HomeMy WebLinkAboutCT 04-22; OCEAN ESTATES; PRELIMINARY GEOTECHNICAL EVALUATION; 2003-12-03PRELIMINARY GEOTECHNICAL EVALUATION
PROPOSED OCEAN VISTA
APN 203-144-01-00, OCEAN STREET
OCEANSIDE, SAN DIEGO COUNTY, CALIFORNIA
FOR
MR. BERNARD GOLDSTEIN
160 J AMARAGK DRIVE
Geotechnical • Geologic • Environmental
RECEIVED
NOV 15 2004
CITY OF CARLSBAD
PLANNING DEPT
Geotechnical • Geologic • Environmental
5741 Palmer Way • Carlsbad, California 92008 ° (760) 438-3155 @ FAX (760) 931-0915
Mr. Bernard Goldstein
160 Tamarack Drive
Carlsbad, California 92008
December 3, 2003
W.O. 4107-A-SC
Subject: Preliminary Geotechnical Evaluation, Proposed Ocean Vista,
APN 203-144-01-00, Ocean Street, Oceanside, San Diego County, California
Dear Mr. Goldstein:
In accordance with your request, GeoSoils, Inc. (GSI) has performed a preliminary
geotechnical evaluation of the subject site. The purpose of the study was to evaluate the
onsite soils and geologic conditions and their effects on the proposed site development
from a geotechnical viewpoint.
EXECUTIVE SUMMARY
Based on our review of the available data (see Appendix A), field exploration, laboratory
testing, and geologic and engineering analysis, residential development of the property
appears to be feasible from a geotechnical viewpoint, provided the recommendations
presented in the text of this report are properly incorporated into the design and construction
of the project. The most significant elements of this study are summarized below:
• The proposed development will consist of four residential structures with
basement/garage sub-floors and two additional stories above the sub-floors, as well
as underground utility improvements.
• Excavation into Quaternary-age terrace deposits will be necessary prior to
foundation construction of the basement sub-floor. In general, unsuitable soils are
on the order of ±3 to ±4 feet across a majority of the site. However, localized
deeper removals cannot be precluded. It is anticipated that the removal of
unsuitable bearing materials will be performed by default during excavation for the
garage/basement to design grades, and thus, should not adversely affect proposed
superjacent improvements.
• The expansion potential of tested onsite soils is very low. Conventional foundations
may likely be utilized for these soil conditions.
• Foundation systems should be designed to accommodate a worst-case differential
settlement of at least 1 inch in a 40-foot span.
• At the time of this report, corrosion testing results had not been received for the
subject site. An addendum report presenting those results will be provided when lab
testing is complete.
• Our evaluation indicates that proposed temporary construction slopes onsite may
generally be considered surficially unstable, and may require shoring.
Recommendations for shoring are provided herein.
• In general, and based upon the available data to date, groundwater is not expected
to be a major factor in development of the site.
• Exterior basement walls should be waterproofed. If gravel backdrains for the
basement walls are proposed, the drains should outlet via a sump pump. In lieu of
backdrains, the basement walls should be designed to withstand the increased
hydrostatic pressure.
• Our evaluation indicates that the site has a very low potential for liquefaction.
Therefore, no recommendations for mitigation are deemed necessary.
• Our evaluation indicates there are no known active faults crossing the site.
• The seismic acceleration values and design parameters provided herein should be
considered during the design of the proposed development.
• Adverse geologic features that would preclude project feasibility were not
encountered.
• The recommendations presented in this report should be incorporated into the
design and construction considerations of the project.
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pge GeoSoils, lne ..
W.O. 4107-A-SC
Page Two
The opportunity to be of service is greatly appreciated. If you have any questions
concerning this report or if we may be of further assistance, please do not hesitate to
contact the undersigned.
Donna Gooley
Project Geologist, RG ·:: r-~-
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Distribution: (2) Addressee
(3) Mr. John Beery, Architect A.I.A.
Mr. Bernard Goldstein
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W.O. 4107-A-SC
Page Three
TABLE OF CONTENTS
SCOPE OF SERVICES ................................................... 1
SITE CONDITIONS/PROPOSED DEVELOPMENT .............................. 1
SITE EXPLORATION ..................................................... 1
REGIONAL GEOLOGY ................................................... 3
SITE GEOLOGIC UNITS .................................................. 3
Topsoil/Colluvium .................................................. 3
Quaternary-age Terrace Deposits ..................................... 3
FAULTING AND REGIONAL SEISMICITY ..................................... 4
Faulting .......................................................... 4
Seismicity ....................................................... ·; 4
Seismic Shaking Parameters ......................................... 6
Seismic Hazards ................................................... 7
GROUNDWATER ........................................................ 7
LABORATORY TESTING .................................................. 8
General .......................................................... 8
Classification ...................................................... 8
Moisture-Density Relations .......................................... 8
Laboratory Standard ................................................ 8
Expansion Potential ................................................ 8
Direct Shear Test .................................................. 9
Corrosion/Sulfate Testing ............................................ 9
CONCLUSIONS ................................................. , ... : ... 9
EARTHWORK CONSTRUCTION RECOMMENDATIONS ........................ 9
General .......................................................... 9
Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O
Removals (Unsuitable Surficial Materials) .............................. 1 O
Fill Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O
Transitions/Overexcavation ......................................... 1 O
Temporary Construction Slopes ..................................... 11
Shoring ......................................................... 11
General ................................................... 11
Lateral Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Design of Soldier Piles ....................................... 11
Lagging ................................................... 12
Internal Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Deflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Monitoring ................................................. 12
GeoSoils, lne ..
RECOMMENDATIONS -FOUNDATIONS .................................... 12
Preliminary Foundation Design ...................................... 12
Bearing Value .............................................. 13
Lateral Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Foundation Settlement ............................................. 14
Footing Setbacks ................................................. 14
Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Very Low Expansion Potential {E.I. o to 20) ....................... 14
UTILITIES ........................................ _ ..................... 15
WALL DESIGN PARAMETERS ............................................ 15
Conventional Retaining Walls ....................................... 15
Restrained Walls ............................................ 16
Cantilevered Walls ........................................... 16
Retaining Wall Backfill and Drainage .................................. 16
Wall/Retaining Wall Footing Transitions ............................... 17
TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS .......................... 21
Slope Creep ..................................................... 21
Top of Slope Walls/Fences ......................................... 21
DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS ....................... 22
DEVELOPMENT CRITERIA ............................................... 24
Landscape Maintenance and Planting ................................ 24
Additional Site Improvements ..................... -.................. 24
Trenching ....................................................... 24
Drainage ........................................................ 25
Utility Trench Backfill .............................................. 25
SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND
TESTING ........................................................ 26
OTHER DESIGN PROFESSIONALS/CONSULTANTS .......................... 26
PLAN REVIEW ......................................................... 27
LIMITATIONS .......................................................... 27
Mr. Bernard Goldstein
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Table of Contents
Page ii
FIGURES:
Figure 1 -Site Location Map ......................................... 2
Figure 2 -California Fault Map ........................................ 5
Detail 1 -Typical Retaining Wall backfill and Drainage Detail .............. 18
Detail 2 -Retaining Wall Backfill and Subdrain detail Geotextile Drain ....... 19
Detail 3-Retaining Wall and Subdrain Detail Clean Sand Backfill ........... 20
ATTACHMENTS:
Appendix A-References ................................... Rear of Text
Appendix B -Test Pit Logs .................................. Rear of Text
Appendix C -Laboratory Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text
Appendix D -General Earthwork and Grading Guidelines ......... Rear of Text
Plate 1 -Test Pit Location Map ...................... Rear of Text in Folder
Mr. Bernard Goldstein
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Page iii
PRELIMINARY GEOTECHNICAL EVALUATION
PROPOSED OCEAN VISTA, APN 203-144-01-00, OCEAN STREET
OCEANSIDE, SAN DIEGO COUNTY, CALIFORNIA
SCOPE OF SERVICES
The scope of our services has included the following:
1. Review of the available geologic literature for the site (see Appendix A).
2. Geologic site reconnaissance, subsurface exploration, sampling and mapping.
3. Appropriate laboratory testing of representative soil samples.
4. General areal seismicity evaluation.
5. Engineering and geologic analysis of data collected.
6. Preparation of this report and accompaniments.
SITE CONDITIONS/PROPOSED DEVELOPMENT
The site consists of a rectangular, gently westward sloping property, located at the
southwest corner of the intersection of Beech Avenue and Garfield Street, in the City of
Carlsbad, California (see Figure 1, Site Location Map). The property is currently vacant.
The site is located approximately 43 to 52 feet above Mean Sea Level (MSL). Site
development is anticipated to consist of preparing the site for the construction of four
residential structures with basement/garage sub-floors and two additional stories above the
sub-floors, as well as underground utility improvements. Building loads are assumed to
be typical for this type of relatively light construction. It is anticipated that sewage disposal
will be tied into the regional municipal system. The need for import soils is unknown.
SITE EXPLORATION
Surface observations and subsurface exploration were performed on November 26, 2003,
by a representative of this office. A survey of line and grade for the subject site was not
conducted by this firm at the time of our site reconnaissance. Near surface soil conditions
were explored with five exploratory test pits excavated with a backhoe within the site to
evaluate soil and geologic conditions. The approximate location of each test pit is shown
on the Test Pit Location Map (Plate 1). Test Pit Logs are presented in Appendix B.
GeoSoils, lne ..
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CARLSBAD
Base Map: The Thomas Guide, San Diego County Street Guide and Directory, 2003 Edition,
by Thomas Bros. Maps, page 1106, 1":1/2 mile
Base Map: San Luis Rey Quadrangle, California--San Diego Co., 7 .5 Minute Series
(Topographic), 1968, by USGS, 1'':2000'
Reproduced with permission granted by Thomas Bros. Mlaps. Thia map la copyrighted by Thoma, Broa. Maps. It Is unlawful
to COPY, or reproduce all or any part thereof, wh~ther for personal use or resale, without permission. All rights reserved.
N
w.o.
4107-A-SC
SITE LO·CATl;ON MAP
Figure 1
REGIONAL GEOLOGY
The subject property is located within a prominent natural geomorphic province in
southwestern California known as the Peninsular Ranges. It is characterized by steep,
elongated mountain ranges and valleys thattrend northwesterly. The mountain ranges are
underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks,
Jurassic metavolcanic rocks, and Cretaceous plutonic rocks of the southern California
batholith.
In the San Diego County region, deposition occurred during .the Cretaceous period of the
Cenozoic era in the continental margin of a forearc basin. Sediments, derived from
Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited into the
narrow, steep, coastal plain and continental margin of the basin. These rocks have been
uplifted, eroded and deeply incised. During early Pleistocene time, a broad coastal plain
was developed from the deposition of marine terrace deposits. During mid-to late
Pleistocene time, this plain was uplifted, eroded and incised. Alluvial deposits have since
filled the lower valleys, and young marine sediments are currently being deposited/eroded
within coastal and beach areas.
SITE GEOLOGIC UNITS
The site geologic units encountered during our subsurface investigation and site
reconnaissance included topsoil/colluvium and terrace deposits. The earth materials are
generally described below from the youngest to the oldest.
Topsoil/Colluvium
Topsoil (colluvium), consisting of light brown, dry, loose silty sands, approximately 1 foot
thick, was observed mantling the site. These soils are considered potentially compressible
in their existing state and will require removal during any future grading within the site, if
settlement sensitive improvements are proposed in those areas. The earth materials can
be reused as compacted fill, provided deleterious material has been removed.
Quaternary-age Terrace Deposits
Terrace deposits were observed to underlie the site and consist generally of massive, loose
to dense with depth, silty sands. These deposits are generally red brown in color, and
moist. The upper two to three feet of these materials are generally weathered and
considered unsuitable for structural support in their present condition and should be
removed and recompacted, should settlement sensitive improvements be proposed within
their influence. These deposits were observed to be friable to a depth of approximately
8 feet. Temporary construction slopes onsite may be surficially unstable and may require
shoring. Recommendations for shoring are provided herein.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp 7\4100\4107a.pge
GeoSoils, lne.,
W.O. 4107-A-SC
December 3, 2003
Page3
FAULTING AND REGIONAL SEISMICITY
Faulting
The site is situated in a region of active as well as potentially-active faults. Our review
indicates that there are no known active faults crossing the site within the areas proposed
for development (Jennings, 1994), and the site is not within an Earthquake Fault Zone (Hart
and Bryant, 1997).
There are a number of faults in the southern California area that are considered active and
would have an effect on the site in the form of ground shaking, should they be the source
of an earthquake (Figure 2). These faults include-but are not limited to-the San Andreas
fault, the San Jacinto fault, the Elsinore fault, the Coronado Bank fault zone, and the
Newport-Inglewood -Rose Canyon fault zone. The possibility of ground acceleration or
shaking at the site may be considered as approximately similar to the southern California
region as awhole.
The following table lists the major faults and fault zones in southern California that could
have a significant effect on the site should they experience significant activity.
ABBREVIATED FAULT NAME APPROXIMATE DISTANCE MILES (KM)
Coronado Bank-Agua Blanca 19.0(30.5)
Elsinore-Temecula 26.1 (42.0)
Newport-Inglewood-Offshore 2.7 (4.3)
Rose Canyon 3.4 (5.4)
Elsinore-Julian 26.7(43.0)
Seismicity
The acceleration-attenuation relations of Sadigh, et al. (1997) Horizontal Soil, Bozorgnia,
Campbell and Niazi (1999) Horizontal-Soft Rock-Correlation and Campbell and Bozorgnia
(1997 Rev.) Horizontal-Soil have been incorporated into EQFAULT (Blake, 2000a). Forthis
study, peak horizontal ground accelerations anticipated at the site were determined based
on the random mean plus 1 -sigma attenuation curve and mean attenuation curve
developed by Joyner and Boore (1981, 1982a, 1982b, 1988, 1990), Bozorgnia, Campbell,
and Niazi (1999), and Campbell and Bozorgnia (1997). EQFAUL Tis a computer program
by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using
up to 150 digitized California faults as earthquake sources.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
W.O. 4107-A-SC
December 3, 2003
Page4
EARTHQUAKE EPICENTER MAP
Ocean Vista
1100 ~-----------------------------,
1000
900
800
700
600
500
400
300
200 LEGEND
X M =4
100
-1 00 -+--'-.......... '-'-+---'---'--'--'-+ ..................... '-+-.___._-'--'-+-'-........... _._,_,l--'-"'.___._-L+_.___,_--'--"Y-',a:;,,.u;;'---'-+-'-...,___,_--'-f.__,___,__,__'-1
-400 -300 -200 -100 0 100 200 300 400 500 600
W.O. 4107-A-SC Figure 2
GeoSoils, Inc ..
The program estimates the closest distance between each fault and a given site. If a fault
is found to be within a user-selected radius, the program estimates peak horizontal ground
acceleration that may occur at the site from an upper bound ("maximum credible")
earthquake on that fault. Site acceleration (g) is computed by one of many user-selected
acceleration-attenuation relations that are contained in EQFAULT. Based on the EQFAUL T
program, peak horizontal ground accelerations from an upper bound event at the site may
be on the order of 0.71 g to 0.85g.
Historical site seismicity was evaluated with the acceleration-attenuation relations of
Campbell and Bozorgnia (1997 Revised) Soft Rock and the computer program EQSEARCH
(Blake, 2000b). This program performs a search of the historical earthquake records for
magnitude 5.0 to 9.0 seismic events within a 100-mile radius, between the years 1800 to
2002. Based on the selected acceleration-attenuation relationship, a peak horizontal
ground acceleration is estimated, which may have effected the site during the specific event
listed. Based on the available data and the attenuation relationship used, the estimated
maximum (peak) site acceleration during the period 1800 to 2002 was 0.24g. Site specific
probability of exceeding various peak horizontal ground accelerations and a seismic
recurrence curve are also estimated/generated from the historical data. Computer printouts
of pertinent portions of the EQSEARCH program are presented in Appendix C.
A probabilistic seismic hazards analyses was performed using FRISKSP (Blake, 2000c)
which models earthquake sources as 3-D planes and evaluates the site specific
probabilities of exceedance for given peak acceleration levels or pseudo-relative velocity
levels. Based on a review of these data, and considering the relative seismic activity of the
southern California region, a peak horizontal ground acceleration of 0.40g was calculated.
This value was chosen as it corresponds to a 1 O percent probability of exceedance in
50 years (or a 475-year return period).
Seismic Shaking Parameters
Based on the site conditions, Chapter 16 of the Uniform Building Code ([UBC], International
Conference of Building Officials [ICBO], 1997}, the following seismic parameters are
provided.
Seismic zone (per Figure 16-2*)
Seismic Zone Factor (per Table 16-1*)
Soil Profile Type (per Table 16-J*)
Seismic Coefficient Ca (per Table 16-Q*)
Seismic Coefficient Cv (per Table 16-R*)
Near Source Factor Na (per Table 16-S*)
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
4
0.40
So
0.44 Na
0.64 NV
1.1
W.O. 4107-A-SC
December 3, 2003
Page6
Near Source Factor Nv (per Table 16-T*) 1.3
Seismic Source Type (per Table 16-U*) B
Distance to Seismic Source 2.7mi. (4.3 km)
Upper Bound Earthquake [Newport-Inglewood] Mw6.9
* Figure and table references from Chapter 16 of the UBC (ICBO, 1997).
Seismic Hazards
The following list includes other seismic related hazards that have been considered during
our evaluation of the site. The hazards listed are considered negligible and/or completely
mitigated as a result of site location, soil characteristics and typical site development
procedures:
• Liquefaction
• Tsunami
• Dynamic Settlement
• Surface Fault Rupture
• Ground Lurching or Shallow Ground Rupture
• Sieche
It is important to keep in perspective that in the event of a maximum probable or credible
earthquake occurring on any of the nearby major faults, strong ground shaking would occur
in the subject site's general area. Potential damage to any structure(s) would likely be
greatest from the vibrations and impelling force caused by the inertia of a structure's mass,
than from those induced by the hazards considered above. This potential would be no
greater than that for other existing structures and improvements in the immediate vicinity.
GROUNDWATER
Subsurface water was not encountered within the property during field work performed in
preparation of this report. Subsurface water is not anticipated to adversely affect site
development, provided that the recommendations contained in this report are incorporated
into final design and construction. These observations reflect site conditions at the time of
our investigation and do not preclude future changes in local groundwater conditions from
excessive irrigation, precipitation, or that were not obvious, at the time of our investigation.
Regional groundwater is estimated to be at least 40 feet in depth, below the site.
Seeps, springs, or other indications of a high groundwater level were not noted on the
subject property during the time of our field investigation. However, seepage may occur
locally (as the result of heavy precipitation or irrigation) in areas where any fill soils overlie
terrace deposits. Such conditions may occur during grading or after the site is developed.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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W.O. 4107-A-SC
December 3, 2003
Page?
LABORATORY TESTING
General
Laboratory tests were performed on representative samples of the onsite earth materials
in order to evaluate their physical characteristics. The test procedures used and results
obtained are presented below.
Classification
Soils were classified visually according to the Unified Soils Classification System (USCS).
The soil classifications are shown on the Test Pit Logs in Appendix B.
Moisture-Density Relations
The field moisture contents and dry unit weights was determined for a selected undisturbed
sample in the laboratory. The dry unit weight was determined in pounds per cubic
foot (pcf), and the field moisture content was determined as a percentage of the dry weight.
The results of these tests are shown on the Test Pit Logs in Appendix B.
Laboratory Standard
The maximum dry density and optimum moisture content was determined for the major soil
type encountered in the borings. The laboratory standard used was ASTM D-1557. The
moisture-density relationship obtained for this soil is shown below:
MAXIMUM DRY OPTIMUM
SOIL TYPE TEST PIT AND DENSITY MOISTURE
DEPTH (FT.) (PCF) CONTENT(%)
SIL TY SAND, Red Brown TP-1 @3 128.5 9.5
Expansion Potential
Expansion testing was performed on representative samples of site soil in accordance with
UBC Standard 18-2. The results of expansion testing are presented in the following table.
I LOCATION
I
TP-1 @ 3'
TP-2@5'
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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I EXPANSION INDEX
I
1
1
I EXPANSION POTENTIAL
I
Very Low
Very Low
I
I
W.O. 4107-A-SC
December 3, 2003
Page 8
Direct Shear Test
Shear testing was performed on a representative, undisturbed sample of site soil in general
accordance with ASTM test method D-3080 in a Direct Shear Machine of the strain control
type. The shear test result is as follows:
PRIMARY RESIDUAL
SAMPLE
LOCATION COHESION FRICTION ANGLE-COHESION FRICTION ANGLE
(PSF) (DEGREES) (PSF) (DEGREES)
I TP-1@ 3' I 113 I 38 I 113 I 31 I
Corrosion/Sulfate Testing
Laboratory test results for soluble sulfates, pH, and corrosion to metals have not been
received as of the date of this report. Testing will be presented as an addendum upon
receipt of the results. Additional testing of site materials is recommended when proposed
grading is complete to verify the findings.
CONCLUSIONS
Based upon our site reconnaissance, subsurface exploration, and laboratory test results,
it is our opinion that the subject site appears suitable for the proposed residential
development. The following recommendations should be incorporated into the construction
details.
EARTHWORK CONSTRUCTION RECOMMENDATIONS
General
All grading should conform to the guidelines presented in Appendix Chapter A33 of the
UBC, the requirements of the City, and the Grading Guidelines presented in Appendix D,
except where specifically superseded in the text of this report. Prior to grading, a GSI
representative should be present at the preconstruction meeting to provide additional
grading guidelines, if needed, and review the earthwork schedule.
During earthwork construction all site preparation and the general grading procedures of
the contractor should be observed and the fill selectively tested by a representative(s) of
GSI. If unusual or unexpected conditions are exposed in the field, they should be reviewed
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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December 3, 2003
Page9
by this office and if warranted, modified and/or additional recommendations will be offered.
All applicable requirements of local and national construction and general industry safety
orders, the Occupational Safety and Health Act, and the Construction Safety Act should be
met.
Site Preparation
Debris, vegetation, existing structures, and other deleterious material should be removed
from the building area prior to the start of construction. Sloping areas to receive fill should
be properly benched in accordance with current industry standards of practice and
guidelines specified in the Uniform Building Code.
Removals (Unsuitable Surficial Materials)
Due to the relatively loose condition of topsoil and weathered terrace deposits, these
materials should be removed and recompacted in areas proposed for settlement sensitive
structures or areas to receive compacted fill. At this time, removal depths on the order of
3 to 4 feet (including topsoil and weathered terrace deposits) below existing grade should
be anticipated throughout a majority of the site; however, locally deeper removals cannot
be precluded. Removals should be completed below a 1: 1 projection down and away from
the edge of any settlement sensitive structure and/or limit of proposed fill. Once removals
are completed, the exposed bottom should be reprocessed and compacted to 90 percent
relative compaction.
Fill Placement
Subsequent to ground preparation, onsite soils may be placed in thin (±6-inch) lifts,
cleaned of vegetation and debris, brought to a least optimum moisture content, and
compacted to achieve a minimum relative compaction of 90 percent. If soil importation is
planned, a sample of the soil import should be evaluated by this office prior to importing,
in order to assure compatibility with the onsite site soils and the recommendations
presented in this report. Import soils for a fill cap should be low expansive (expansion
index [E.I.] less than 50). The use of subdrains at the bottom of the fill cap may be
necessary, and subsequently recommended based on compatibility with onsite soils and
proximity and/or suitability of an outlet.
Transitions/Overexcavation
Cut portions of cut/fill transition pads should be overexcavated a minimum 3 feet below pad
grade. Areas with planned fills less than 3 feet should be over excavated in order to provide
to minimum fill thickness. Where the ratio of maximum to minimum fill thickness below a
given structure exceeds 3:1, overexcavation should be completed to reduce this ratio
to 3: 1 , or less.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
W.O. 4107-A-SC
December 3, 2003
Page 10
Temporary Construction Slopes
Proposed site development consists of excavation for garage/basement sub-floors.
Temporary cuts for wall construction should be constructed at a gradient of 1: 1 or flatter for
slopes exposing terrace deposit materials to a maximum height of 15 feet, per CAL-OSHA
for Type B soils. Construction materials and/or stockpiled soil should not be stored within
5 feet of the top of any temporary slope. Temporary/permanent provisions should be made
to direct any potential runoff away from the top of temporary slopes. Shoring will likely be
required, due to the friable conditions of the terrace deposits to a depth of approximately
8 feet.
Shoring
General
Should insufficient space for constructing portions of the proposed residence be
encountered, shoring may be required. Shoring should consist of cantilever steel soldier
beams placed at a maximum of 6-foot on centers, with a minimum embedment below the
bottom of the cut, equivalent to half the height of the cut. The ultimate embedment depth
should be provided by the project structural engineer and/or shoring designer, based on
the geotechnical parameters provided herein. Wood lagging should be installed as the cut
progresses to its ultimate configuration.
Lateral Pressures
For design on cantilevered shoring, a triangular distribution of lateral earth pressure may
be used. It may be assumed that the retained soils with a level surface behind the shoring
will exert a lateral pressure equal to that developed by a fluid with a density of 40 pcf.
Retained soils with a 2:1 back slope ratio will exert a lateral pressure equal to a fluid with
a density of 60 pcf.
If street traffic is located within 10 feet of shorings, the upper 1 O feet of shoring adjacent to
the traffic should be designed to resist a uniform lateral pressure of 100 pounds per square
foot (psf), which is a result of an assumed 300 psf surcharge behind the shoring due to
normal street traffic.
Design of Soldier Piles
For the design of soldier piles spaced at least two diameters on centers, the allowable
lateral bearing value (passive value) of the soils below the level of excavation may be
assumed to be 500 psf per depth, up to a maximum of 5,000 psf. To develop the full lateral
value, provisions should be taken to assure firm contact between the soldier piles and the
undisturbed soils.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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December 3, 2003
Page 11
The soldier piles below the excavated levels may be used to resist downward loads, if any.
The downward frictional resistance between the soldier piles and the soils below the
excavated level may be taken as equal to 300 psf.
Lagging
Continuous wood lagging will be required between the soldier piles. The soldier piles
should be designed for the full anticipated lateral pressure. However, the pressure on the
lagging will be less due to arching in the soils. We recommend that the lagging be
designed for the recommended earth pressure, but limited to a maximum value of 500 psf.
Internal Bracing
Rakers may be required to internally brace the soldier piles. The raker bracing could be
supported laterally by temporary concrete footings (deadmen) or bythe permanent interior
footings. For design of temporary footings, or deadmen, poured with the bearing surface
normal to rakers inclined at 45 degrees, a bearing value of 2,500 psf may be used, provided
the shallowest point of the footing is at least 1 foot below the lowest adjacent grade.
Deflection
It is difficult to accurately predict the amount of deflection of a shored profile. It should be
realized, however, that some deflection will occur. We anticipate that this deflection would
be on the order of 0.5 inch at the top of the planned 10-to 12-foot shoring. If greater
deflection occurs during construction, additional bracing may be necessary to minimize
deflection. If desired to reduce the deflection of the shoring, a greater active pressure
leading to a more stiffer section could be used.
Monitoring
Some means of monitoring the performance of the shoring system is recommended. The
monitoring should consist of periodic surveying of the lateral and vertical locations of the
tops of all the soldier piles and the lateral movement along the entire lengths of selected
soldier piles. We suggest that photographs of the adjacent improvements be made prior
to excavation.
RECOMMENDATIONS -FOUNDATIONS
Preliminary Foundation Design
In the event that the information concerning the proposed development plans are not
correct or any changes in the design, location, or loading conditions of the proposed
structures are made, the conclusions and recommendations contained in this report are for
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Ocean Vista, Carlsbad
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Page 12
the subject site only and shall not be considered valid unless the changes are reviewed
and conclusions of this report are modified or approved in writing by this office.
The information and recommendations presented in this section are considered minimums
and are not meant to supersede design(s) by the project structural engineer or civil
engineer specializing in structural design. Upon request, GSI could provide additional
consultation regarding soil parameters, as related to foundation design. They are
considered preliminary recommendations for proposed construction, in consideration ofour
field investigation, and laboratory testing and engineering analysis.
Our review, field work, and recent and previous laboratory testing indicates that onsite soils
have a very low expansion potential range (E.1. Oto 20). Preliminary recommendations for
foundation design and construction are presented below. Final foundation
recommendations should be provided at the conclusion of grading based on laboratory
testing of fill materials exposed at finish grade.
Bearing Value
1. The foundation systems should be designed and constructed in accordance with
guidelines presented in the latest edition of the UBC.
2. An allowable bearing value of 2,000 psf may be used for design of continuous
footings 12 inches wide and 12 inches deep and for design of isolated pad footings
24 inches square and 18 inches deep founded entirely into compacted fill or
competent formational material and connected by grade beam or tie beam in at
least one direction. This value may be increased by 20 percent for each additional
12 inches in depth to a maximum value of 3,000 psf. The above values may be
increased by one-third when considering short duration seismic or wind loads. No
increase in bearing for footing width is recommended.
Lateral Pressure
1. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a
concrete to soil contact when multiplied by the dead load.
2. Passive earth pressure may be computed as an equivalent fluid having a density of
250 pcf with a maximum earth pressure of 2,500 psf.
3. When combining passive pressure and frictional resistance, the passive pressure
_ component should be reduced by one-third.
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Ocean Vista, Carlsbad
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December 3, 2003
Page 13
Foundation Settlement
Foundations systems should be designed to accommodate a worst case differential
settlement of 1 inch in a 40-foot span.
Footing Setbacks
All footings should maintain a minimum ?-foot horizontal setback from the base of the
footing to any descending slope. This distance is measured from the footing face at the
bearing elevation. Footings should maintain a minimum horizontal setback of H/3
(H =slope height) from the base of the footing to the descending slope face and no less than
7 feet nor need to be greater than 40 feet. Footings adjacent to unlined drainage swales
should be deepened to a minimum of 6 inches below the invert of the adjacent unlined
swale. Footings for structures adjacent to retaining walls should be deepened so as to
extend below a 1: 1 projection from the heel of the wall. Alternatively, walls may be
designed to accommodate structural loads from buildings or appurtenances as described
in the retaining wall section of this report.
Construction
The following foundation construction recommendations are presented as a minimum
criteria from a soils engineering standpoint. The onsite soils expansion potentials are
generally very low (E.I. Oto 20). Recommendations for very low expansive soil conditions
are presented herein.
Recommendations by the project's design-structural engineer or architect, which may
exceed the soils engineer's recommendations, should take precedence over the following
minimum requirements. Final foundation design will be provided based on the expansion
potential of the near surface soils encountered during grading.
Very Low Expansion Potential (E.I. O to 20)
1. Exterior and interior footings should be founded at a minimum depth of 12 inches for
one-story floor loads, 18 inches for two-story floor loads, and 24 inches for three
story floor loads, below the lowest adjacent ground surface. Isolated column and
panel pads or wall footings should be founded at a minimum depth of 18 inches,
excluding the landscape zone (top 6 inches). All footings should be reinforced with
two No. 4 reinforcing bars, one placed nearthetop and one placed nearthe bottom
of the footing. Footing widths should be as indicated in the UBC (ICBO, 1997).
2. A grade beam, reinforced as above, and at least 12 inches wide should be provided
across large (e.g., doorways) entrances. The base of the grade beam should be at
the same elevation as the bottom of adjoining footings. Isolated, exterior square
footings should be tied within the main foundation in at least one direction with a
grade beam.
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Ocean Vista, Carlsbad
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Page 14
3. Residential concrete slabs, where moisture condensation is undesirable, should be
underlain with a vapor barrier consisting of a minimum of 1 o mil polyvinyl chloride
or equivalent membrane with all laps sealed. This membrane should be covered
above and below with a minimum of 2 inches of sand (total of 4 inches) to aid in
uniform curing of the concrete and to protect the membrane from puncture.
4. Residential concrete slabs should be a minimum of 4 inches thick, and should be
reinforced with No. 3 reinforcing bar at 18 inches on center in both directions. All
slab reinforcement should be supported to ensure placement near the vertical
midpoint of the concrete. 11Hooking11 of reinforcement is not considered an
acceptable method of positioning the reinforcement.
5. Residential garage slabs should be a minimum of 5 inches thick and should be
reinforced as above and poured separately from the structural footings and
quartered with expansion joints or saw cuts. A positive separation from the footings
should be maintained with expansion joinf material to permit relative movement.
6. Presaturation is not required for these soil conditions. The moisture content of the
subgrade soils should be equal to or greater than optimum moisture content in the
slab areas prior to the placement to visqueen.
UTILITIES
Utilities should be enclosed within a closed utilidor (vault) or designed with flexible
connections to accommodate differential settlement and expansive soil conditions. Due
to the potential for differential settlement, air conditioning (A/C) units should be supported
by slabs that are incorporated into the building foundation or constructed on a rigid slab with
flexible couplings for plumbing and electrical lines. A/C waste waterlines should be
drained to a suitable outlet.
WALL DESIGN PARAMETERS
Conventional Retaining Walls
The design parameters provided below assume that either non expansive soils (Class 2
permeable filter material or Class 3 aggregate base) or native materials (up to and
including medium expansion poteritial) are used to backfill any retaining walls. The type
of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown
on the plans. Building walls, below grade, should be water-proofed or damp-proofed,
depending on the degree of moisture protection desired. The foundation system for the
proposed retaining walls should be designed in accordance with the recommendations
presented in this and preceding sections of this report, as appropriate. Footings should be
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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December 3, 2003
Page 15
embedded a minimum of 18 inches below adjacent grade (excluding landscape layer,
6 inches) and should be 24 inches in width. There should be no increase in bearing for
footing width. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can
be provided upon request, and would be based on site specific conditions.
Restrained Walls
Any retaining walls that will be restrained prior to placing and compacting backfill material
or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid
pressure (EFP) of 65 pounds per cubic foot (pcf), plus any applicable surcharge loading.
For areas of male or re-entrant corners, the restrained wall design should extend a
minimum distance of twice the height of the wall (2H) laterally from the corner.
Cantilevered Walls
The recommendations presented below are for cantilevered retaining walls up to 1 O feet
high. Design parameters for walls less than 3 feet in height may be superseded by City
and/or County standard design. 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 due to traffic,
structures, seismic events or adverse geologic conditions. When wall configurations are
finalized, the appropriate loading conditions for superimposed loads can be provided upon
request.
SURFACE SLOPE OF EQUIVALENT EQUIVALENT
RETAINED MATERIAL FLUID WEIGHT P.C.F. FLUID WEIGHT P.C.F.
HORIZONTAL TO VERTICAL (SELECT BACKFILL) (NATIVE BACKFILL)
Level* 35 45
2 to 1 50 60
* Level backfill behind a retaining wall is defined as compacted earth materials,
properly drained, without a slope for a distance of 2H behind the wall, where His the
height of the wall.
Retaining Wall Backfill and Drainage
Positive drainage must be provided behind all retaining walls in the form of gravel wrapped
in geofabric and outlets. A backdrain system is considered necessary for retaining walls
that are 2 feet or greater in height. Details 1, 2, and 3, present the back drainage options
discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS
pipe encased in either Class 2 permeable filter material or ½-inch to ¾-inch gravel wrapped
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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December 3, 2003
Page 16
in approved filter fabric (Mirafi 140 or equivalent). For low expansive backfill, the filter
material should extend a minimum of 1 horizontal foot behind the base of the walls and
upward at least 1 foot. For native backfill that has up to medium expansion potential,
continuous Class 2 permeable drain materials should be used behind the wall. This
material should be continuous (i.e., full height) behind the wall, and it should be constructed
in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage
Detail). For limited access and confined areas, (panel) drainage behind the wall may be
constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail
Geotextile Drain). Materials with an expansion index (E.1.) potential of greater than
90 should not be used as backfill for retaining walls. For more onerous expansive
situations, backfill and drainage behind the retaining • wall should conform with
Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill).
Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than
± 100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes
in walls higher than 2 feet should not be considered. The surface of the backfill should be
sealed by pavement or the top 18 inches compacted with native soil (E.I. <90). Proper
surface drainage should also be provided. For additional mitigation, consideration should
be given to applying a water-proof membrane to the back of all retaining structures. The
use of a waterstop should be considered for all concrete and masonry joints.
Wall/Retaining Wall Footing Transitions
Site walls are anticipated to be founded on footings designed in accordance with the
recommendations in this report. Should wall footings transition from cut to fill, the civil
designer may specify either:
a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a
distance of 2H, from the point of transition.
b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints
or crack control joints) such that a angular distortion of 1 /360 for a distance of 2H on
either side of the transition may be accommodated. Expansion joints should be
sealed with a flexible, non-shrink grout.
c) Embed the footings entirely into native formational material (i.e., deepened footings).
If transitions from cut to fill transect the wall footing alignment at an angle of less than
45 degrees (plan view), then the designer should follow recommendation "a" (above) and
until such transition is between 45 and 90 degrees to the wall alignment.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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December 3, 2003
Page 17
Provide surf a.ce clra.ina.ge
±12'
(D Va. ter proofing
MeMbra.ne (optiona.l)
® Veephole
Finished surfa.ce
DETAIL
N . T . S .
Na. tive Ba.ckf ill
Slope or Level
Na. tlve Ba.ckfill
@ Filter fa.bric
G)Plpe
(D VATER PROOFING MEMBRANE (optlona.l)1
Liquid boot or o.pproved equivo.lent.
@ ROCK1
3/4 to 1-1/2' (Inches) rock.
@ FILTER F ABRIC1
Mira.fl 140N or o.pprovecl equlva.lent plo.ce fa.bric flo.p behind core.
G) PIPE1
4' (Inches) di a.Meter perforo. ted PVC, schedule 40 or o.pproveol
o.l terno. tlve with MlnlMUM of 1% gro.dient to proper outlet point,
@ \/EEPHDLE1
MlnlMUM 2" (Inches) dla.Meter plo.cecl a.t 20' (feet) on centers
a.long the wo.ll, o.ncl 3' (Inches) o.loove finished surf o.ce.
E
.· .
:,· .
'i(i.:.
TYPICAL RETAINING WALL BACKFILL
AND DRAINAGE DETAIL
DETAIL 1
Geotechnical •Geologic• Environmental
DETAIL
N , T . S
Provide surf o.ce dra.lno.ge Na. tive Bo.ckfill
or Level
(D \Jo. ter proofing
MeMbro.ne (optiot;o.D)
@ \Jeephole
Finished surfa.ce
No. tive Bo.ckf ill
@Dre.in
@Filter
fa.bric
G)Pipe
(D \J ATER PROOFING MEMBRANE (optlonal)1
Liquid boot or approved equlva.lent,
@ DRAIN1
Mlro.olro.ln 6000 or J-olro.ln 200 or equiva.lent for
non-wo. terproof eel wo.lls,
Miro.clro.ln 6200 or J-olro.ln 200 or equlva.lent for
wa. ter proofeol wo.lls.
@ FILTER F ABRIC1
Miro. fl 140N or o.pprovecl equlvo.lent pla.ce f o.brlc fla.p behind core,
@ PIPE1
4• (Inches) olla.Meter perforo.tecl PVC. schedule -40 or approved
a.lterno. tlve with MlnlMUM of 11/. gra.ollent to proper outlet point,
@ \./EEPH □LE1
MlnlMuM 21 (Inches) clla.Meter plo.cecl o.t 20' (feet) on centers
a.long the wo.ll, a.nol 3• (Inches) a.bove flnlshecl surf o.cie.
RETAINING WALL BACKFILL AND
SUBDRAIN DETAIL •
GEOTEXTILE DRAIN
DETAIL 2
Geotechnical •Geologic• Environmental
DETAIL
N , T . S
No. tlve Bo.ck fill
Provide surfo.ce dro.ino.ge 2 Slope o~evel
H
±12'
(§) 'w'eephole
Finished surfo.ce
.. @Filter·
· fa.bric
4 Rock
-Heel width
(D 'w' ATER PROOFING MEMBRANE (optlono.D1
Llqulol boot or npproved equlvo.lent.
@ CLEAN SAND BACKFILL1
Must ho. ve so.no! equlvnlent vo.lue of 30 or greo. ter J
ca.n be olenslfleol by wa. ter Jetting,
@ FILTER F ABRIC1
Miro.fl 140N or o.pproveol equlvo.lent,
@ RDCK1
1 cubic foot per llneo.r feet of pipe of 3/4 to 1-1/2' (Inches) rock
@ PIPE,
4' (Inches) di a.Meter perf ora. tecl PVC, schedule 40 or a.pprovecl
a.l terno. tlve with MlnlMUM of 11/. gra.ollent to proper outlet point,
@ \JEEPH□LE•
Mini MUM 2• Cinches) dla.Meter pla.ced o. t 20' (feet) on centers
a.long the wall, o.nol 3' (Inches) a.bove finished surf o.ce,
i;:
n.,,.-,,,., .••
:!:·<•.·.· .. ~:· -·:. \~. '
RETAINING WALL AND SUBDRAIN DETAIL
CLEAN SAND BACKFILL
DETAIL 3
Geotechnical • Geologic• Environmental
TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS
Slope Creep
Some soils at the site may be expansive and therefore, may become desiccated when
allowed to dry. Such soils are susceptible to surficial slope creep, especially with seasonal
changes in moisture content. Typically in southern California, during the hot and dry
summer period, these soils become desiccated and shrink, thereby developing surface
cracks. The extent and depth of these shrinkage cracks depend on many factors such as
the nature and expansivity of the soils, temperature and humidity, and extraction of
moisture from surface soils by plants and roots. When seasonal rains occur, water
percolates into the cracks and fissures, causing slope surfaces to expand, with a
corresponding loss in soil density and shear strength near the slope surface. With the
passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials
experience a very slow, but progressive, outward and downward movement, known as
slope creep. For slope heights greater than 1 o feet, this creep related soil movement will
typically impact all rear yard flatwork and other secondary improvements that are located
within about 15 feet from the top of slopes, such as swimming pools, concrete flatwork, etc.,
and in particular top of slope fences/walls. This influence is normally in the form of
detrimental settlement, and tilting of the proposed improvements. The dessication/swelling
and creep discussed above continues over the life of the improvements, and generally
becomes progressively worse. Accordingly, the developer should provide this information
to any homeowners and homeowners association.
Top of Slope Walls/Fences
Due to the potential for slope creep for slopes higher than about 1 O feet, some settlement
and tilting of the walls/fence with the corresponding distresses, should be expected. To
mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be
constructed on a combination of grade beam and caisson foundations. The grade beam
should be at a minimum of 12 inches by 12 inches in cross section, supported by drilled
caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on
center, and with a minimum embedment length of 7 feet below the bottom of the grade
beam. The strength of the concrete and grout should be evaluated by the structural
engineer of record. The proper ASTM tests for the concrete and mortar should be provided
along with the slump quantities. The concrete used should be appropriate to mitigate
sulfate corrosion, as warranted. The design of the grade beam and caissons should be in
accordance with the recommendations of the project structural engineer, and include the
utilization of the following geotechnical parameters:
Creep Zone:
Creep load:
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
5-footvertical zone below the slope face and projected upward
parallel to the slope face.
The creep load projected on the area of the grade beam should
be taken as an equivalent fluid approach, having a density of
W.O. 4107-A-SC
December 3, 2003
Page 21
Point of Fixity:
Passive Resistance:
Allowable Axial Capacity:
Shaft capacity :
Tip capacity:
60 pcf. For the caisson, it should be taken as a uniform
900 pounds per linear foot of caisson's depth, located above
the creep zone.
Located a distance of 1.5 times the caisson's diameter, below
the creep zone.
Passive earth pressure of 300 psf per foot of depth per foot of
caisson diameter, to a maximum value of 4,500 psf may be
used to determine caisson depth and spacing, provided that
they meet or exceed the minimum requirements stated above.
To determine the total lateral resistance, the contribution of the
creep prone zone above the point of fixity, to passive
resistance, should be disregarded.
350 psf applied below the point of fixity over the surface area
of the shaft.
4,500 psf.
DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS
Some of the soil materials onsite may be expansive. The effects of expansive soils are
cumulative, and typically occur over the lifetime of any improvements. On relatively level
areas, when the soils are allowed to dry, the dessication and swelling process tends to
cause heaving and distress to flatwork and other improvements. The resulting potential for
distress to improvements may be reduced, but not totally eliminated. To that end, it is
recommended that the developer should notify any homeowners or homeowners
association of this long-term potential for distress .. To reduce the likelihood of distress, the
following recommendations are presented for all exterior flatwork on expansive soils:
1. The subgrade area for concrete slabs should be compacted to achieve a minimum
90 percent relative compaction, and then be presoaked to 2 to 3 percentage points
above (or 125 percent of) the soils' optimum moisture content, to a depth of
18 inches below subgrade elevation. The moisture content of the subgrade should
be verified within 72 hours prior to pouring concrete.
2. Concrete slabs should be cast over a relatively non-yielding surface, consisting of
a4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and
level prior to pouring concrete. The layer should wet-down completely prior to
pouring concrete, to minimize loss of concrete moisture to the surrounding earth
materials.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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Page 22
3. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and
approaches should additionally have a thickened edge (12 inches) adjacent to all
landscape areas, to help impede infiltration of landscape water under the slab.
4. The use of transverse and longitudinal control joints are recommended to help
control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate
such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile
strength of the slab; and, b) provide an adequate amount of control and/or
expansion joints to accommodate anticipated concrete shrinkage and expansion.
In order to reduce the potential for unsightly cracks, slabs should be reinforced at
mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each
direction. The exterior slabs should be scored or saw cut,½ to 3/a inches deep, often
enough so that no section is greater than 1 o feet by 1 O feet. For sidewalks or narrow
slabs, control joints should be provided at intervals of every 6 feet. The slabs should
be separated from the foundations and sidewalks with expansion jointfiller material.
5. No traffic should be allowed upon the newly poured concrete slabs until they have
been properly cured to within 75 percent of design strength. Concrete compression
strength should be a minimum of 2,500 psi.
6. Driveways, sidewalks, and patio slabs adjacent to the house should be separated
from the house with thick expansion joint filler material. In areas directly adjacent
to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be
additionally sealed with flexible mastic.
7. Planters and walls should not be tied to the house.
8. Overhang structures should be supported on the slabs, or structurally designed with
continuous footings tied in at least two directions.
9. Any masonry landscape walls that are to be constructed throughout the property
should be grouted and articulated in segments no more than 20 feet long. These
segments should be keyed or doweled together.
10. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible
connections to accommodate differential settlement and expansive soil conditions.
11 . Positive site drainage should be maintained at all times. Finish grade on the lots
should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It
should be kept in mind that drainage reversals could occur, including
post-construction settlement, if relatively flat yard drainage gradients are not
periodically maintained by the homeowner or homeowners association.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
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December 3, 2003
Page 23
12. Air conditioning (NC) units should be supported by slabs that are incorporated into
the building foundation or constructed on a rigid slab with flexible couplings for
plumbing and electrical lines. NC waste water lines should be drained to a suitable
non-erosive outlet.
13. Shrinkage cracks could become excessive if proper finishing and curing practices
are not followed. Finishing and curing practices should be performed per the
Portland Cement Association Guidelines. Mix design should incorporate rate of
curing for climate and time of year, sulfate content of soils, corrosion potential of
soils, and fertilizers used on site.
DEVELOPMENT CRITERIA
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. Overwatering should be avoided.
Graded slopes constructed within and utilizing onsite materials would be erosive. Eroded
debris may be minimized and surficial slope stability enhanced by establishing and
maintaining a suitable vegetation cover soon after construction. Plants selected for
landscaping should be light weight, deep rooted types which r,equire little water and are
capable of surviving the prevailing climate. Compaction to the face offill slopes would tend
to minimize short term erosion until vegetation is established. In order to minimize erosion
on a slope face, an erosion control fabric (i.e., jute matting) should be considered.
From a geotechnical standpoint leaching is not recommended for establishing landscaping.
If the surface soils area processed for the purpose of adding amendments they should be
recompacted to 90 percent relative compaction.
Additional Site Improvements
Recommendations for additional grading, exterior concrete flatwork design and
construction, including driveways, can be provided upon request. If in the future, any
additional improvements are planned for the site, recommendations concerning the
geological or geotechnical aspects of design and construction of said improvements could
be provided upon request.
Trenching
All footing trench excavations for structures and walls should be observed and approved
by a representative of this office prior to placing reinforcement. Footing trench spoil and any
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
GeoSoH.s, lne ..
W.O. 4107-A-SC
December 3, 2003
Page 24
excess soils generated from utility trench excavations should be compacted to a minimum
relative compaction of 90 percent if not removed from the site. All excavations should be
observed by one of our representatives and conform to CAL-OSHA and local safety codes.
GSI does not consult in the area of safety engineers.
In addition, the potential for encountering hard spots during footing and utility trench
excavations should be anticipated. If these concretions are encountered within the
proposed footing trench, they should be removed, which could produce larger excavated
areas within the footing or utility trenches.
Drainage
Positive site drainage should be maintained at all times. Drainage should not flow
uncontrolled down any descending slope. Water should be directed away from foundations
and not allowed to pond and/or seep into the ground. Pad drainage should be directed
toward the street or other approved area. Roof gutters and down spouts should be
considered to control roof drainage. Down spouts should outlet a minimum of 5 feet from
the proposed structure or into a subsurface drainage system. We would recommend that
any proposed open bottom planters adjacent to proposed structures be eliminated for a
minimum distance of 1 O feet. As an alternative, closed bottom type planters could be
utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage
away from structures or any exterior concrete flatwork.
Utility Trench Backfill
1. All utility trench backfill in structural areas, slopes, and beneath hardscape features
should be brought to near optimum moisture content and then compacted to obtain
a minimum relative compaction of 90 percent of the laboratory standard.
Flooding/jetting is not recommended for the site soil materials. As an alternative,
imported sandy material with an S.E. of 30 or greater, may be flooded/jetted in
shallow (± 12 inches or less) under-slab interior trenches, only.
2. Sand backfill, unless trench excavation material, should not be allowed in exterior
trenches adjacent to and within an area extending below a 1: 1 plane projected from
the outside bottom edge of the footing.
3. All trench excavations should minimally conform to CAL-OSHA and local safety
codes.
4. Soils generated from utility trench excavations to be used onsite should be
compacted to 90 percent minimum relative compaction. This material must not alter
positive drainage p~tterns that direct drainage away from the structural area and
towards the street.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
W.O. 4107-A-SC
December 3, 2003
Page 25
SUMMARY OF RECOMMENDATIONS REGARDING
GEOTl:CHNICAL OBSERVATION AND TESTING
We recommend that observation and/or testing be performed by GSI at each of the
following construction stages:
• During grading/recertification.
• After excavation of building footings, retaining wall footings, and free standing walls
footings, prior to the placement of reinforcing steel or concrete.
• Prior to pouring any slabs orflatwork,after presoaking/presaturation of building pads
and other flatwork subgrade, before the placement of concrete, reinforcing steel,
capillary break (i.e .. , sand, pea-gravel, etc.), or vapor barriers (i.e., visqueen, etc.).
• During retaining wall subdrain installation, prior to backfill placement.
• During placement of backfill for area drain, interior plumbing, utility line trenches,
and retaining wall backfill.
• During slope construction/repair.
• When any unusual soil conditions are encountered during any construction
operations, subsequent to the issuance of this report.
• When any developer or homeowner improvements, such as flatwork, spas, pools,
walls, etc., are constructed.
• A report of geote!chnical observation· and testing should be provided at the
conclusion of each of the above stages, in order to provide concise and clear
documentation of site work, and/or to comply with code requirements.
OTHER DESIGN PROFESSIONALS/CONSULTANTS
The design civil engineer, structural engineer, post-tension designer, architect, landscape
architect, wall designer, etc., should review the recommendations provided herein,
incorporate those recommendations into all their respective plans, and by explicit
reference, make this report part of their project plans.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
GeoSoils, lne ..
W.O. 4107-A-SC
December 3, 2003
Page 26
PLAN REVIEW
Final site development and foundation plans should be submitted to this office for review
and comment, as the plans become available, for the purpose of minimizing any
misunderstandings between the plans and recommendations presented herein. In
addition, foundation excavations and any additional earthwork construction performed on
the site should be observed and tested by this office. If conditions are found to differ
substantially from those stated, appropriate recommendations would be offered at that time.
LIMITATIONS
The materials encountered on the project site and utilized in our laboratory study are
believed representative of the area; however, soil and bedrock materials vary in character
between excavations and natural outcrops or conditions exposed during mass grading. site
conditions may vary due to seasonal changes or other factors. GSI assumes no
responsibility or liability for work, testing or recommendations performed or provided by
others. The scope of work was performed within the limits of a budget. Inasmuch as our
study is based upon the site materials observed, selective laboratory testing and
engineering analysis, the conclusion and recommendations are professional opinions.
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.
Mr. Bernard Goldstein
Ocean Vista, Carlsbad
File:e:wp7\4100\4107a.pge
W.O. 4107-A-SC
December 3, 2003
Page 27
APPENDIX A
REFERENCES
APPENDIX A
REFERENCES
Blake, T.F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal
acceleration from 3-D fault sources; Windows 95/98 version.
__ , 2000b, EQSEARCH, A computer program for the estimation of peak horizontal
acceleration from California historical earthquake catalogs; Updated to June, 2003,
Windows 95/98 version.
__ , 2000c, FRISKSP, A computer program for the probabilistic estimation of peak
acceleration and uniform hazard spectra using 3-D faults as earthquake sources;
Windows 95/98 version.
Campbell, K.W. and Bozorgnia, Y., 1994, Near-source attenuation of peak horizontal
acceleration from worldwide accelrograms recorded from 1957 to 1993;
Proceedings, Fifth U.S. National Conference on Earthquake Engineering, volume 111,
Earthquake Engineering Research Institute, pp 292-293.
International Conference of building officials, 1997, Uniform building code: Whittier,
California, vol. 1, 2, and 3.
Jennings, C.W., 1994, Fault activity map of California and adjacent areas: California
Division of Mines and Geology, map sheet no. 6, scale 1 :750,000.
Joyner, W.B., and Boore, D.M., 1982, Estimation of response-spectral values as functions
of magnitude, distance and site conditions, in ,eds., Johnson, J.A., Campbell, K.W.,
and Blake, T.F., AEG Short Course, Seismic Hazard Analysis, dated June 18, 1994.
Kennedy, M.P. and Tan S.S., 1996, Geologic maps of the northwest part of San Diego
County, California, Division of Mines and Geology, plate 1, scale 1 :24,000.
Petersen, Mark D., Bryant, W.A., and Cramer, C.H., 1996, Interim table offault parameters
used by the California Division of Mines and Geology to compile the probabilistic
seismic hazard maps of California.
Sadigh, K., Egan, J., and Youngs, R., 1987, Predictive ground motion equations reported
in Joyner, W.B., and Boore, D.M., 1988, 11Measurement, Characterization, and
Prediction of Strong Ground Motion," in Earthquake Engineering and Soil Dynamics
11, Recent Advances in Ground Motion Evaluation, Von Thun, J.L., ed.: American
Society of Civil Engineers Geotechnical Special Publication No. 20, pp; 43-102.
Sowers and Sowers, 1970, Unified soil classification system (After U. S. Waterways
Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York.
APPENDIX B
TEST PIT LOGS
TEST SAMPLE
PIT NO. DEPTH GROUP DEPTH
(ft.) SYMBOL (ft.)
TP-1 0-1 SM
1-10 SM Bulk and
Ring@3
TP-2 0-1 SM
1-5 SM Bulk@5
W.O. 4107-A-SC
Goldstein/Ocean Vista
November 26, 2003
LOG OF EXPLORATORY TEST PITS
FIELD DRY
MOISTURE DENSITY DESCRIPTION
(%) (pcf)
TOPSOIL: SIL TY SAND, light brown, dry, very loose;
cohesionless, very fine grained.
5.3 113.5 TERRACE DEPOSITS: SIL TY SAND, red brown, very
moist, loose to medium dense; @ 8' becomes very
dense and less friable.
Total Depth = 1 0'
No Groundwater Encountered
Backfilled 11-26-2003
TOPSOIL: SIL TY SAND, light brown, dry, very loose.
TERRACE DEPOSITS: SILTY SAND, red brown, very
moist, loose to medium dense (denser w/depth).
Total Depth = 5'
No Groundwater Encountered
Backfilled 11-26-2003
PLATE 8-1
TEST SAMPLE
PITNO. DEPTH GROUP DEPTH
(ft.) SYMBOL (ft.)
TP-3 0-1 SM
1-5 SM
TP-4 0-1 SM
1-5 SM
W.O. 4107-A-SC
GoidsteiniOcean Vista
November 26, 2003
LOG OF EXPLORATORY TEST PITS
FIELD DRY
MOISTURE DENSITY DESCRIPTION
(%) (pcf)
TOPSOIL: SILTY SAND, light brown, dry, very loose.
TERRACE DEPOSITS: SILTY SAND, red brown, very
moist, loose to medium dense (denser w/depth).
Total Depth = 5'
No Groundwater Encountered
Backfilled 11-26-2003
TOPSOIL: SILTY SAND, light brown, dry, very loose.
TERRACE DEPOSITS: SILTY SAND, red brown, very
moist, loose to medium dense (denser w/depth).
Total Depth= 5'
No Groundwater Encountered
Backfilled 11-26-2003
PLATE B-2
TEST SAMPLE
PITNO. DEPTH GROUP DEPTH
(ft.) SYMBOL (ft.)
TP-5 0-1 SM
1-5 SM
W.O. 4107-A-SC
Goldstein/Ocean Vista
November 26, 2003
LOG OF EXPLORATORY TEST PITS
FIELD DRY
MOISTURE DENSITY DESCRIPTION
(%) (pcf)
TOPSOIL: SIL TY SAND, light brown, dry, very loose.
TERRACE DEPOSITS: SIL TY SAND, red brown, very
moist, loose to medium dense (denser w/depth).
Total Depth= 5'
No Groundwater Encountered
Backfilled 11-26-2003
PLATE 8-3
APPENDIX C
LABORATORY DATA
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EARTHQUAKE RECURRENCE CURVE
Ocean Vista
100
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3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0
Magnitude (M)
W.O. 4107-A-SC Plate C-1
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PROBABILITY OF EXCEEDANCE
CAMP. & BOZ. (1997 Rev.) SR 1
100
90
80
70
60
50
40
30
20
10
I •I I • I
25 yrs 50 yrs
I ■ I I T I
75 rs 100 rs
0.00 0.25 0.50 0. 75 1.00 1.25 1.50
Acceleration (g)
W.O. 4107-A-SC Plate C-2
:e p
~ ....
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RETURN PERIOD vs. ACCELERATION
CAMP. & BOZ. (1997 Rev.) SR 1
-
~ 100000 / --en
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0.00 0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (Q)
APPENDIX D
GENERAL EARTHWORK AND GRADING GUIDELINES
GENERAL EARTHWORK AND GRADING GUIDELINES
General
These guidelines present general procedures and requirements for earthwork and grading
as shown on the approved grading plans, including preparation of areas to filled, placement
of fill, installation of subdrains and excavations. The recommendations contained in the
geotechnical report are part of the earthwork and grading guidelines and would supercede
the provisions contained hereafter in the case of conflict. Evaluations performed by the
consultant during the course of grading may result in new recommendations which could
supersede these guidelines or the recommendations contained in the geotechnical report.
The contractor is responsible for the satisfactory completion of all earthwork in accordance
with provisions of the project plans and specifications. The project soil engineer and
engineering geologist (geotechnicar consultant) or their representatives should provide
observation and testing services, and geotechnical consultation during the duration of the
project.
EARTHWORK OBSERVATIONS AND TESTING
Geotechnical Consultant
Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer
and engineering geologist) should be employed for the purpose of observing earthwork
procedures and testing the fills for conformance with the recommendations of the
geotechnical report, the approved grading plans, and applicable grading codes and
ordinances.
The geotechnical consultant should provide testing and observation so that determination
may be made that the work is being accomplished as specified. It is the responsibility of
the contractor to assist the consultants and keep them apprised of anticipated work
schedules and changes, so that they may schedule their personnel accordingly.
All clean-outs, prepared ground to receive fill, key excavations, and subdrains should be
observed and documented by the project engineering geologist and/or soil engineer prior
to placing and fill. It is the contractors's responsibility to notify the engineering geologist and
soil engineer when such areas are ready for observation.
Laboratory and Field Tests
Maximum dry density tests to determine the degree of compaction should be performed in
accordance with American Standard Testing Materials test method ASTM designation
D-1557-78. Random field compaction tests should be performed in accordance with test
method ASTM designation D-1556-82, D-2937 or D-2922 and D-3017, at intervals of
approximately 2 feet of fill height or every 100 cubic yards of fill placed. These criteria
would vary depending on the soil conditions and the size of the project. The location and
frequency of testing would be at tch,e* di§Pfet}c>n Qf the geotechnical consultant.
tt'tW'i1C~ri'f?~t)fyf ~~1: ~1 k 1t:t17:/(
Contractor's Responsibility
All clearing, site preparation, and earthwork performed on the project should be conducted
by the contractor, with observation by geotechnical consultants and staged approval by the
governing agencies, as applicable. It is the contractor's responsibility to prepare the ground
surface to receive the fill, to the satisfaction of the soil engineer, and to place, spread,
moisture condition, mix and compact the fill in accordance with the recommendations of
the soil engineer. The contractor should also remove all major non-earth material
considered unsatisfactory by the soil engineer.
It is the sole responsibility of the contractor to provide adequate equipment and methods
to accomplish the earthwork in accordance with applicable grading guidelines, codes or
agency ordinances, and approved grading plans. Sufficient watering apparatus and
compaction equipment should be provided by the contractor with due consideration for the
fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical
consultant, unsatisfactory conditions such as questionable weather, excessive oversized
rock, or deleterious material, insufficient support equipment, etc., are resulting in a quality
of work that is not acceptable, the consultant will inform the contractor, and the contractor
is expected to rectify the conditions, and if necessary, stop work until conditions are
satisfactory.
During construction, the contractor shall properly grade all surfaces to maintain good
drainage and prevent ponding of water. The contractor shall take remedial measures to
control surface water and to prevent erosion of graded areas until such time as permanent
drainage and erosion control measures have been installed.
SITE PREPARATION
All major vegetation, including brush, trees, thick grasses, organic debris, and other
deleterious material should be removed and disposed of off-site. These removals must be
concluded prior to placing fill. Existing fill, soil, alluvium, colluvium, or rock materials
determined by the soil engineer or engineering geologist as being unsuitable in-place
should be removed prior to fill placement. Depending upon the soil conditions, these
materials may be reused as compacted fills. Any materials incorporated as part of the
compacted fills should be approved by the soil engineer.
Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic
tanks, wells, pipelines, or other structures not located prior to grading are to be removed or
treated in a manner recommended by the soil engineer. Soft, dry, spongy, highly fractured,
or otherwise unsuitable ground extending to such a depth that surface processing cannot
adequately improve the condition should be overexcavated down to firm ground and
approved by the soil engineer before compaction and filling operations continue.
Overexcavated and processed soils which have been properly mixed and moisture
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pgi
Appendix D
Page 2
conditioned should be re-compacted to the minimum relative compaction as specified in
these guidelines.
Existing ground which is determined to be satisfactory for support of the fills should be
scarified to a minimum depth of 6 inches or as directed by the soil engineer. After the
scarified ground is brought to optimum moisture content or greater and mixed, the materials
should be compacted as specified herein. If the scarified zone is grater that 6 inches in
depth, it may be necessary to remove the excess and place the material in lifts restricted
to about 6 inches in compacted thickness.
Existing ground which is not satisfactory to support compacted fill should be overexcavated
as required in the geotechnical report or by the on-site soils engineer and/or engineering
geologist. Scarification, disc harrowing, or other acceptable form of mixing should continue
until the soils are broken down and free of large lumps or clods, until the working surface
is reasonably uniform and free from ruts, hollow, hummocks, or other uneven features
which would inhibit compaction as described previously.
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical),
the ground should be stepped or benched. The lowest bench, which will act as a key,
should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material,
and approved by the soil engineer and/or engineering geologist. In fill over cut slope
conditions, the recommended minimum width of the lowest bench or key is also 15 feet
with the key founded on firm material, as designated by the Geotechnical Consultant. As
a general rule, unless specifically recommended otherwise by the Soil Engineer, the
minimum width of fill keys should be approximately equal to ½ the height of the slope.
Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable
material. Benching may be used to remove unsuitable materials, although it is understood
that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered
for unsuitable materials in excess of 4 feet in thickness.
All areas to receive fill, including processed areas, removal areas, and the toe of fill
benches should be observed and approved by the soil engineer and/or engineering
geologist prior to placement of fill. Fills may then be properly placed and compacted until
design grades (elevations) are attained.
COMPACTED FILLS
Any earth materials imported or excavated on the property may be utilized in the fill
• provided that each material has been determined to be suitable by the soil engineer. These
materials should be free of roots, tree branches, other organic matter or other deleterious
materials. All unsuitable materials should be removed from the fill as directed by the soil
engineer. Soils of poor gradation, undesirable expansion potential, or substandard strength
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pgi
Appendix D
Page 3
characteristics may be designated by the consultant as unsuitable and may require
blending with other soils to serve as a satisfactory fill material.
Fill materials derived from benching operations should be dispersed throughout the fill area
and blended with other bedrock derived material. Benching operations should not result
in the benched material being placed only within a single equipment width away from the
fill/bedrock contact.
Oversized materials defined as rock or other irreducible materials with a maximum
dimension greater than 12 inches should not be buried or placed in fills unless the location
of materials and disposal methods are specifically approved by the soil engineer.
Oversized material should be taken off-site or placed in accordance with recommendations
of the soil engineer in areas designated as suitable for rock disposal. Oversized material
should not be placed within 10 feet vertically of finish grade (elevation) or within 20 feet
horizontally of slope faces.
To facilitate future trenching, rock should not be placed within the range of foundation
excavations, future utilities, or underground construction unless specifically approved by
the soil engineer and/or the developers representative.
If import material is required for grading, representative samples of the materials to be
utilized as compacted fill should be analyzed in the laboratory by the soil engineer to
determine its physical properties. If any material other than that previously tested is
encountered during grading, an appropriate analysis of this material should be conducted
by the soil engineer as soon as possible.
Approved fill material should be placed in areas prepared to receive fill in near horizontal
layers that when compacted should not exceed 6 inches in thickness. The soil engineer
may approve thick lifts if testing indicates the grading procedures are such that adequate
compaction is being achieved with lifts of greater thickness. Each layer should be spread
evenly and blended to attain uniformity of material and moisture suitable for compaction.
Fill layers at a moisture content less than optimum should be watered and mixed, and wet
fill layers should be aerated by scarification or should be blended with drier material.
Moisture condition, blending, and mixing of the fill layer should continue until the fill
materials have a uniform moisture content at or above optimum moisture.
After each layer has been evenly spread, moisture conditioned and mixed, it should be
uniformly compacted to a minimum of 90 percent of maximum density as determined by
ASTM test designation, D-1557-78, or as otherwise recommended by the soil engineer.
Compaction equipment should be adequately sized and should be specifically designed
for soil compaction or of proven reliability to efficiently achieve the specified degree of
compaction.
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pgi
Appendix D
Page4
Where tests indicate that the density of any layer of fill, or portion thereof, is below the
required relative compaction, or improper moisture is in evidence, the particular layer or
portion shall be re-worked until the required density and/or moisture content has been
attained. No additional fill shall be placed in an area until the last placed lift offill has been
tested and found to meet the density and moisture requirements, and is approved by the
soil engineer.
Compaction of slopes should be accomplished by over-building a minimum of 3 feet
horizontally, and subsequently trimming back to the design slope configuration. Testing
shall be performed as the fill is elevated to evaluate compaction as the fill core is being
developed. Special efforts may be necessary to attain the specified compaction in the fill
slope zone. Final slope shaping should be performed by trimming and removing loose
materials with appropriate equipment. A final determination offill slope compaction should
be based on observation and/or testing of the finished slope face. Where compacted fill
slopes are designed steeper tha_n 2:1 (horizontal to vertical), specific material types, a
higher minimum relative compaction, and special grading procedures, may be
recommended.
If an alternative to over-building and cutting back the compacted fil I slopes is selected, then
special effort should be made to achieve the required compaction in the outer 1 O feet of
each lift of fill by undertaking the following:
1. An extra piece of equipment consisting of a heavy short shanked sheepsfoot should
be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The
sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend
out over the slope to provide adequate compaction to the face of the slope.
2. Loose fill should not be spilled out over the face of the slope as each lift is
compacted. Any loose fill spilled over a previously completed slope face should be
trimmed off or be subject to re-rolling.
3. Field compaction tests will be made in the outer (horizontal) 2 to 8 feet of the slope
at appropriate vertical intervals, subsequent to compaction operations.
4. After completion of the slope, the slope face should be shaped with a small tractor
and then re-rolled with a sheepsfoot to achieve compaction to near the slope face.
Subsequent to testing to verify. compaction, the slopes should be grid-rolled to
achieve compaction to the slope face. Final testing should be used to confirm
compaction after grid rolling.
5. Where testing indicates less than adequate compaction, the contractor will be
responsible to rip, water, mix and re-compact the slope material as necessary to
achieve compaction. Additional testing should be performed to verify compaction.
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pgi
Appendix D
Page 5
6. Erosion control and drainage devices should be designed by the project civil
engineer in compliance with ordinances of the controlling governmental agencies,
and/or in accordance with the recommendation of the soil engineer or engineering
geologist.
SUBDRAIN INSTALLATION
Subdrains should be installed in approved ground in accordance with the approximate
alignment and details indicated by the geotechnical consultant. Subdrain locations or
materials should not be changed or modified without approval of the geotechnical
consultant. The soil engineer and/or engineering geologist may recommend and direct
changes in subdrain line, grade and drain material in the field, pending exposed conditions.
The location of constructed subdrains should be recorded by the project civil engineer.
EXCAVATIONS
Excavations and cut slopes should be examined during grading by the engineering
geologist. If directed by the engineering geologist, further excavations or overexcavation
and re-filling of cut areas should be performed and/or remedial grading of cut slopes should
be performed. When fill over cut slopes are to be graded, unless otherwise approved, the
cut portion of the slope should be observed by the engineering geologist prior to placement
of materials for construction of the fill portion of the slope.
The engineering geologist should observe all cut slopes and should be notified by the
contractor when cut slopes are started. If, during the course of grading, unforeseen adverse
or potential adverse geologic conditions are encountered, the engineering geologist and
soil engineer should investigate, evaluate and make recommendations to treat these
problems. The need for cut slope buttressing or stabilizing should be based on in-grading
evaluation by the engineering geologist, whether anticipated .or not.
Unless otherwise specified in soil and geological reports, no cut slopes should be
excavated higher or steeper than that allowed by the ordinances of controlling
governmental agencies. Additionally, short-term stability of temporary cut slopes is the
contractors responsibility.
Erosion control and drainage devices should be designed by the project civil engineer and
should be constructed in compliance with the ordinances of the controlling governmental
agencies, and/or in accordance with the recommendations of the soil engineer or
engineering geologist.
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pgi
Appendix D
Page6
COMPLETION
Observation, testing and consultation by the geotechnical consultant should be conducted
during the grading operations in order to state an opinion that all cut and filled areas are
graded in accordance with the approved project specifications.
After completion of grading and after the soil engineer and engineering geologist have
finished their observations ofthe work, final reports should be submitted subject to review
by the controlling governmental agencies. No further excavation or filling should be
undertaken without prior notification of the soil engineer and/or engineering geologist.
All finished cut and fill slopes should be protected from erosion and/or be planted in
accordance with the project specifications and/or as recommended by a landscape
architect. Such protection and/or planning should be undertaken as soon as practical after
completion of grading.
JOB SAFETY
General
At GeoSoils, Inc. (GSI) getting the job done safely is of primary concern. The following is
the company's safety considerations for use by all employees on multi-employer
construction sites. On ground personnel are at highest risk of injury and possible fatality
on grading and construction projects. GSI recognizes that construction activities will vary
on each site and that site safety is the prime responsibility of the contractor; however,
everyone must be safety conscious and responsible at all times. To achieve our goal of
avoiding accidents, cooperation between the client, the contractor and GSI personnel must
be maintained.
In an effort to minimize risks associated with geotechnical testing and observation, the
following precautions are to be implemented for the safety of field personnel on grading and
construction projects:
Safety Meetings: GSI field personnel are directed to attend contractors regularly
scheduled and documented safety meetings.
Safety Vests: Safety vests are provided for and are to be worn by GSI personnel at
all times when they are working in the field.
Safety Flags: Two safety flags are provided to GSI field technicians; one is to be
affixed to the vehicle when on site, the other is to be placed atop the
spoil pile on all test pits.
Mr. Bernard Goldstein Appendix D
File:e:\wp9\4100\4107a.pgi Page 7
Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing
amber beacon, or strobe lights, on the vehicle during all field testing.
While operating a vehicle in the grading area, the emergency flasher
on the vehicle shall be activated.
In the event that the contractor1s representative observes any of our personnel not following
the above, we request that it be brought to the attention of our office.
Test Pits Location. Orientation and Clearance
The technician is responsible for selecting test pit locations. A primary concern should be
the technicians1s safety. Efforts will be made to coordinate locations with the grading
contractors authorized representative, and to select locations following or behind the
established traffic pattern, preferably outside of current traffic. The contractors authorized
representative (dump man, operator, supervisor, grade checker, etc.) should direct
excavation of the pit and safety during the test period. Of paramount concern should be the
soil technicians safety and obtaining enough tests to represent the fill.
Test pits should be excavated so that the spoil pile is placed away form oncoming traffic,
whenever possible. The technician1s vehicle is to be placed next to the test pit, opposite the
spoil pile. This necessitates the fill be maintained in a driveable condition. Alternatively,
the contractor may wish to park a piece of equipment in front of the test holes, particularly
in small fill areas or those with limited access.
A zone of non-encroachment should be established for all test pits. No grading equipment
should enter this zone during the testing procedure. The zone should extend approximately
50 feet outward from the center of the test pit. This zone is established for safety and to
avoid excessive ground vibration which typically decreased test results.
When taking slope tests the technician should park the vehicle directly above or below the
test location. If this is not possible, a prominent flag should be placed at the top of the
slope. The contractor1s representative should effectively keep all equipment at a safe
operation distance (e.g., 50 feet) away from the slope during this testing.
The technician is directed to withdraw from the active portion of the fill as soon as possible
following testing. The technician1s vehicle should be parked at the perimeter of the fill in a
highly visible location, well away from the equipment traffic pattern. The contractor should
inform our personnel of all changes to haul roads, cut and fill areas or other factors that may
affect site access and site safety.
In the event that the technicians safety is jeopardized or compromised as a result of the
contractors failure to comply with any of the above, the technician is required, by company
policy, to immediately withdraw and notify his/her supervisor. The grading contractors
representative will eventually be contacted in an effort to effect a solution. However, in the
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pgi
Appendix D
Page 8
interim, no further testing will be performed until the situation is rectified. Any fill place 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 brings this to his/her attention and notify
this office. Effective communication and coordination between the contractors
representative and the soils technician is strongly encouraged in order to implement the
above safety plan.
Trench and Vertical Excavation
It is the contractor's responsibility to provide safe access into trenches where compaction
testing is needed.
Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or
deeper unless shored or laid back; 2) displays any evidence of instability, has any loose
rock or other debris which could fall into the trench; or 3) displays any other evidence of any
unsafe conditions regardless of depth.
All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters,
should be shored or laid back. Trench access should be provided in accordance with CAL
OSHA and/or state and local standards. Our personnel are directed not to enter any trench
by being lowered or "riding down" on the equipment.
If the contractor fails to provide safe access to trenches for compaction testing, our company
policy requires that the soil technician withdraw and notify his/her supervisor. The
contractors representative will eventually 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.
If GSI personnel become aware of anyone working beneath an unsafe trench wall or
vertical excavation, we have a legal obligation to put the contractor and owner/developer
on notice to immediately correct the situation. If corrective steps are not taken, GSI then has
an obligation to notify CAL-OSHA and/or the proper authorities.
Mr. Bernard Goldstein
File:e:\wp9\4100\4107a.pgi
Appendix D
Page9
TRANSITION LOT DETAIL
CUT LOT (MATERIAL TYPE TRANSITION}
-----------------~
PAD GRADE
COMPACTED FILL
1/\\\~ 3 MINIMUM•
UNWEATHERED BEDROCK OR APPROVED MATERIAL
TYPICAL BENCH ING
CUT-FILL LOT (DAYLIGHT TRANSITION)
NATURAL GRADE ~~.,co~~\JI-.\. MUM __,,.._ ~~\ .,.._._...
PAO GRADE .,,,,-_~~\.'f:,.
--_.;._;.._;;;;,_......._ ______ ~~ OVEREX·CAVATE···
COMPACTED FILL ~ • OMPACT
~ co'-\.\J ~\°X//(\Y-1/ 3' MINIMUM*
___.-----• ~"-"· ~o
~~"'o
NWEATHERED BEDROCK OR APPROVED MATERIAL
CAL BENCHING
NOTE: * DEEPER OVEREXCAVATION MAY BE RECOMMENDED BY THE SOILS ENGINEER
AND/OR ENGINEERING GEOLOGIST IN STEEP CUT-FILL TRANSITION AREAS.
PLATE EG-11"
TEST PIT SAFETY 01~,GRAM
so FEET
FLA~-SPOIL
PILE
SIDE VIEW
( NOT TO SCALE )
TOP VEW
100 FEET
i I ...
Hf LL.
0 an
t-FLAG
/
➔
APPROXlMA TE C9CTER ~
CF "TEST PtT C
It)
H
l NOT TO SCALE }
SO FEET -
PLATE EG-16
~
u
'
i ---------------
-
----
I
---
40'-0'1 t of Rod
/
/
/
/
/
/
/
/
/
/
9 _(J)' / ----------------1.~====r-a::::...'-...,..,..-~~~-~--~ ~-'--,-
"-
I -___
10'-011 Ext.
S.YSB.
\
~
--------\: -------7
-~----
RIVERSIDE CO.
ORANGE CO.
SAN DIEGO CO.
LEGEND
GAR.FIELD S ·T R E E
/
/ / Line of (E) Curb,
/ / l~p-U.ON. A
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COMMO/'-1 AR;::A
FOR PUD LOTS -
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R E E T
TEST PlT LOCATION MAP cz:I TP-5 Approximate location of exploratory test pit'
Plate 1 ·SITE PLAN
W.0. 41Q7~A.:SC • DATE 12/03 SCALE
PL
1·
I $'-0"
S.Y.SB.
t~p-
UO.N.
G ' G "'
DA.TA Si-iOHN ON Tl-ilS PLAN
OBTAINED FROM
NORi-l
INFORMATION PROVIDED BY
Tl-iE CITY OF CARLSBAD MAP
NO.203-14 Sl-iT. I OF 2
G.C. 'vERIFY ALL EXISTiNG
CONDITIONS
30'-0" Max Height
'Jp,:,,er Floor
Main Floor
Basement
S'-!111
lnt.
5.Y.So.
PL
SCl-i::'1ATIC SECTION
I 1-.3:v~ rev!e~ed llie~e com,1.ruc.'.lon dOCL.ll!lenl&
.!ll"O h<l;v$ -'!'prOYe:::I 1hl:,lr C:Ol'ILel'll~ .!le ln.::l11Cilr1_g
all or fr1l:I de519r1 <1spe::t.s I hdd p-e:vbuBI~
authorized, I 11ncier~tcJnci ~ proJec:L i--ii!I be
ccmtruct.-ed ,u &pcclfled ~ 1.he6e ,::c,,~lr-ucuon
document.~.
REVISIONS By
t
101-011 = 111
~------1 Drawn
by: RRR
Job No.
--~---~Sheet
C-2
Of Sh eels