered to achieve final grades with retaining wall used to support
perimeter cuts. Retaining walls may be integrated .into the structure(s) or be independent site
walls. It appears the walls will not likely exceed six (6) feet in height.
We anticipate that conventionally reinforced slab-on-grade with spread and continuous wall
footings would be used to support the relatively lightweight framed structure. Structural loads
are anticipated to be typical for this type of construction, with wall loads not exceeding 3000
pounds per lineal foot and isolated columns loads not exceeding 30 kips.
If site development differs from that described above, the recommendations included in this
report should be subject to further review and evaluation.
3. FIELD EXPLORATION AND LABORATORYTESTING
3.1 FIELD EXPLORATION
Field exploration was conducted on February 24, 2014 and consisted of excavating three (3)
exploratory borings with a manual auger to a maximum depth of approximately 4.5 feet. A
representative from our firm logged the excavations and collected samples for use in the
laboratory testing. The logs of exp!oratory borings and the approximate boring locations are
shown on Figure 2 -Site Explorations Map.
3.2 LABORATORY TESTING
Laboratory testing was performed on selected soil samples collected during the field
exploration. The purpose of the laboratory testing was to confirm the field classification of the
soil materials encountered and to evaluate their physical properties for use in the engineering
design and analysis. Results of the laboratory testing program, along with a brief description
and relevant information regarding testing procedures are presented below.
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I . Carlsbad. California
Expansion Index
..
Project No. 3441-SDJ
May 20, 2014
Page 3
Expansion Index testing was performed on a soil sample. Testing was performed in general
accordance with ASTM Test Method D 4829. The Expansion Index (El) test was less than 5
which indicates a very low expansion potential. It is not considered as expansive per the 2013
CBC Section 1803.5.3.
Moisture-Density Relations
Laboratory testing was performed on a sample considere_d reasonably representative of the
dominant soil type encountered during the subsurface exploration. A laboratory maximum dry
density of 125 pcf at optimum moisture content of 8.5% was determined in general accordance
with test method ASTM D1557.
Chemical Analysis
Chemical analyses as indicated below were performed by our subcontractor. Tests results are
enclosed.
Sulfate Content
Analysis to determine the water-soluble sulfate content was performed by others in general
accordance with California Test No. 417. Results of the testing indicated a 0.0 18% by weight
sulfate content, which is considered "not applicable" (negligible) as per Table 4.2.1 of ACI 318.
Resistivity and pH
A representative soil sample was tested by others for resistivity and pH in general accordance
with California Test 643. The results of the testing are included herein indicate a resistivity of
3400 ohms-cm and a pH of 7.35.
Chloride
Analysis to determine the chloride content was performed by others in general accordance
with California Test No. 422. Results of the testing indicated I 02ppm.
4. GEOLOGIC AND SOILS CONDITIONS
4.1 REGIONAL SETTING
The project is situated in the Peninsular Ranges Geomorphic Province. This province
encompasses an area that extends approximately 900 miles from the Transverse Ranges south
to the tip of Baja California, and varies in width from roughly 30 to I 00 miles. The province is
characterized by mountainous terrain in the east comprised dominantly of Mesozoic igneous
GEOTEK
C
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
Project No. 344 I -S03
May 20, 2014
Page 4
and metamorphic rocks, with relatively low-lying coastal terraces to the west underlain by late
Cretaceous, Tertiary, and Quaternary age sedimentary bedrock.
The Peninsular Ranges are traversed by several major active faults. The Newport-Inglewood
Rose Canyon, Whittier-Elsinore, San Jacinto, and San Andreas faults are major active fault
systems located north-northeast of the site and the Rose Canyon, Coronado Bank, and San
Diego Trough are active faults located to the west. Major tectonic activity associated with
these and other faults within this regional tectonic framework is marked by right-lateral and
strike-slip movement.
The province is characterized by major mountain ranges with intervening alluviated, broadly
synclinal valleys and narrow stream canyons. The province subdivides into several individual
ranges and geologic features. The major subdivisions .of interest are the Santa Ynez Mountains,
Central Ventura County Mountains, Santa Monica Mountains, Ventura/Soledad Basin, Ridge
Basin, San Gabriel Mountains, Los Angeles Basin, San Bernardino Mountains, and the Eastern
Boundary Ranges.
While the underlying geology of northern San Diego County is rather complex, in the more
immediate area of coastal north county much of the near shore terraced geomorphology is
underlain Paralic Deposits. Regional geologic mapping by Kennedy and Tan, 2005 (see Figure 3
-Regional Geologic Map) indicates this immediate area is underlain by a deposit designated as
Qop 6-7 which are relatively recent deposits.
4.2 GENERAL SOIL CONDITIONS
A brief description of the earth materials encountered is presented in the following sections.
The subsurface profile at this site consists of Quaternary old paralic deposits (see Figure 3 -
Regional Geologic Map).
Quaternary-aged old paralic deposits (formerly referred to as terrace deposits) underlie the
site at depth and generally consist of massively bedded, weakly to slightly cemented, medium
dense, sands. Approximately the upper two (2) feet silty and loose due to weathering.
A
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I . Carlsbad. California
4.3 SURFACE AND GROUNDWATER
4.3.1 Surface Water
Project No. 344 l-5D3
May 20, 2014
Page 5
If encountered during the earthwork construction, surface water on this site is the result of
precipitation or surface run-off from surrounding site primarily to the northeast. Area
drainage is generally directed to the west. Provisions for surface drainage will need to be
accounted for by the project civil engineer, if necessary.
4.3.2 Groundwater
Groundwater was not encountered in our exploratory excavations. The site is approximately
50 feet above sea level and given the proximity to the ocean the groundwater level is probably
at least 40 feet below the surface. No natural groundwater condition is known to be present
which would impact site development. However, groundwater or localized seepage can occur
due to variations in rainfall, irrigation practices, and other factors not evident at the time of
this evaluation.
4.4 FAUL TING AND SEISMICITY
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. The site is not
situated within an "Alquist-Priolo" Earthquake Fault Zone, or·a State of California Special Studies
Zone, or any City designated zone.
4.4.1 Seismic Design Parameters
The site is located at approximately 32.1644 Latitude and -1 17.3490 Longitude. Site spectral
accelerations (Ss and SI), for 0.2 and 1.0 second periods for a risk targeted one (I) percent
probability of exceedance in 50 years (MCER) were determined from the USGS
Earthquake Hazards Program, U.S. Seismic Design Maps Website
(http://earthquake.usgs.gov/designmaps/us/application.php). The site is considered a Site Class
"C", due the shallow paralic deposit. The results are presented in the following table:
GEOTEK
C
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-1 00-0 I . Carlsbad, California
Table 4.4 -SITE SEISMIC PARAMETERS
Mapped 0.2 sec Period Spectral Acceleration, Ss (g)
Mapped 1.0 sec Period Spectral Acceleration, SI (g)
Maximum Considered Earthquake Spectral Response Acceleration
Parameter at 0.2 Second, SMS (g)
Maximum Considered Earthquake Spectral Response Acceleration
Parameter at 1.0 second, SM I (g)
Design Spectral Response Acceleration Parameter for 0.2 Second, SDS (g)
Design Spectral Response Acceleration Parameter for 1.0 Second, SD I (g)
Site Coefficient, Fa
Site Coefficient, Fv
Project No. 3441-5D3
May 20, 2014
Pa2e 6
1.151
0.441
1.151
0.599
0.767
0.400
1.00
1.359
Seismically resistant structural design in accordance with applicable code should be followed
during the design of the structure. The California Building Code (CBC) has been developed to
reduce the potential for structural damage. However, some level of damage as the result of
ground shaking generated by nearby earthquakes is considered likely in this general area.
4.5 LIQUEFACTION AND SEISMICALLY INDUCED SETTLEMENT
Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake-
induced ground motion, create excess pore pressures in relatively cohesion less soils. These
soils may thereby acquire a high ~egree of mobility, which can lead to lateral movement,
sliding, consolidation and settlement of loose sediments, sand boils and other damaging
cieformations. This phenomenon occurs only below the water table, but, after liquefaction has
developed, it can propagate upward into overlying non-saturated soil as excess pore water
dissipates.
The factors known to influence liquefaction potential include soil type and grain size, relative
density, groundwater level, confining pressures, and both intensity and duration of ground
shaking. In general, materials that are susceptible to liquefaction are loose, saturated granular
soils having low fines content under low confining pressures.
The City of Carlsbad General Plan does not indicate the site is in a liquefaction study area.
The liquefaction potential on the site is considered negligible due to the relatively dense nature
of the underlying materials at the depths explored and expected depths to groundwater.
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
4.6 OTHER SEISMIC HAZARDS
Project No. "344 I -SD3
May 20, 2014
Page 7
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 are considered to be
negligible due to site elevation and distance from an open body of water.
5. CONCLUSIONSAND RECOMMENDATIONS
5.1 GENERAL
The proposed site development appears feasible from a geotechnical viewpoint provided that
the following recommendations are incorporated into the design and construction phases of
development.
Geotechnical conditions do not appear to represent significant constraints on site
development. If the site is cut to grade and finish grades are more than 2.5 feet below the
existing ground surface then no corrective grading is anticipated.
5.2 EARTHWORK CONSIDERATIONS
Earthwork and grading should be performed in accordance with the applicable grading
ordinances of City of Carlsbad, the 2013 California Building Code (CBC), and
recommendations contained in this report. Appendix A -Grading Guidelines included in
outline general procedures and do not anticipate all site specific situations. In the event of
conflict, the recommendations presented in the text of this report should supersede those
contained in Appendix A
5.2.1 Site Clearing
The site will need to be cleared including any debris present. Care should be taken during site
grading to check for any buried foundations, vegetation, roots, trash and debris, and properly
dispose of these materials offsite. While it appears the site has never been developed it is not
uncommon to find extensions of defunct septic systems from adjacent sites in older areas such
as this. If something of this nature is present on the site, it would require removal. Areas of
loose soil, root systems or other undesirable items may be encountered. Any holes resulting
from site clearing, tree removal, etc. should be observed by the project geotechnical consultant
A
GEOTEK
C
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I, Carlsbad, California
Project No. 3441-SDJ
May 20, 2014
Pa2e 8
prior to filling. The voids should be filled with properly compacted fill materials with expansion
characteristics similar to the existing onsite soils.
5.2.2 Fills
The onsite soils are considered suitable for reuse as engineered fill provided they are free from
vegetation, debris and other deleterious material. Undercut areas should be brought to final
subgrade elevations with fill materials placed and compacted. Soil should be moisture
conditioned to at least optimum moisture content and compacted to a minimum of 90%
relative compaction per ASTM Test Designation 155 7 in accordance with the general grading
guidelines presented in Appendix A.
5.2.3 Removals
The need for removals will depend largely on the finish site grades. If grades are lowered by at
2.5 feet then it is likely that reasonably uniform paralic deposits would be encountered, no
additional removal would be anticipated. Otherwise removals should be adequate to remove
loose or disturbed soil and to provide a minimum of two (2) feet of engineered fill beneath the
building footings. Removal should also be sufficient to assess that all footing, utilities, etc.
associated with any prior development are removed.
Removals in the parking area should remove any loose material present and provide a
minimum of 12 inches of engineered fill below the subgrade elevation.
Depending on actual field conditions encountered during grading, locally deeper areas of
removal may be recommended. The bottom of all removals should be scarified to an
approximate depth of eight (8) inches, brought to at or above optimum moisture content, and
then recompacted to minimum project standards prior to fill placement.
Care sholJld be taken during removals to protect adjoining improvements. It may be necessary
to excavate small sections adjacent to the retaining walls on the adjoining properties.
5.2.4 Excavation Characteristics
Excavation in the onsite materials is expected to be easy using moderate to heavy-duty grading
equipment in good operating condi~ions. All temporary excavations for grading purposes and
installation of underground utilities should be constructed in accordance with local and Cal-
OSHA guidelines. Temporary excavations within the onsite materials are anticipated to be
stable at I: I inclinations for cuts less than seven (7) feet in height.
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California .
5.2.5 Shrinkage, Bulking, and Subsidence
Project No. 344 I-SD3
May 20, 2014
Page 9
Several factors will impact earthwork balancing on the site, including shrinkage, bulking,
subsidence, trench spoil from utilities and footing excavations, as well as the accuracy of
topography.
Shrinkage, bulking and subsidence are primarily dependent upon the degree of compactive
effort achieved during construction. Considering the size of the site and likelihood of export
shrinkage is not considered a significant factor. Subsidence and bulking are not considered to
be a factor with the underlying materials within the vicinity of the proposed construction.
5.2.6 Import Soil
If import soil is needed, preferably it should be similar to site-soils and have an Expansion Index
(El) of 20 or less. It is recommended that import source(s) be sampled and tested by GeoTek
at least 72 hours prior to import onto the site. Test results can then be discussed with client,
who can determine whether the materials are acceptable to them.
5.3 DESIGN RECOMMENDATIONS
5.3.1 Foundation Design Criteria
Preliminary foundation design criteria for a conventional foundation system, in general
conformance with the 2013 CBC, are presented herein. These are typical design criteria anci
are not intended to supersede the design by the structural engineer. We have assumed that
foundations will support a minimum of two floors.
Soils encountered in borings are not considered to be expansive per the CBC. Below are
preliminary foundation recommendations assuming El S 20. If more expansive soil is placed
beneath the foundations then modified recommendations would be required. Additional
laboratory testing should be performed at the completion of site grading to verify the
expansion potential of the subgrade soils.
A summary of our preliminary foundation design recommendations are presented in Table
6.3.1 below:
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad, California
Project No. 3441-5D3
May 20, 2014
Page 10
TABLE 6.3.I -MINIMUM DESIGN REQUIREMENTS
DESIGN PARAMETER O<El~20 & Pl< I 0
Foundation Depth or Minimum Perimeter Beam Supporting Two Floors -18
Depth (inches below lowest adjacent grade) Supporting Three Floors -24
Foundation Width (lnchei;) Supporting Two Floors -15
Supporting Three Floors -18
Minimum Slab Thickness (inches) 4 (actual)
Minimum Slab Reinforcing No. 3 rebar 24" on-center,
placed in middle third of slab
Minimum Footing Reinforcement Two (2) No. 4 Reinforcing Bars
One (I) top and one (I) bottom
Presaturation of Subgrade Soil I 00%/ I 2 inches (Percent of Optimum/Depth in Inches)
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 criteria for design of foundations should be implemented into design:
5.3.1.1 An allowable bearing capacity of 2000 pounds per square foot (psf) may be used for
design of continuous and perimeter footings 18 inches deep and 15 inches wide, and
pad footings 24 inches square and 24 inches deep. This value may be increased by 200
pounds per square foot far each additional 12 inches in depth and I 00 pounds per
square foot for each additional 12 inches in width to a maximum value of 3,000 psf.
Additionally, an increase of one-third may be applied when considering short-term live
loads (e.g. seismic and wind loads).
5.3.1.2 The passive earth pressure may be computed as an equivalent fluid having a density of
150 psf per foot of depth, to a maximum earth pressure of 2,000 psf for footings
founded on compacted fill. A coefficient of friction between soil and concrete of 0.25
may be used with dead load forces. The upper one foot of soil below the adjacent
grade should not be used in calculating passive pressure. When combining passive
pressure and frictional resistance, the passive pressure component should be reduced
by one-third.
5.3.1.3 A grade beam, 12 inches wide by 18 inches deep (minimum), should be utilized across
large opening or garage entrances. The base of the grade beam should be at the same
elevation as the bottom of the adjoining footings.
5.3.1 .4 Isolated exterior footings should be tied back to the main foundation system in at least
one direction.
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
Project No. 344 I-S03
May 20, 2014
Pai:e II
5.3.1.5 Footing excavations should be free of loose/sloughed materials and be neatly trimmed
at the time of concrete placement.
5.3.1.6 It should be noted that considering the sandy nature of the soil footing and other
excavations may have a tendancy to slough particularly as the soil dries.
5.3.1.7 All loose material should be removed from footing prior to pouring concrete. It is
likely that this will result in additional concrete being needed.
5.3.1.8 If sides of footings are blocked out or formed to limit concrete over-pour then any
adjoining void should be properly backfilled after concrete is allowed to cure.
5.3.2 Underslab Compaction Recommendations
5.3.2.1 To minimize moisture penetration beneath the slab on grade areas, utility trenches
should be backfilled with engineered fill, lean concrete or concrete slurry where they
intercept the perimeter footing or thickened slab edge.
5.3.2.2 Soils from the footing excavations should not be placed in the slab-on-grade areas
unless properly compacted and tested.
5.3.2.3 Under-slab utility trenches should be compacted to project specifications.
Compaction should be achieved with a mechanical compaction device. If backfill soils
have dried out, they should be thoroughly moisture conditioned prior to placement in
trenches.
5.3.2.4 Utility trench excavations should be shored or laid back in accordance with applicable
CAL/OSHA standards.
5.3.2.5 On-site materials may not be suitable for use as bedding material, but will be suitable
as backfill. Jetting of native soils will not be acceptable.
5.3.3 Moisture and Vapor Retarding System
A moisture and vapor retarding system should be placed below slabs-on-grade where moisture
migration through the slab is undesirable. As a minimum, the capillary break and moisture
retarder should be in conformance with the 2013 CBC Section 1910.1 or, if adopted by the
local agency, the 20 IO California Green Building Standards Code (CALGreen) Section 4.505.2.
It should be realized that the effectiveness of the vapor retarding membrane can be adversely
impacted as the result of construction related punctures (e.g. stake penetrations, tears,
punctures from walking on the aggregate layer, etc.). These occurrences should be limited as
much as possible during construction. Thicker membranes are generally more puncture
resistant than thinner ones. Products specifically designed for use as moisture/vapor retarders
may also be more puncture resistant. It is GeoTek's opinion that a minimum 10 mil thick
membrane with joints properly overlapped and sealed should be used.
GEOTEK
C
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
Project No. 3441-5D3
May 20, 2014
Page 12
Moisture and vapor retarding systems constructed in compliance with Code minimums 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. 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 permeance) to achieve the desired
performance level. Consideration should be given to consulting with an individual possessing
specific expertise in this area for additional evaluation.
5.3.4 Settlement
The anticipated total and differential settlements are estimated less than I inch and I /2 inch
over 40 feet of horizontal distance, respectively.
5.3.5 Foundation Set Backs
Minimum setbacks to all foundations should comply with the 2013 CBC. Any improvements
not conforming to these setbacks may be subject to lateral movements and/or differential
settlements:
♦ The outside bottom edge of all footings should be set back a minimum of H/3 (where H
is the slope height) from the face of any descending slope. The setback should be at
least 7 feet and need not exceed 40 feet.
♦ 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.
♦ 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.
♦ Structures should be setback a minimum of H/3 to a maximum of 15 feet from any
ascending slope, unless specifically reviewed and otherwise found acceptable.
5.3.6 Soil Corrosivity
The soil resistivity at this site was tE:sted in the laboratory on representative samples collected
during the field investigation. The results of the testing indicate that the onsite soils are
considered "moderately corrosive" to buried metal in accordance with current standards
commonly used by corrosion engineers. These characteristics are considered typical of soils
commonly found in southern California. We recommend that a corrosion engineer be
consulted to provide recommendations for proper protection of buried metal at this site.
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I , Carlsbad, California
5.3.7 Soil Sulfate Content
R ....
Project No. 344 I -SD3
May 20, 2014
Page 13
The sulfate content was determined in the laboratory for a representative onsite soil sample.
The results indicate that the water soluble sulfate range is 0.0 i 8 percent by weight, which is
considered "not applicable" (i.e. negligible) as per Table 4.2.1 of ACI 318. Concrete mix design
may be selected accordingly.
5.4 RETAINING WALL DESIGN AND CONSTRUCTION
5.4.1 General Design Criteria
Recommendations presented herein may apply to typical masonry or concrete vertical
retaining walls to a maximum height of up to 6 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
paralic deposits should be designed using an allowable bearing capacity of 2,000 psf. An
increase of one-third may be applied when considering short-term live loads (e.g. seismic and
wind loads). Bearing capacity may be increased by 200 psf for each additional foot of width or
depth to a maximum of 3,000 psf. The passive earth press_ure may be computed as an
equivalent fluid having a density of 200 psf per foot of depth, to a maximum earth pressure of
2,500 psf. A coefficient of friction between soil and concrete of 0. 3 may be used with dead
load forces. The upper one foot of soil below the adjacent grade should not be used in
calculating passive pressure. When combining passive pressure and frictional resistance, the
passive pressure component should be reduced by one-third.
5.4.2 Cantilevered Walls
The recommendations presented below are for cantilevered retaining walls up to 6 feet high.
Active earth pressure may be used for retaining wall design, provided the top of the wall is not
restrained from minor deflections. An equivalent fluid pressure approach may be used to
compute the horizontal pressure against the wall. Appropriate fluid unit weights are given
below for specific slope gradients of the retained material. These do not include other
superimposed loading conditions such as traffic, structures, seismic events, or adverse geologic
conditions.
GEOTEK
C
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
Project No. 3441-SD3
May 20, 2014
Page 14
TABLE 6.4.2 -ACTIVE EARTH PRESSURES
Surface Slope of Retained Materials Equivalent Fluid Pressure Equivalent Fluid Pressure
(H:V) (PCF) (PCF)
Select Backfill* Native Backfill
Level 35 35
2:1 50 50
* Select backfill may consist of Class 2 permeable filter materials, Class 2 aggregate base or imported Sand
with an SE>30. Backfill zone includes area between back of wall to plane (1:1, h:v) up from back of wall
foundation to ground surface.
5.4.3 Wall Backfill and Drainage
Wall backfill should include a minimum one 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. 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
at 90% relative compaction in accordance with ASTM Test Method D 1557. Proper surface
drainage needs to be provided and maintained.
Retaining walls should be provided with an adequate pipe and gravel backdrain system to
prevent build up of hydrostatic pressures. Backdrains should consist of a 4-inch diameter
perforated collector pipe (Schedule 40 PVC, SDR 35, or approved equivalent) embedded in a
minimum of one cubic foot per lineal foot of 3/4 to one inch clean crushed rock or equivalent,
wrapped in filter fabric. Panel drains may be used as an alternative. The drain system should
be connected to a suitable outlet. A minimum of two outlets should be provided for each
drain section. Spacing betw,een drain outlets should not exceed I 00 feet.
Walls from 2 to 4 feet in height may be drained using localized gravel packs behind weep holes
at IO feet maximum spacing (e.g. approximately 1.5 cubic feet of gravel in a woven plastic bag).
Weep holes should be provided or the head joints omitted in the first course of block
extended above the ground surface. However, nuisance water may still collect in front of the
wall.
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
5.4.4 Restl"'ained Retaining Walls
Project No . .344 I -SD3
May 20, 2014
Page 15
Any retaining walls that will be restrained prior to placing and compacting backfill material or
that have reentrant or male corners, should be designed for an at-rest equivalent fluid pressure
of 65 pd, plus any applicable surcharge loading. For areas of male or reentrant corners, the
restrained wall design should extend a minimum distance of twice the height of the wall
laterally from the corner.
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 fror.n 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 decrease 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 Dl"'ainage
The need to maintain proper surface drainage and subsurface systems cannot be overly
emphasized. Positive site drainage should be maintained at all times. Drainage should not fl ow
uncontrolled down any descending slope. Water should be directed away from foundations
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I, Carlsbad, California
Project No. 3441-SD3
May 20, 2014
Page 16
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.
5.6 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS
We recommend that site grading, specifications, and foundation plans be reviewed by this
office prior to construction to check for conformance with the recommendations of this
report. 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 representatives perform at
least the following duties:
• Observe site clearing and grubbing operations for proper removal of all 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 where necessary.
• Observe the fill for uniformity during placement including utility trenches. Also, test the fill
for field density and relative compaction.
• Observe and probe foundation materials to confirm suitability of bearing materials.
If requested, a construction observation and compaction report can be provided by Geo T ek,
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. INTENT
It is the intent of this report to aid in the design and construction of the proposed
development. Implementation of the advice presented in Section 6 of this report is intended
to reduce risk associated with construction projects. The professional opinions and
geotechnical advice contained in this report are not intended to imply total performance of the
A
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I, Carlsbad, California
Project No. 344 l-5D3
May 20, 2014
Page 17
project or guarantee that unusual or variable conditions will not be discovered during or after
construction.
The scope of our evaluation is limited to the area explored within the boundaries of the
subject residential lot and as shown on the enclosed Site Explorations Map (Figure 2). This
evaluation does not and should in no way be construed to encompass any areas beyond the
specific area of the 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 (P3-0300 I I 2SD dated March
29, 2012) and geotechnical engineering standards normally used on similar projects in this
region.
7. LIMITATIONS
The materials observed on the project site appear to be representative of the area; however,
soil and bedrock materials vary in character between excavations and natural outcrops or
conditions exposed during site construction. Site conditions may vary due to seasonal changes
or other factors. Geo T ek, Inc. assumes no responsibility or liability for work, testing or
recommendations performed or provided by others.
Since our recommendations are based on the site conditions observed and encountered, and
laboratory testing, our conclusion and recommendations are professional opinions that are
limited to the extent of the available data. Observations during construction are important to
allow for any change in recommendations found to be warranted. These opinions have been
derived in accordance with current standards of practice and no warranty is expressed or
implied. Standards of practice are subject to change with time.
8. SELECTED REFERENCES
ASTM, 20 I I, "Soil and Rock: American Society for Testing and Materials," volumes 4.08 and
4.09.
California Code of Regulations, Title 24, 2013 "California Building Code,"
California Department of Water Resources groundwater well data (http://wdl.water.ca.gov).
GeoTek, Inc., In-house proprietary information.
A
GEOTEK
Vesta Pacific Development
Preliminary Geotechnical Evaluation
APN 203-100-0 I. Carlsbad. California
Project No. 344 l-5D3
May 20, 2014
Page 18
USGS, ·Earthquake Hazards Program, U.S. Seismic Design Maps Website
(http://earthquake.usgs.gov/designmaps/us/application.php).
City Carlsbad General Plan, obtained on City Carlsbad Web Site
(http://www.carlsbadca.gov/services/departments/planning/pages/general-plan.aspx)
GEOTEK
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1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505
May 2014
'-=-=-JOOOIHI O ?lfl IOOOMUlllS
l'nntod from TOPO! e:w1 H11ioMl Ot<JC161)1uc Ho~ (WWW topo com)
Site Exploration Plan
Madison Street Site
Carlsbad, California
Figure 1
Boring B-1
O -2' Topsoil: Dark reddish brown,
loose, slightly moist, slightly silty Sand
2 -3.5 • Grey, medium dense, slightly
moist, fine to medium grained, Sand
Practical Refusal
Total depth 4.5'
gf t: earth <..
Locations are approximate
PN: 3441-SDJ
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505
May 2014
Boring B-2 Boring B-3
0 -2' Topsoil: Dark reddish brown, 0 -2' Topsoil: Dark reddish brown,
loose, slightly moist, slightly silty Sand loose, slightly moist, slightly silty Sand
2 -3.5 • Red brown, medium dense, 2 -3.5 • Red brown, medium dense,
slightly moist, fine to medium grained, slightly moist, fine to medium grained,
Sand Sand
Total depth 4.5' Total depth 4.5'
100
40
Site Exploration Plan
Madison Street Project
Carlsbad, California
Figure 2
Not to scale
'il
GFOTFK
PN: 3441-SDJ
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505
May 20/4
From: Geologic Map Of The Oceanside 30' X 60' Quadrangle,
California" Compiled by Michael P. Kennedy and Slang S. Tan,
2005, published by. U.S. Geological Survey.
Regional Geologic Map
Madison Street
Carlsbad, California
Figure 3
APPENDIX A
Grading Guidelines
Madison Street
APN 203-1 00-0 I
Carlsbad, California
Project No. 3441-SDl
G E OT E K
EARTHWORK GRADING GUIDELINES
EARTHWORK GRADING GUIDELINES
APPENDIX A
Page I
Site grading should be performed to at least the minim~m requirements of the governing
agencies, the 2013 California Building Code and the guidelines presented below.
Site Clearin2
Trees, dense vegetation, and other deleterious materials should be removed from the site.
Non organic debris or concrete may be placed in deeper fill areas per the recommendations
of the Soils Engineer.
Prudent efforts should be made by the contractor to remove all organic or other
deleterious material from the fill. This is especially important when grading is occurring near
the natural grade. All operators should be aware of these efforts. Even the most diligent
efforts may result in the incorporation of some materials. Laborers may be required as
"root pickers".
Subdraina2e
Subdrains are not anticipated in conjunction with the proposed grading. Should conditions
be encountered necessitating subdrain placement, specific recommendations will be offered.
Treatment of Existine Ground
Vegetation, rubbish and other deleterious materials should be disposed of off site.
Loose and compressible materials (including weathered rock, deposits of alluvium and
colluvium, poorly compacted or weathered fill, etc.) should be removed unless otherwise
indicated in the text of this report. Deeper removals than indicated in the text of the
report may be necessary due to saturation during winter months, as the result of changes
over time or due to variations in the subsurface.
Subsequent to removals, the ground surface should be processed to a depth of eight (8)
inches, moistened to near optimum moisture conditions and compacted to fill standards.
Exploratory test excavations (backhoe or dozer trenches) still remaining after completion of
basic removals should be excavated and filled with compacted fill if they can be located.
Fill Placement
It should be realized that proper fill compaction is largely procedural and is the responsibility
of the grading contractor. Testing and observation by the Soil Engineer, while helpful to
EARTHWORK GRADING GUIDELINES APPENDIX A
Page 2
evaluate the efforts of the contractor, should not be considered as a substitute for proper
and consistent procedures. Compaction testing is specific to the test location; variable test
results could be obtained in other locations. Technicians typically do not see all that occurs
during construction. Deviation from the procedures found to produce adequate test results
might result in inadequate compactive efforts .. The need for properly maintained equipment
and trained personnel operating it, cannot be over emphasized.
On site soil and bedrock may typically be used for compacted fill; however, some special
processing, placement or handling may be required (see report).
Material used in the compacting process should be evenly spread, moisture conditioned,
processed, and compacted in thin lifts not to exceed six (6) inches in thickness to obtain a
uniformly dense layer. The fill should be placed and compacted in nearly horizontal layers,
unless otherwise found acceptable by the Soils Engineer.
If the moisture content or relative density varies from that acceptable to the Soils Engineer,
the Contractor should rework the fill until it is in accordance with the following:
Moisture content of the fill should typically 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.
Each six (6) inch layer should be compacted to at least 90 percent of the maximum density
in compliance with the testing method specified by the controlling governmental agency. In
this case, the testing method is ASTM Test Designation D-1557.
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. As the fill is elevated, it should
be benched through surficial soil and slopewash and into competent bedrock or other
material deemed suitable by the Soils Engineer.
Rock fragments less than eight (8) inches in diameter may be utilized in the fill, provided:
I. They are not placed in concentrated pockets;
2. There is a sufficient percentage of fine-grained material to surround the rocks;
3. The distribution of the rocks is observed by and acceptable to the Soils Engineer.
Rocks greater than eight (8) inches in diameter should be taken off site, or placed in
accordance with the recommendations of the Soils Engineer in areas designated as suitable
for rock disposal.
EARTHWORK GRADING GUIDELINES APPENDIX A
Page 3
In clay soil 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 the up blocks.
The Contractor should be required to 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 di~ect compaction of the slope face
with suitable equipment. Given the low height of slopes on this project overbuilding the
slope and cutting back to the compacted core is recommended. Other methods should be
discussed with and accepted by this firm prior to implementing.
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.
This will generally result in the cut-fill catch point or daylight line being at least several feet
lower than the elevation indicated on the plans.
A key at least one (I) equipment width wide and wide enough to accommodate the method
of compaction used should be excavated into competent materials and observed by the soils
engineer or his representative. The key should be tilted into slope with the heel being at
least I foot lower in elevation than the toe.
The cut portion of the slope should be roughed out leaving the slope about three (3) feet
"fat", to evaluate if stabilization of the cut section is necessary. If the contractor decides to
place the fill prior to cut excavation, then he should be responsible for any additional
earthwork created by the fill placement and due to the need to stabilize the cut portion of
the slope.
Transition lots (cut and fill) and lots above stabilization fills should be capped with a
minimum three (3) foot thick compacted fill blanket. Deeper overexcavation may be
recommended in some cases.
Cut pads should be observed by the Engineering Geologist 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 (3)
feet. Deeper overexcavation may be recommended in some cases.
In cut areas exploratory test excavations (backhoe or dozer trenches) remaining after
completion of cut excavation and removal of all surficial soils and weathered rock materials
should be excavated and filled with compacted fill if they can be located. Treatment of
borings can be determined during construction.
,,,.....
~
EARTHWORK GRADING GUIDELINES
Grading Observation and-Testing
APPENDIX A
Page 4
Observation of the fill placement should be provided by the Soils Engineer during the
progress of grading.
In general, density tests would be made at intervals not exceeding two (2) feet of fill height
or every 1,000 cubic yards of fill placed. These criteria will vary depending on soil
conditions and the size of the fill.
In any event, an adequate number of field density tests should be made to evaluate if the
compactive efforts used by the contractor are such that the required compaction and
moisture content is generally being obtained.
As proper fill compaction is largely procedural, adequate test results should not be
considered as a substitute for proper procedures. This testing is, by its nature, specific to
the test location. Variable test results could be obtained in other locations.
Density tests may be made on the surface material to receive fill, as required by the Soils
Engineer.
Cleanouts, processed ground to receive fill, key excavations, subdrains and rock disposal
areas / procedures should be observed by the Soils Engineer prior to placing any fill. It will
be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for
observation.
An Engineering Geologist should observe subdrain construction.
An Engineering Geologist should observe benching prior to and during placement of fill.
10B SAFETY
General:
Job safety is of primary concern. The following outlines safety considerations for use by all
employees on multi-employer construction sites. On ground personnel are at highest risk of
injury and possible fatality on grading 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 as~ociated with geotechnical testing and observation, the
following precautions are to be implemented for the safety of our field personnel on grading
and construction projects.
EARTHWORK GRADING GUIDELINES APPENDIX A
Page 5
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 where
necessary.
Safety Flags: Two safety flags are provided to our field technician; 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 our personnel do not follow the above, we request that the contractor
contact 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 e~tablished
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 driveable condition. Alternatively, the contractor
may opt to park a piece of equipment in front of the test pits, particularly in small fill areas
or those with limited access.
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.
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 in writing. If the condition is not
rectified, the technician is required, by company policy, to immediately withdraw and notify
their supervisor. The grading contractor representative will then be contacted in an effort
to effect a solution. No further testing will be performed until the situation is rectified. Any
EARTHWORK GRADING GUIDELINES APPENDIX A
Page 6
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, or if the contractor feels the technician, in any way, acts in an unsafe
manner, we request that the contractor bring this to the technicians attention and if not
rectified, notify the project manager or our 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 the equipment operators of these safety
procedures particularly the zone of non-encroachment.
Trench Safety:
It is the contractor's responsibility to provide safe access into trenches where compaction
testing is needed. Our personnel are directed not to enter any excavation which:
I. is 5 feet or deeper unless shored or laid back,
2. displays any evidence of instability, has any loose rock or other debris which could
fall into the trench, or
3. displays any other evidence of any unsafe conditions regardless of depth.
All 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.
If the contractor fails to provide safe access to trenches for compaction testing, our
company policy requires that the soil technician withdraw and notify 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 could be subject to reprocessing
and/or removal.