HomeMy WebLinkAboutCT 01-06; CASA LAGUNA; GEOTECHNICAL REPORT; 2000-08-24^ AGRA
ENGINEEKING GIOSAL SOLUTIONS
GEOTECHNICAL REPORT
670 LAGUNA DRIVE CONDOMINIUMS
CARLSBAD, CAUFORNIA
Submitted To:
RESG, INC.
31225 LA BAYA DRIVE, SUITE 103
WESTLAKE VILLAGE, CALIFORNIA 92008
Submitted By:
AGRA EARTH & ENVIRONMENTAL
16760 WEST BERNARDO DRIVE
SAN DIEGO, CALIFORNIA 92127-1904
August 24, 2000
Job No. 0-252-104400
AGRA Earth &
Environmental, Inc.
16760 W. Bernardo Dr.
San Diego, CA 92127
Tei (858) 487-2113 - D'-*
Fax (858) 487-2357
®
^ AGRA
ENGINEERING GLOBAL SOLUTIONS
August 24, 2000
Job No. 0-252-104400
AGRA Earth &
Environmental, Inc.
16760 W. Bernardo Dr.
San Diego. CA 92127
Tel (858) 487-2113
Fax (858) 487-2357
Mr. Michael Roletti
RESG, Inc.
31225 La Baya Drive, Suite 103
WestlakeVillage,CA 91362
RE: GEOTECHNICAL REPORT
LAGUNA CARLSBAD CONDOMINIUMS
670 LAGUNA DRIVE
CARLSBAD, CALIFORNIA
Dear Mr. Roletti:
In accordance with your request and authorization, AGRA Earth & Environmental, Inc. (AGRA),
an AMEC company, has conducted a geotechnical investigation forthe proposed condominium
development at 670 Laguna Drive in Carisbad, Califomia (Figure 1, Site Location Map). Based on
the results of AGRA's study, it is our opinion that the development of the site is feasible provided
the recommendations presented, herein, are incorporated into the design and construction ofthe
proposed improvements. The accompanying report presents a summary of our current findings
and provides geotechnical conclusions and recommendations relative to the proposed site
development.
We appreciate this opportunity to be of service. If you have any questions regarding AGRA's
report, please do not hesitate to contact the undersigned.
Respectfully submitted,
AGRA Earth & Environmental, Inc.
[Joseph Gf. Franzone, RCE
ietyising Engineering
JGF/TMM/drs
Distribution: (6) Addressee
avid L. Perry. CEG, 2040 ^
enior Engineering Geologist
\\OscalcoVpublic\02S2104400 RESG UgunaO(\02SZ104400 RESG Uguna OriveCailsbadConda 08 24 OO.rpt.wpd
Mr. Michael Roletti
RESG, Inc. August 24, 2000
Project No. 0-252-104400 Page (i)
TABLE OF CONTENTS
Page
1.0 INTRODUCTION 1
1.1 PURPOSE AND SCOPE 1
1.2 SITE LOCATION AND DESCRIPTION 1
1.3 PROPOSED DEVELOPMENT 3
2.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING 3
3.0 SUMMARY OF GEOTECHNICAL CONDITIONS 5
3.1 GEOLOGIC SETTING 5
3.2 SITE-SPECIFIC GEOLOGY 5
3.2.1 Undocumented Fill Soils 5
3.2.2 Colluvium 5
3.2.3 Terrace Deposits 6
3.2.4 Santiago Fonnation 6
3.3 GROUNDWATER 6
4.0 FAULTING AND SEISMICITY 6
4.1 FAULTING 6
4.2 SEISMICITY 8
4.2.1 Lurching and Shallow Ground Rupture 9
4.2.2 Liquefaction and Dynamic Settlement 9
4.2.3 Tsunamis and Seiches 9
4.2.4 UBC Criteria g
5.0 CONCLUSIONS 10
6.0 RECOMMENDATIONS 11
6.1 GENERAL EARTHWORK 11
6.1.1 Site Preparation 11
6.1.2 Removals 11
6.1.3 Structural, Fills 12
6.2 PRELIMINARY FOUNDATION DESIGN 12
6.2.1 Post-tensioned Foundation Design 12
6.2.2 Conventional Foundation Design 14
6.2.3 Moisture Conditioning 15
6.3 SETTLEMENT ' 16
6.4 LATERAL EARTH PRESSURES AND RETAINING
WALL DESIGN CONSIDERATIONS 16
6.5 PRELIMINARY PAVEMENT DESIGN 17
^ AGRA
®
Mr. Michael RoletU
RESG, Inc. August 24. 2000
Project No. 0-252-104400 Page (1)
1.0 INTRODUCTION
1.1 PURPOSE AND SCOPE
This report presents the results of our geotechnical study forthe proposed residential development
ofthe approximate 1%-acre property at 670 Laguna Drive in Carisbad, Califomia (Rgure 1). The
purpose of our study was to evaluate the existing significant geotechnical conditions present at
the site and to provide preliminary conclusions and geotechnical recommendations relative to the
proposed development Our scope of services induded:
Review of available pertinent, reference documents regarding the geotechnical conditions
at the site.
A geologic/geotechnical reconnaissance of the site.
Excavation of five exploratory borings across the site. (Underground Sen/ice Alert was
contacted prior to drilling.)
Geologic logging of the borings.
Obtained representative soil samples during drilling for laboratory testing and analysis
purposes, as appropriate.
Geotechnical analysis of data obtained.
Preparation of this report addressing the geotechnical conditions at the site with respect
to the proposed development.
I SITE LOCATION AND DESCRIPTION
The project site, 670 Laguna Drive, is located northwest of the intersection of Laguna Drive and
Madison Street in Carisbad, Califomia (Figure 1). The site is composed of Lots 8 and 9 of Block
223, Map 2492, Buena Vista Gardens. Currently, a single-family residence occupies the property
and is located in the southwestem portion of the property. A wooden fence approximately
delineates the property boundary in the backyard area. A chain fence with a locked gate divides
the front yard from the backyard. The surface of the site is relatively level and partially covered
with dry grasses and scattered shrubs and trees. The site surface elevation is about 40 feet above
mean sea level (MSL).
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Mr. Michael Roletti
RESG, Inc.
Project No. 0-252-104400 August 24, 2000
Page Oi)
TABLE OF CONTENTS
(continued)
7.0
8.0
Page
6.6 CONTROL OF SURFACE WATER AND DRAINAGE CONTROL .... 19
6.7 SOIL CORROSIVITY ig
6.8 FLATWORK RECOMMENDATIONS 20
CONSTRUCTION OBSERVATION, LIMITATIONS, AND PLAN REVIEW 20
REFERENCES 21
TABLES
Table 1 - Seismic Parameters for Active Faults 8
FIGURES
Figure 1 - Vicinity Map 2
Figure 2 - Boring Location Map 4
Figure 3 - Fault Map 7
APPENDICES
Appendix A Boring Logs
Appendix B Laboratory Data Analysis
Appendix C General Earthwori< and Grading Specifications for Rough Grading
^ AGRA
Mr. Michael Roletti
RESG. Inc.
Job No. 0-252-104400
August 30, 2000
Page (2)
Approximate Graphic Scale
1 in = 0.3 mi Approx. North
Reference:
Streets98, Microsoft Expedia, Version 6.0
LAGUNA CARLSBAD CONDOMINIUMS
670 Laguna Drive
CARLSBAD, CALIFORNIA
Figure 1 - Vicinity Map
AGRA Engineering Global Solutions
AlF
imii j u n
Mr. Michael Roletti
RESG, Inc. August 24. 2000
Project No. 0-252-104400 Page (3)
1.3 PROPOSED DEVELOPMENT
It is our understanding that the proposed development will include minor grading and the
construction of a 24-unit condominium complex. Condominium units are planned to be 2-story
structures. Associated concrete fIatwori<, asphalt concrete roadways/paridng, and landscaping are
also planned. Preliminary foundation design or structural loads were not provided prior to
preparation of this report.
2.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING
Subsurface exploration was perfonned on August 8, 2000. Five exploratory borings were drilled
with a hollow stem auger drill rig across the site. The approximate locations of tiie borings are
shown on Figure 2. The borings were drilled to approximately 21 feet below the ground surface.
The purpose of the exploratory borings was to evaluate the physical characteristics and
engineering properties of the on-site soils pertinent to the proposed development.
An AGRA engineer logged the exploratory borings. Representative ring and bulk samples were
obtained for laboratory testing. Relatively undisturtaed (ring) samples were obtained using a 2.5-
inch I.D. sampler driven by a 140-pound hammer falling 30 inches. SPT samples were also
obtained. Bulk samples were obtained from drill cuttings. After logging and sampling, the
excavations were backfilled with the drill cuttings.
Laboratory testing was performed on ring samples from \he borings to evaluate the in-situ moisture
and density, grain-size distiibution, shear sti-ength, potential consolidation, R-value, expansion
potential and corrosivity characteristics of tiie subsurface soils. Corrosivity testing included pH and
minimum resistivity, sulfate content, and chloride content testing. A discussion of the laboratory
tests performed and a summary of tiie laboratory test results are presented in Appendix B. In-situ
moisture and density test results performed on ring samples are provided on Uie boring logs in
Appendix A.
^ AGRA
Mr. Michael Roletti
RESG, Inc.
Job No. 0-252-104400
August 30, 2000
Page (4)
B-5
TD=21' TD=21.5';
B-3
TD=2r
Approximate Location
of Existing Residence
B-2
TD=2r
-XXXXXXXXX"
TD=2r
LAGUNA DRIVE
EXPLANATION
DRAWING NOT TO SCALE
B-5
TD=2r
XXXXX
APPROXIMATE
BORING LOCATION
with TOTAL DEPTH
WOODEN FENCE
CHAIN LINK FENCE
GATE
N
t
LAGUNA CARLSBAD CONDOMINIUMS
670 LAGUNA DRIVE
CARLSBAD, CALIFORNIA
FIGURE 2 - BORING LOCATION MAP
AGRA Eartii & Environmental
-ssnr 0-252-10*400
Mr. Michael Roletti
RESG, Inc. August 24. 2000
Project No. 0-252-104400 Page (5)
3.0 SUMMARY OF GEOTECHNICAL CONDITIONS
3.1 GEOLOGIC SETTING
The project site is situated on the coastal plain of tiie Peninsular Range Physiographic Province.
The project vicinity area is underiain by sedimentary sti'ata of Late Cretaceous, Tertiary and
Quatemary age resting unconformably on a basement rock of the Southem Califomia batholith.
Tertiary, predominantiy marine, sediments are capped by Quatemary marine and non-marine
sediments deposited on a series of coastal terraces fonning a belt along the modem shoreline.
Each marine tenrace was wave-cut during a Pleistocene sea transgression (sea-level high stand),
followed by deposition of sediments during tiie sea regression, and has undergone tectonical
uplift. Four terraces are recognized in tiie site vicinity area, with the oldest terrace occupying the
highest elevation that, reportedly, is correlated with the Linda Vista Formation. The project site is
located on the youngest terrace (at the lowest elevation). The tenrace surface is dissected by
Buena Vista Creek drainage north of tiie site.
Quatemary tenrace deposits underiying the project site consist of reddish brown, pooriy bedded,
pooriy to moderately indurated sandstone, siltstone and conglomerate (Tan and Kennedy, 1996).
These deposits unconformably overiie the Eocene-aged Santiago Formation, represented by light-
colored sandstone interiayered with siltstone and claystone.
3.2 SITE-SPECIFIC GEOLOGY
Based on our subsurface exploration and review of pertinent geologic literature and maps, the site
is underiain by undocumented fill, colluvium, terrace deposits, and the Santiago Formation. A brief
description of the geologic units encountered on the site is presented below.
3.2.1 Undocumented Fill Soils
The thickness of the fill soils appears to be up to 4 feet, as encountered in our borings.
The fill soils were generally composed of brown, loose, silty sand. Expansion testing on
this unit indicates a very low expansion potential (Appendix B).
3.2.2 Colluvium
Colluvium was encountered underiying the fill at Borings B-1 to B-4 and at Uie existing
ground surface at Boring B-5. The colluvium was encountered to depths of 7 to SYi feet
below tiie ground surface in Borings B-1, B-3, B-4, and B-5 and to a depth of
approximately 4 feet in Boring B-2. This unit generally consists of medium stiff to stiff
sandy clay.
Based on laboratory testing on one sample of the colluvium, this unit was found to have
a high expansion potential (Appendix B).
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Mr. Michael Roletti
RESG, Inc. August 24, 2000
Project No. 0-252-104400 Page (6)
3.2.3 Terrace Deposits
Terrace deposits were encountered underiying tiie colluvium. The terrace deposits were
encountered to a depth of 8 to 11 feet below Uie ground surface. This unit generally
consists of medium dense clayey sand.
3.2.4 Santiago Formation
The Santiago Fonnation was encountered underiying tiie terrace deposits and was
encountered to tiie maximum depth of each boring, or 20 to IVA feet. This unit, as
encountered, consists of weakly to moderately cemented clayey sandstone. This unit is
not anticipated to be encountered during grading.
3.3 GROUNDWATER
During our investigation, groundwater was encountered at depths ranging from 15 to I8V2 feet
below the existing ground surface. It is important to recognize that groundwater levels can
fluctuate due to rainfall, irngation and surface mn-off.
4.0 FAULTING AND SEISMICITY
4.1 FAULTING
Our discussion of faults on the site is prefaced with a discussion of Califomia legislation and
policies conceming the classification and land-use criteria associated with faults. By definition of
tiie Califomia Mining and Geology Board, an "active" fault is a fault that has had surface
displacement within Hoiocene time (about the last 11.000 years). The state geologist has defined
a "potentially active" fault as any fault considered to have been active during Quatemary time (last
1,600,000 years). This definition is used in delineating Earthquake Fault Zones as mandated by
the Alquist-Priolo Geologic Hazards Zones Act of 1972 and as subsequentiy revised in 1975.
1985, 1990, 1992. and 1994. The intent of this act is to assure that unwise urban development
and certain habitable structures do not occur across the traces of active faults. The subject site
is not included within any Earthquake Fault Zones as established by the State Geologist around
known active faults.
Our review of published and in-house geologic literature (Section 8.0) and maps indicates that
there are no known major or active faults on or in Uie immediate vicinity of Uie site. The nearest
active regional faults are the Newport-Inglewood - Rose Canyon Fault Zone. Coronado Bank Fault
and Whittier - Elsinore Fault Zone located approximately 4. 21, and 24 miles from Uie site,
respectively (see Figure 3 for regional tectonic framewori<).
% AGRA
®
Mr. Michael Roletti
RESG, Inc.
Job No. 0-252-104400
August 30, 2000
Page (7)
Mr. Michael Roletti
RESG. Inc.
Project No. 0-252-104400
August 24. 2000
Page (8)
4.2 SEISMICITY
The site can be considered to lie witiiin a seismically active region, as can all of Soutiiem
Califomia. Table 1 (below) identifies potential seismic events Uiat could be produced by Uie
maximum probable and credible earthquake events. A maximum probable earthquake is tiie
largest earthquake expected on a given fault during a specified period of time. The Califomia
Division of Mines and Geology currently uses a 63% probability of being exceeded in a 100-year
period as the criterion for establishing tiie maximum probable earthquake fora particular fault. The
maximum credible earthquake is the largest earUiquake Uiat might be expected to occur based
on Uie tectonic framework of the region as it is cunrentiy understood. Site-specific seismic
parameters induded in Table 1 are tiie distances to tiie causative faults, earthquake magnitudes,
and expected ground accelerations.
TABLE1
Seismic Parameters. For Active Faults
Fault Zone
(Seismic
Source)
Distance to
Site
(Miles)
Maximum Credible
Earthquake
Maximum Probable
Earthquake
Design
Earthquake
(g)
Fault Zone
(Seismic
Source)
Distance to
Site
(Miles)
Moment
Magnitude
Peak
Horizontal
Ground
Acceleration
(g)
Moment
Magnitude
Peak
Horizontal
Ground
Acceleration
(g)
Design
Earthquake
(g)
Rose Canyon 4 7.0 0.48 6.5 0.31
0.28 Coronado
Bank 21 7.5 0.18 6.7 0.09
0.28
Elsinore 24 7.5 0.15 6.6 0.07
0.28
As indicated in Table 1, Uie Rose Canyon Fault is the nearest to the site and is considered to be
the source of the strongest potential ground shaking. The maximum credible earthquake from the
Rose Canyon has 7.0 moment magnitude, generating peak horizontal bedrock accelerations of
0.48g at the project site. The maximum probable earthquake from the Rose Canyon Zone is
considered to have a magnitude of 6.5, generating a peak horizontal bedrock acceleration of
0.31g atthe project site. Earthquakes on other faults also could affect the site, but the estimated
earthquake effects from other faults are predicted to be less severe than those which could be
generated by Uie Rose Canyon Fault.
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Mr. Mictiael Roletti
RESG, Inc. August 24, 2000
Project No. 0-252-104400 Page (9)
From a probabilistic standpoint, the design ground motion is defined as the ground motion having
aio percent probability of being exceeded in 50 years. This ground motion Is referred to as tiie
design ground motion (UBC, 1997). The design ground motion at Uie site is predicted to be 0.28g.
The effect of seismic shaking may be mitigated by adhering to the Uniform Building Code and
state-of-the-art seismic design parameters of the Structural Engineers Assodation of Califomia
(see Section 4.2.5).
Secondary effects Uiat can be associated witti severe ground shaking following a relatively large
earthquake include ground lurching and shallow ground mpture, soil liquefaction and dynamic
settiement, seiches and tsunamis. These secondary effects of seismic shaking are discussed in
the following sections.
4.2.1 Lurching and Shallow Ground Rupture
Soil lurching refers to the rolling motion on Uie ground surface by the passage of seismic
surface waves. Effects of this nature are likely to be significant where Uie tiiickness of soft
sediments vary appreciably under stmctures. Damage to the proposed development
should not be significant since a relatively large differential colluvium/fill thickness does not
exist below the site.
4.2.2 Liquefaction and Dynamic Settlement
Liquefaction and dynamic settlement of soils can be caused by strong, vibratory motion
due to earthquakes. Both research and historical data indicate that loose, saturated,
granular soils are susceptible to liquefaction and dynamic settlement while Uie stability of
soils witii a clay content of 15 percent or more and nonsensitive clays are not adversely
affected by vibratory motion. Liquefaction is typified by a total loss of shear strength in the
affected soil layer, tiiereby causing the soil to flow as a liquid. This effect may be
manifested by excessive settlements and sand boils at the ground surface. Due to the
relatively dense and clayey nature of the colluvial soils and formational material, the
potential for liquefaction is considered to be very low at the site.
4.2.3 Tsunamis and Seiches
Based on the elevation ofthe site with respect to sea level, Uie distance between the site
and large, open bodies of water, and bamers between the site and the open ocean, the
possibility of seiches and/or tsunamis is considered to be low.
4.2.4 UBC Criteria
Geotechnical parameters for design to resist seismic forces in accordance with
Intemational Council of Building Officials procedures (UBC, 1997) are contained in Table
2.
^AGRA
Mr. Michael Roletti
RESG, Inc.
Project No. 0-252-104400
August 24, 2000
Page (10)
TABLE 2
UBC Seismic Design Parameters
UBC Table Coefficient/Factor Value
16-1 Seismic Zone Factor Z Zone 4; Z = 0.40
16-J Soil Profile Type Sc
16-Q Seismic Coefficient C, 0.40/V,
16-R Seismic Coefficient Cy 0.56/V,
16-S Near-Source Factor W, 1.0
16-T Near-Source Factor 1.15
16-U Seismic Source Type Type B
M>= 6.5; SR<2
5.0 CONCLUSIONS
Based on the results of our preliminary geotechnical evaluation of the site, it is our opinion that
the proposed development is feasible from a geotechnical standpoint, provided the foiiowing
conclusions and recommendations are incorporated into the project plans and specifications.
The following is a summary of the geotechnical factors that may affect development of the site.
• Based on our subsurface exploration and laboratory testing, the colluvial soils are
generally considered to have a high expansion potential (Appendix B) while tiie overiying
fill soils have a very low expansion potential. Removal and recompaction is anticipated to
provide a medium expansion potential belowthe stmctures. Accordingly, we recommend
the use of reinforced conventional foundations or post-tension slabs.
• Based on subsurface exploration of the fill and colluvial soils present on the site, we
anticipate that these materials should be generally rippable with conventional medium-duty
earthwori< equipment.
• Laboratory test results indicate the soils present on the site have a negligible potential for
sulfate attack on concrete. However, these soils are also considered to be severely
corrosive to ferrous metals.
• The design earthquake, having a 10 percent probability of being exceeded in 50 years, is
expected to produce a peak ground surface acceleration at the site of 0.28g.
^ AGRA
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Mr. Michael Roletti
RESG. Inc. August 24, 2000
Project No. 0-252-104400 Page (11)
• Groundwater was encountered at a depUi of 15 to 18^4 feet below the existing ground
surface during our subsurface exploration. Groundwater is not anticipated to be
encountered during site grading and constmction. Seepage should be anticipated after
episodes of precipitation or near areas of inigation. Groundwater is not expected to
significantiy impact Uie at-grade proposed development provided Uie recommendations
regarding drainage outiined in Uiis report are implemented.
• Based on our analysis, there is a very low potential for liquefaction of the on-site soils.
6.0 RECOMMENDATIONS
6.1 GENERAL EARTHWORK
Earthwork should be performed in accordance with tiie General Earthwork and Grading
Specifications in Appendix C and tiie following recommendations. The recommendations ^^Ci^CL^
contained in Appendix C are general grading specifications provided for typical grading project and
may not be stricUy applicable to this project. The spedfic recommendations contained in the text
of tills report supersede the general recommendations in Appendix C. The conti^ct with Uie ju«
earthwork contractor should be worded such Uiat it is Uie responsibility of Uie contractor to place
the fill properiy and in accordance with the recommendations of Uiis report and the specification CA/WC )rv
in Appendix C, not withstanding the testing and observation of the geotechnical consultant.
6.1.1 Site Preparation
Following demolition ofthe stiuctures that are to be removed, the surface ofthe site should
be stripped to remove existing vegetation, debris, other deleterious materials and
pavements. Existing irrigation, drainage and utility lines, or other existing subsurface
stmctures which are not utilized, should be removed, destroyed or abandoned in
compliance with current regulations. If a pipe which extends off Uie property is to be
abandoned, it should be properiy capped at the project boundary. Holes resulting from
removal of buried obstmctions such as foundations or below-grade stmctures that extend
below finished site grades should be filled with properiy compacted soil under the
obsen/ation and testing of the geotechnical engineer Mixing of different types of on-site
soils or mixing of soil and lime (Section 6.2.2) to reduce expansion potential should be
perfonned by appropriate equipment tiiat provides thorough mixing without clay clumps.
Mixing should be performed under the observation and testing of the geotechnical
consultant.
6.1.2 Removals
Based on laboratory testing, the colluvial soils have a high expansion potential and tiie fill
soils have a very low expansion potential. "Mixing" of tiiese soils is recommended to create
a fill blanket of moderate expansion potential (less than 90 per UBC 18-2). Import soil, if
^ AGRA
Mr. Michael Roletti
RESG, Inc. August 24, 2000
Project No. 0-252-104400 Page (12)
necessary, should be granular soil witii an expansion index (El) less Uian 50. The depth
of recommended removals across Uie site is a minimum riapth nf d feet hpi"w Uie
proposed pavement or slab subgrade elevation. Removals should extend at least 5 feet
bevond the perimeter of the foundation footprints. All excavation/removal bottoms should
expose firm and competent material and all bottoms should be observed by the
geotechnical engineer. Mixing of on-site soil (to a depth of 3 feet below stmctures and 2
feet below the flatwori< and pavement) with 4% quick lime is recommended for
conventional foundations (Section 6.2.2).
6.1.3 Structural Fills
The on-site surficial soils are generally suitable for use as compacted fill. Import soils
should be tested by tiie geotechnical consultant prior to site delivery. Fills placed within
4 feet of finish pad grade should consist of soils with an expansion potential less than 90
based on UBC Standardi8-2 and with a maximum size less than 8 inches. Asphalt
concrete and concrete should not be placed below the water-tabte-ocwithin 5 feeLof pad
grade. Asphajt_and-coacrete shou}d._bej3£gken up_jQ_a_maxiaauo3-sizft otAJnches-in
stixictural fills. The area to receive fill should be scarified to a minimum depth of 6 inches,
brought to a moisture content of.a2Ji-above optimum moisture contenLand recompacted
to at least 90 percent relative compaction (based on Modified Proctor, ASTM D1557). The
optimum lift thickness to produce a unifonnly compacted fill will depend on the type and
size of compaction equipment used. In general, fill should be placed in unifonn lifts not
exceeding 8 inches in loose tiiickness. Fill soils should be placed at a minimum of 90
percent relative compaction (based on ASTM D1557) and moisture conditioned to 3
percent above optimum moisture content. Placement and compaction of fill should be
performed in accordance with the local grading ordinance under the observation and
testing of the geotechnical consultant.
6.2 PRELIMINARY FOUNDATION DESIGN
We anticipate that moderately expansive soils will be at the proposed bottom of footing elevation.
AGRA recommends that either-a-conventional-or a postrtension foundatiorrsystem-be-used-to
support.Uie proposed stmctures. Separate foundation design parameters are presented in this
section for both options.
6.2.1 Post-tensioned Foundation Design
We understand the proposed residential stmctures will be one- to two-story, of wood-frame
constmction. Based on the moderately expansive soil anticipated at the proposed grade,
we recommend a post-tensioned slab-on-grade floor system to provide a better perfonning
foundation system to reduce the potential for expansive-soil related distress. Foundations
and slabs should be designed by a stmctural engineer in accordance with stmctural
^ AGRA
Mr. Michael Roletti
RESG, Inc.
Project No. 0-252-104400
August 24. 2000
Page (13)
considerations and the following recommendations. These recommendations assume that
the soils in tiie upper 4 feet of finish grade will have a moderate potential for expansion (an
expansion index less than 90 per UBC Standard 18-2). The actual expansion potential of
the finish grade soils of tiie building pads should be evaluated upon completion of the fine-
grading operations so that final geotechnical design recommendations can be made.
We recommend that post-tensioned slabs be designed in accordance with the following
design parameters presented in Table 3 and the criteria ofthe 1997 edition of Uie Uniform
Building Code (ICBO, 1997).
TABLE 3
Post-tensioned Slab Design Recommendations
Expansion Index (UBC 18-I-B)
Design Criteria Moderate
(50 to 90)
Edge Moisture
Variation, e„
Center Lift:
Edge Lift
5.5 feet
2.5 feet
Differential Swell, y„ Center Lift:
Edge Lift:
3.0 inches
1.0 inches
Minimum Perimeter Footing Embedment 18 inches
The post-tensioned slabs shouid be designed in accordance with the recommendations
of the stmctural engineer.
Slabs should be underiain by a 2-inch layer of dean sand (sand equivalent greater than
30) to aid in concrete curing, which is underiain by a 10-mil (or heavier) moisture bamer,
which is in tum underiain by 2 inches of clean sand to act as a capillary break. All
penetrations through the moisture barrier and laps should be sealed. Slab subgrade soils
should be presoaked in accordance with the recommendations presented in Section 6.2.3.
Our experience indicates tiiat use of reinforcement in slabs and foundations can generally
reduce the potential for drying and shrinkage cracking. However, some cracking should
be expected as the concrete cures. Minor cracking is considered nonmal; however, it is
often aggravated bv a hich water/cement ratio, high coricr.ete-tempecatme^at tiie time of
placement, srnajl nominaLaggregate-size, and rapidrnoisture loss.dueJtahflt_dryrand/or
windy weather conditionsjlt£ingj3lacement,and^ Cracking due to temperature and
moisture"fiu~ctuations can also be expected. Theuse^tio\fi(Lslump_coiicrate (npt^exceeding
4 inches at the tirne of_placement) can reduce the_potential. for.shrinkage-cracking.
Moisture barrierscan retard, but not eliminate vapor movement from the underiying soils
up through the slab. We recommend Uiat the floor-covering contractor test Uie moisture
^ AGRA
®
Mr. Michael Roletti
RESG, Inc. August 24. 2000
Project No. 0-252-104400 Page (14)
vapor flux rate prior to attempting application of moisture-sensitive flooring. "Breathable"
floor covering or spedal slab sealants should be considered if the vapor flux i ales di e I ligfT.
Floor covering manufacturers should be consulted for specific recommendations.
To reduce the potential for future cosmetic distress due to concrete shrinkage cracks and
minor soil movement, AGRA recommends Uiat any proposed inflexible floor coverings,
such as ceramic tile or decorative stone, be installed on a 1%-insiiltiick, xA/ire-reiqfnrreri
mnrtar hgd nyen-a-dea-vaae membrane as recommended by Jhe_Cjecarmc-XUe-lRstitute.
The purpose of the mortar bed and cleavage membrane is to allow minor slab movement
under an inflexible floor covering without significant impact to tiie covering. Altemate
means of providing the same level of protection may also be considered if recommended
by a qualified tile contractor. Flexible joint material should be used where crack-sensitive
flooring overiies concrete joints.
6.2.2 Conventional Foundation Design
We anticipate that soils of moderate expansion potential will exist after site grading.
Subgrade should be treated with lime (see Section 6.1.2) for this option. Footings bearing
in properiy compacted, stmctural fill should have a minimum depth of 18 inches belowthe
lowest adjacent compacted soil grade. At a depth of 18 inches, footings may be designed
using an allowable soil-bearing value of 2,000 pounds per square foot (psf). This value
may be increased by one-tiiird for loads of short duration including wind or seismic forces.
Continuous footings should be reinforced witii a minimum reinforcement of four No. 4
rebars, two near the top and two near the bottom of the footing. Isolated-spread footings
should be reinforced with a minimum reinforcement of four No. 4 rebars, two top and two
bottom, perfect of width and deptii. Isolated-spread footings shall have a minimum base
dimension no less than 24 inches. Where the foundation is within 3 feet (horizontally) of
adjacent drainage swales, the adjacent footing should be embedded a minimum depth of
12 inches below the swale flow line. Conventional foundations provide a less rigid slab
system to reduce the potential for minor slab cracking.
All floor slabs should have a minimum thickness of 4 inches. Minimum reinforcement
should consist of No. 3 rebars at 18 inches on center (each way) or No. 4 rebars at 24
inches on center (each way). We emphasize tiiat it is the responsibility of tiie conti-actor
to ensure that the slab reinforcement is placed at slab mid-height. Slabs should be
underiain by a 2-inch layer of clean sand (sand equivalent greater than 30) to aid in
concrete curing, which is underiain by a 10-mil (or heavier) moisture bamer, which is in tum
underiain by 2 inches of clean sand to act as a capillary break. All penetrations through tiie
moisture barrier and laps should be sealed. The subgrade soil should be presoaked in
accordance with the recommendations of Section 6.2.3.
^ AGRA
Mr. Michael Roletti
RESG, Inc.
Project No. 0-252-104400
August 24, 2000
Page (15)
Our experience indicates that use of reinforcement in slabs and foundations can generally
reduce the potential for drying and shrinkage cracking. However, some cracking should
be expected as the concrete cures. Minor cracking is considered nonnal; however, it is
often aggravated by a high water/cement ratio, high concrete temperature at Uie time of
placement, small nominal aggregate size, and rapid moisture loss due to hot, dry, and/or
windy weather conditions during placement and curing. Cracking due to temperature and
moisture fluctuations can also be expected. The use of low slump concrete (not exceeding
4 inches at the time of placement) can reduce Uie potential for shrinkage cracking.
Moisture bamers can retard, but not eliminate vapor movement from tiie underiying soils
up through the slab. We recommend that the floor-covering contractor test Uie moisture
vapor flux rate prior to attempting application of moisture-sensitive flooring. "Breathable"
floor covering or special slab sealants should be considered if the vapor flux rates are high.
Floor covering manufacturers should be consulted for specific recommendations.
To reduce the potential for future cosmetic distress due to concrete shrinkage cracks and
minor soil movement, AGRA recommends that any proposed inflexible floor coverings,
such as ceramic tile or decorative stone, be installed on a 1 Vi-inch Uiick, wire-reinforced
mortar bed over a cleavage membrane, as recommended by the Ceramic Tile Institute.
The purpose of the mortar bed and cleavage membrane is to allow minor slab movement
under an inflexible floor covering without significant impact to Uie covering. Altemate
means of providing the same level of protection may also be considered if recommended
by a qualified tile contractor. Flexible joint material should be used where crack-sensitive
flooring overiies concrete joints
6.2.3 Moisture Conditioning
The slab subgrade soils underiying the post-tensioned foundation systems should be
presoaked in accordance with the recommendations presented in Table 4 prior to
placement of the moisture barrier and slab concrete. Lime-treatment should be performed
below conventional foundations. The subgrade soil moisture content should be checked
by a representative of the geotechnical consultant prior to slab constmction.
TABLE4
Minimum Presaturation Recommendations for F
Expansion Potential
(UBC 18-1-6)
Presoaking Recommendations
Very Low to Low (or Lime-Treated) Near-optimum moisture content to a depth of 6 inches
Medium Minimum of 1.3 times the optimum moisture content to a
minimum depth of 18 inches below slab subgrade
^ AGRA
® ?i#CVC^»C/ ^JCt*r
Mr. Michael Roletti
RESG, Inc.
Project No. 0-252-104400
August 24, 2000
Page (16)
Presoaking or moisture conditioning may be achieved in a number of ways. Based on our
professional experience, we have found tiiat minimizing the moisture loss on pads that
have been completed (by periodic wetting to keep the upper portion ofthe pad from drying
out) and/or berming the lot and flooding for a short period of time (days to a few weeks)
are some of the more efficient ways to meet the presoaking recommendations. If flooding
is performed, a couple of days to let the upper portion of the pad dry out and form a cmst
so equipment can be utilized should be anticipated.
6.3 SETTLEMENT
The recommended allowable bearing capadty is generally based on a total static settiement of
3/4 inche. Differential settiement is likely to be approximately one-half of the total settlement
shortly after application of tiie building load.
6.4 LATERAL EARTH PRESSURES AND RETAINING WALL DESIGN CONSIDERATIONS
The recommended lateral pressures forthe site soil (expansion index less than 90 per UBC Table
18-I-B) or either granular on site soils or import soils (expansion index less than 30) for level
backfill conditions are presented in Table 5.
TABLES
Lateral Earth Pressures
Conditions
Equivalent Fluid Weight (pcf)
Conditions Expansive Onsite Soils (El <90) Import Soils or Granular Onsite Soils (EI<30)
Active 45 35
At-Rest 70 55
Passive 325 325
Embedded stmctural walls should be designed for lateral earth pressures exerted on them. The
magnitude of these pressures depends on the amount of defonnation that the wall can yield under
load. If the wall can yield enough to mobilize the full shear strength of the soil, it can be designed
for "active" pressure. If the wall cannot yield under the applied load, the shear strength of the soil
cannot be mobilized and the earth pressure will be higher. Such walls should be designed for "at-
resf conditions. If a stmcture moves toward the soils, the resulting resistance developed by the
soil is the "passive" resistance.
For design purposes, the recommended equivalent fluid pressure for each case for walls founded
above the static ground water and backfilled with import soils of very low to low expansion
potential or onsite (moderately expansive soils) is provided in Table 5. The equivalent fluid
pressure values assume free-draining conditions. If conditions other than those assumed above
^ AGRA
Mr. Michael Roletti
RESG, Inc. August 24, 2000
Project No. 0-252-104400 Page (17)
are antidpated, Uie equivalent fluid pressure values should be provided on an individual-case
basis by tiie geotechnical engineer. Surcharge loading effects from Uie adjacent stmctures should
be evaluated by the geotechnical engineer. All retaining wall stiuctures should be provided with
appropriate drainage and appropriately waterproofed. The outiet pipe should be sloped to drain
to a suitable outiet. Typical wall drainage design is illusti'ated in Appendix C.
For sliding resistance, tiie friction coefficient of 0.35 may be used at the concrete and soil
interface. In combining the total lateral resistance, tiie passive pressure or the frictional resistance
should be reduced by 50 percent. Wall footings should be designed in accordance with stmctural
considerations. The passive resistance value may be increased by one-third when considering
loads of short duration such as wind or seismic loads.
The backfill soils should be compacted to at least 90 percent relative compaction (based on ASTM
Test Method D 1557). The walls should be constmcted and backfilled as soon as possible after
back-cut excavation. Prolonged exposure of back-cut slopes may result in some localized slope
instability.
Foundations for retaining walls in competent formational soils or properiy compacted fill should
be embedded at least 18 inches below lowest adjacent grade. At this depth, an allowable bearing
capacity of 2,000 psf may be assumed.
6.5 PRELIMINARY PAVEMENT DESIGN
For preliminary design purposes, we have utilized a design R-value of 12 for tiie pavement
subgrade soils based on our laboratory test results. It is recommended that representative
samples of actual subgrade materials be obtained after grading and tested to provide the final
pavement design. The project architect should review the provided traffic index indices prior to
final design.
Utilizing the design procedures outiined in the cunent Caltrans Highway Design Manual and a
design R-value of 12, we provide the following preliminary pavement sections for planning
purposes. We are presenting the preliminary pavement sections based on 2 traffic indices. The
project civil engineer/architect should detennine the appropriate traffic index.
• Traffic Index = 4.5 (20 vear desiqn life)
3.0 inches of asphalt concrete over 7.0 inches of Caltrans Class 2 aggregate base
• Traffic Index = 5.0 (20 vear desiqn life)
3.0 inches of asphalt concrete over 8.5 inches of Caltrans Class 2 aggregate base, or
3.5 inches of asphalt concrete over 7.5 inches of Caltrans Class 2 aggregate base, or
4.0 inches of asphalt concrete over 6.5 inches of Caltrans Class 2 aggregate base
^ AGRA
®
Mr. Michael Roletti
RESG, Inc. August 24, 2000
Project No. 0-252-104400 Page (18)
A traffic index of 4.5 is typically used for paridng areas for passenger vehicles witti an average
daily traffic index of less than 200 vehicles. A tiaffic index of 5.0 is similar to a cut-de-sac or local
street with an average daily traffic of less Uian 1,200 passenger vehicles with minor tiuck traffic.
For pavement areas subject to trash tmck or otiier heavy loading a Portland Cement Concrete
(PCC) pavement is recommended. We recommend a minimum of 6 inches of PCC on native
soils. The PCC pavement should be provided with appropriate steel reinforcement and crack-
control joints as designed by Uie project stmctural engineer. Minmum reinforcement should
consist of No. 3 rebars at 18 inches (on center) at slab midheight which continues through all
crack-conti"ol joints but not tiirough expansion joints. If saw-cuts are used, they should be a
minimum depth of 1/4 of the slab thickness and made witiiin 24 hours of concrete placement. We
recommend that sections be as neariy square as possible. A 3,250 psi concrete mix should be
utilized.
Asphalt Concrete (AC) and Class 2 base materials should conform to and be placed in accordance
with tiie latest revision of the Califomia Department of Transportation Standard Specifications
(Caltrans).
The pavement subgrade should be firm and unyielding when the pavement section is placed. The
upper 12 inches of subgrade soils should be moisture conditioned and compacted to at least 95
percent relative compaction based on ASTM Test Metiiod D1557 priorto placement of aggregate
base. The base layer should be compacted to at least 95 percent relative compaction as
detemiined by ASTM Test Method D1557. Untreated Class 2 aggregate base (not processed
miscellaneous base) should meet the four criteria of Section 26-1.02A of the most recent Caltrans
specifications.
We recommend that the curbs, gutters, and sidewalks be designed by the civil engineer or
stmctural engineer. Curias adjacent to paved areas should have bases in the subgrade material,
not the aggregate base course, to provide a cut-off to reduce water migration into the subgrade
soils. We suggest control joints, at appropriate inten/als. as determined by tiie civil or stmcture
engineer, be considered. We also suggest welded-wire mesh reinforcement and a minimum
thickness of 4 inches for sidewalk slabs.
We recommend steps be taken to prevent tiie subgrade soils from becoming saturated. Paved
areas should be properiy sloped so that water does not pond and infiltrate into the pavement
subgrade. Concrete swales should be designed in roadway or parking areas subject to
concentrated surface mnoff.
^ AGRA
Mr. Michael Roletti
RESG. Inc. August 24. 2000
Project No. 0-252-104400 Page (19)
6.6 CONTROL OF SURFACE WATER AND DRAINAGE CONTROL
Positive drainage of surface water away from stmctures is very important. No water should be
allowed to pond adjacent to buildings. Positive drainage may be accomplished by providing
drainage away from buildings at a gradient of at least 2 percent for a distance of at least 5 feet,
and further maintained by a swale or drainage path at a gradient of at least 1 percent Where
limited by 5-foot side yards, drainage should be directed away from foundations for a minimum
of 3 feet and into a collective swale or pipe system. Where necessary, drainage paths may be
shortened by use of area drains and collector pipes. Eave gutters are recommended to reduce
water filti-ation into the subgrade soils. Landscaping should be of a drought-tolerant variety and
use drip irrigation systems or other methods to reduce water infiltration in the subsurface per the
landscape architect.
6.7 SOIL CORROSIVITY
In general soil environments that are detrimental to concrete have high concentrations of soluble
sulfates and/or pH values of less than 5.5. Table 19-A-4 of UBC, 1997 provides specific guidelines
for the concrete mix-design when the soluble sulfate content of the soil exceeds 0.1 percent by
weight or 1000 ppm. The minimum amount of chloride ions in the soil environment that are
corrosive to steel, either in the form of reinforcement protected by concrete cover, or plain steel
substmctures such as steel pipes or piles is 500 ppm per Califomia Test 532. The results of our
laboratory tests on representative soils from the site indicated a soluble sulfate content of 0.024
percent suggests that the concrete should be designed in accordance with tiie Negligible Category
OfTable 19-A-4 of UBC, 1997. The test result also indicates a chloride content of barely less than
500 ppm, and a minimum resistivity of 935 ohm-cm, which indicates that the soil is severely
corrosive with respect to ferrous metals. The test results are provided in Appendix B.
Based on Uie results of the minimum resistivity testing, it is recommended that reinforcing bars
within concrete which is in contact with the soil be covered by 3 or more inches of concrete. It is
also recommended that buried metal pipes not be used or should be provided with some form of
corrosion protection such as epoxy coating or cathodic protection. Although tiie sulfate content
results indicate a negligible sulfate exposure, AGRA also recommends the use of Type II modified
Portland cement.
The above provides general guidelines for the on-site soils. Forthe appropriate evaluation and
mitigation design for the proposed stmctures and other substances with potential influence from
corrosive soils, a con-osion engineer may be consulted. These other substances include, but are
not necessarily limited to. buried copper tubing, aluminum elements in close vicinity of soils, or
stucco finish that can be potentially influenced.
^ AGRA
®
Mr. Michael Roletti
RESG, Inc. August 24. 2000
Project No. 0-252-104400 Page (20)
6.8 FLATWORK RECOMMENDATIONS
Since tiie site is underiain by expansive soils, differential heave ofthe site flatwork will likely occur
over the life of tiie project This heave can be reduced by using a 4-inch (minimum) thickness for
all flatworic and one of Uie following methods:
• Flatwork should be underiain by a minimum of 4 inches of Class 2 Base or pea gravel.
Flatwork should be reinforced with 6x6-6/6 welded wire mesh at slab midheight, or
• Flatwork should be underiain by native soils. Flatwork should be reinforced with No. 3
rebars at 18 inches on center (each way), at slab midheight
For both cases, slabs should have crack control joints at appropriate spacings and near all
comers. Slab subgrade should be presoaked in accordance with tiie recommendations in Section
6.2.3.
7.0 CONSTRUCTION OBSERVATION, UMITATIONS, AND PLAN REVIEW
The condusions and recommendations in this report are based in part upon data that were
obtained from a limited number of observations, site visits, excavations, samples, and tests which
were deemed representative of the site conditions at the time of tiie subsurface investigation. The
nature of many sites is such that differing geotechnical or geological conditions can occur within
small distances and under varying climatic conditions. Changes in subsurface conditions can and
do occur over time. Therefore, the findings, conclusions, and recommendations presented in this
report can be relied upon only if AGRA has the opportunity to observe the subsurface conditions
during grading and constmction of the project, in order to confinn that our preliminary findings are
representative for the site. In addition, we recommend that this office have an opportunity to
review the final grading and foundation plans in order to provide additional site-specific
recommendations.
^ AGRA
Mr. Michael Roletti
RESG. Inc. August 24, 2000
Project No. 0-252-104400 Page (21)
8.0 REFERENCES
CDMG, 1996, Probabilistic Seismic Hazard Assessment for Uie State of Califomia, Open-File
Report No. 96-08.
Hart, 1994, Fault-Rupture Hazard Zones in Califomia, Alquist-Priolo Spedal study Zones Act of
1972 witii Index to Spedal Study Zones Maps: Department of Conservation, Division of
Mines and Geology. Spedal Publication 42.
Housner, G.W. 1970, Sti-ong Ground Motion, in Earthquake Engineering, Robert Wiegel (ed.). pp.
75-92.
Intemational Conference of Building Officials. 1997, Unifonn Building Code.
Ishihara, K., 1985. "Stability of Natural Deposits during Earthquakes", Proceedings ofthe Eleventh
Intemational Conference of Soil Mechanics and Foundation Engineering, A.A. Belkema
Publishers, Rotterdam, Netheriands.
Ken Stocton Architect, 2000, 24-Unit Housing Development 670 Laguna Drive, Carisbad, CA,
dated. Febmary 5, 2000, Sheets No. Al and A2
Marcuson, W.F., III, and W.A. Bieganousky, 1977, "SPT and Relative Density in Coarse Sands".
Joumal of ttie Geotechnical Engineering Division. ASCE 103 (FT11): 1295-1309.
National Research Coundl, 1985, "Liquefaction of Soils During Earthquakes" Report No.: CETS-
EE-001, National Academy Press, Washington, D.C.
Schnabel, P.B., and Seed, H.B., 1973. Accelerations in Rock for Earthquake in the Westem
United States. Seismological Society of America Bulletin, Vol. 63, No. 2, pp. 501-575.
Seed, H.B., and Idriss. I.M.. 1971. "Simplified Procedure for Evaluating Soil Liquefaction
Potential". Joumal ofthe Soil mechanics and Foundation Division. ASCE 97 (SM9): 1249-
1273.
. 1982, "Ground Motions and Soil Liquefaction During Earttiquake". Monograph Series,
Earthquake Engineering Research Institute, Beri<eley, Califomia.
Seed, H.B., Idriss, I.M., and Kiefer. F.W., 1969, Characteristics of Rock Motions During
Earthquakes, JSMFD, ASCE, WE95, No. SMS, pp. 1199-1218.
^ AGRA
Mr. Michael Roletti
RESG, Inc. August 24. 2000
Project No. 0-252-104400 Page (22)
Seed, H.B., Murari<la, R., Lysmer, J.. and Idriss, I., 1975, "Relationships Between Maximum
Acceleration, Maximum Veiodty, Distance from Source and Local Site Conditions for
Moderately Stiong Earthquake", Report No. EERC 75-17, University of Califomia,
Beri<eley.
, 1976, Relationships of Maximum Accelerations, Maximum Velocity, Distance from
Source and Local Site Conditions for Moderately Sti-ong Earthquakes, Bull. Seism, Soc.
Amer., 66:4, dated August
Tan, S. S., and Kennedy, M. P., 1996, Geologic Maps of the Northwestem Part of San Diego
County, Califomia, Plate I, Geologic Map of Oceanside, San Luis Rey, and San Marcos
7.5' Quadrangles, San Diego County Califomia, map scale 1:24,000.
Mualchin, L., 1996, Califomia Seismic Hazard Map: State of Califomia Department of
Transportation, map scale 1:1,500,000.
Uniform Building Code, 1997, Intemational Conference of Building Officials, Vol. 2, with Maps of
Known Active Fault Near-Source Zones in Califomia and Adjacent Portions of Nevada,
map scale 1:156,000.
United States Department of Agriculture, Aerial Photograph, Flight No. AXN-14, Frame No. 19,
dated 5/2/53.
^ AGRA
APPENDIX A
.4
RESG, Inc. Job. No. 0-252-104400
09/03/2000
Page A-1
UNIFIED SOIL CLASSIFICATION
Pt OL CL SC SM SP SW GC GM GP GW
Highly
Organic
Soils
Silts and Clays Liquid Limit >50%
Silts and Clays Liquid Limit <50%
Sands with Fines Clean Sands >12% Fines I <5% Fines Sravels with Fines Clean Gravels >12%Fines1 <.q% Finp^
Sands - more than 50% of coarse
fraction Is smaller than No. 4 sieve
Fine Grained Soils (more than 50% is smaller than No. 200 sieve)
Gravels - more than 50% of coarse
fraction is larger than No. 4 sieve
Coarse Grained Soils (more than 50% Is larger than No. 200 sieve)
X Ul Q
o
I-
a.
/ /
/ M /
/
/
•/^
r
/
M lor 3H
L-M f
LOI OL
LABORATORY CLASSIFlCAnON CRITERIA
GW and SW: Cu = D«, /D,, greater than 4 for GW, greater than 6 for SW
Cc = DJO^/DM X D,o between 1 and 3
GP and SP: Clean gravel or sand not meeting requirements for GW and SW
GM and SM: Atterberg Limits below "A" LINE and PI less than 4
GC and SC: Atterberg Limits above "A" LINE and Pl greater than 7
Silt or Clay Fine Sand Medium Sand Coarse Sand Fine Gravel Coarse Gravel Cobble Boulder
Sieve 2C
Size
10 40 10 4 3/4" 3 12"
20 40 SO ao
UQUID UMIT
Classification of earth matenals Is based on field inspection and should not be construed to imply laboratory analysis unless so stated
m
MATERIAL
Asphalt
Concrete
Conglomerate
Sandstone
silty Sandstone
Clayey Sandstone
SYMBOLS
Calcaerous Sandstone
-c:-:: Mad
I r
/ / / / / /
Limestone
Dolostone
A A
A A Breccia
4 4^
Siltstone
Volcanic Ash/Tuff
Metamorphic Rock
Sandy Siltstone
Clayey Siltstone /Silty Claystone
Claystone/Shale
f i\ Quartzite
V—V
'\/^\/\ Extrusive Igneous Roc^
+ + Intrusive Igneous Rock
CONSISTENCY CLASSIFICATION FOR
SOILS
AcconJinq to the Standard Penetration Test
Blows / Foot' Granular Blows / Foot* Cohesive
0-5 Very Loose 0-2 Very Soft
6-10 Loose 2-4 Soft
11-30 \/Iedium Dense 4-a Medium Stiff
31 -50 Dense 8 - 15 Stiff
50 Very Dense 15-30 Very Stiff
>30 Hard
' using 140-lb. hammer with 30" drop = 350 ft-lb/blow
LEGEND OF BORING
Bulk Sample I —
Driven Sample
Water Level 2
Unit Change
_ Unconfomiitv .
Material_£;han3S. _
Bottom of the Boring
"NSR" indicates NO SAMPLE RECOVERY
^ AGRA
RESG. Inc. Job. No. 0-252-104400
09/03/2000
Page A-2
TEST BORING LOG BORING: B-1 Sheet 1 of 1
Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21
Hole Diameter (In): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor C & K Drilling
Depth to Groundwater (ft): 16 Borinp Completion: Backfilled w/cuttings on Caving: None observed
116 14.5
122 12.3
17
36
45
1.4" 1
Bulk 2
2.5"
1.4"
-62 2.5"
20
SM
CL
FILL
Brown, damp, loose SILTY SAND.
COLLUVIUM:
Brown, moist, very stiff SANDY CLAY Interiayered with
medium dense CLAYEY SAND.
TERRACE DEPOSITS:
Presence of gravel and cobbles indicates terrace
deposits as encountered in near-by borings.
SANTIAGO FORMATION:
White to light yellow-brown, moist CLAYEY
SANDSTONE, weakly to moderately cemented.
.saturated.
25
NOTES:
1. Approximate surface elevation obtained from USGS
7.5' Topographic Series, Encinitas Quadrangle, map
scale 1:24000.
2. Sampler driven by 140-lb hammer falling from 30"
height.
Q.
CO U
0.9-
1142.
Ul
= cr
Q Q.
a
as
O o
Su
o a. >• 1-
_a> a.
E
(0
to
THIS BORING LOG SUMMARY APPLIES ONLY AT
THE TIME AND LOCATION INDICATED.
SUBSURFACE CONDITiONS MAY DIFFER AT
OTHER LOCATIONS AND TIMES.
3 O Logged by: TMM
^ AGRA
RESG, Inc. Job. No. 0-252-104400
09/03/2000
Page A-3
TEST BORING LOG BORING: B-2 Sheet 1 of 1
Date(3) Drilled: 3/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21
Hole Diameter (In): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor C & K Drilling
Depth to Groundwater (ft): 15 Boring Complotlon: Backfilled w/cuttings onS/aO^aving: None observed
117
113
11.1
16.9
21
40
70
-84
Bulk
1.4"
2.5"
1.4"
2.5"
10 -J
7l5
20
,1,
SM
CL
SC
FILL
Brown, damp, loose SILTY SAND.
COLLUVIUM:
Brown, moist, medium stiff SANDY CLAY.
TERRACE DEPOSITS:
Greenish brown, moist, medium dense CLJAYEY SAND;
white and orange streaks; scattered gravel.
...Increased gravel.
SANTIAGO FORMATION:
White to light yellow-brown, wet CLAYEY
SANDSTONE, weakly to moderately cemented.
...saturated.
25
NOTES:
1. Approximate surface elevation obtained from USGS
7.5' Topographic Series, Encinitas Quadrangle, map
scale 1:24000.
2. Sampler driven by 140-lb hammer falling from 30"
height.
01
0)
a £ w —. *• in « c c o IU .s •.
CO o
O.S-z 5
Q «
tu ^
in
O o
Su
3 o
O ST U w
il
a. >. I-
CL
E rs CO
o z a
a. E
CO
ll
.= 2
a. dj
ti <u
Q Si
c _ o
CO 3 •oE
<a (A
S in C JS 3 U
THIS BORING LOG SUMMARY APPLIES ONLY AT
THE TIME AND LOCATION INDICATED.
SUBSURFACE CONDITIONS MAY DIFFER AT
OTHER LOCATIONS AND TIMES.
Logged by: TMM
^ AGRA
®
RESG. Inc. Job. No. 0-252-104400
09/03/2000
Page A-4
TEST BORING LOG BORING: B-3 Sheet 1 of 1
Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21.5
Hole Diameter (In): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor C & K Drilling
Depth to Groundwater (ft): 18 Boring Completion: Backfilled w/cuttings on Caving: None observed
107
120
17.9
14.2
10
30
-62
62
2.5"
1.4"
2.5"
1.4"
10
SM
CL
15
•1]
U.
20
1
FILL
Brown, damp, loose SILTY SAND.
COLLUVIUM:
Brown, moist, medium stiff SANDY CLAY.
TERRACE DEPOSITS:
Greenish brown, moist, medium dense SILTY SAND;
scattered gravel.
SANTIAGO FORMATION:
White to light yellow-brown, moist CLAYEY
SANDSTONE, weakly to moderately cemented.
..saturated.
25
NOTES:
1. Approximate surface elevation obtained from USGS
7.5' Topographic Series, Encinitas Quadrangle, map
scale 1:24000.
2. Sampler driven by 140-lb hammer falling from 30"
height.
CO 6
Ul "St
oc O.S-w z 5
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THIS BORING LOG SUMMARY APPLIES ONLY AT
THE TIME AND LOCATION INDICATED.
SUBSURFACE CONDITIONS MAY DIFFER AT
OTHER LOCATIONS AND TIMES.
Logged by: TMM
^ AGRA
®
RESG, Inc. Job. No. 0-252-104400
09/03/2000
Page A-5
TEST BORING LOG BORING: B-4 Sheet 1 of
Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21.5
Hole Diameter (in): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor C & K Drilling
Depth to Groundwater (ft): 18 Boring Complotlon: Backfilled w/cuttings on Caving: None observed
106 17.1
122
36
13.2 42
68
Bulk I 1
2.5"
1.4"
2.5"
1.4"
10
15
20
SM
i I
CL
GC
FILL
Brown, damp, loose SILTY SAND.
COLLUVIUM:
Brown, moist, medium stiff SANDY CLAY.
TERRACE DEPOSITS:
Presence of gravel and cobbles, up to 6" diameter,
indicates terrace deposits as encountered in near-by
borings.
SANTIAGO FORMATION:
White to light yellow-brown, moist CLAYEY
SANDSTONE, weakly fo moderately cemented.
...saturated.
25
NOTES:
1. Approximate surface elevation obtained from USGS
7.5' Topographic Series, Encinitas Quadrangle, map
scale 1:24000.
2. Sampler driven by 140-lb hammer falling from 30"
height.
01
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01
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•a £
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= M CiS 3 U
THIS BORING LOG SUMMARY APPLIES ONLY AT
THE TIME AND LOCATION INDICATED.
SUBSURFACE CONDITIONS MAY DIFFER AT
OTHER LOCATIONS AND TIMES.
Logged by: TMM
^ AGRA
®
RESG, Inc. Job. No. 0-252-104400
09/03/2000
Page A-6
TEST BORING LOG BORING: B-5 Sheet 1 of 1
Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21
Hole Diameter (in): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor C & K Drilling
Depth to Groundwater (ft): 18.5 fJg/^^^°'"P^'*^°"' Backfilled w/cuttings on Caving: None obsen/ed
123 12
121 14
12
-68
48
1.4"
2.5"
-98
1.4"
Bulk
2.5"
10
1 1
I-
CL
GC
SC""
15
\
20
COLLUVIUM:
Brown, moist, stiff SANDY CLAY; minute voids.
TERRACE DEPOSITS:
Greenish brown, moist, medium dense CL7VYEY
\ scattered cobbles.
Greenish brown, moist, medium dense CLAYEY SAND;
sc:attered gravel and cobbles.
SANTIAGO FORMATION:
White to light yellow-brown, moist CLAYEY
SANDSTONE, weakly to moderately cemented.
...saturated.
25
NOTES:
1. Approximate surface elevation obtained from USGS
7.5' Topographic Series, Encinitas Quadrangle, map
scale 1:24000.
2. Sampler driven by 140-lb hammer falling from 30"
height.
o>
01
E~
0 c
c o
01 .S 0.
CO u uj-3
0.5-z 5
Q " _J it.
ai ^
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in I" a a.
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=
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il
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ra
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.= 2
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3 U
THIS BORING LOG SUMMARY APPLIES ONLY AT
THE TIME AND LOCATION INDICATED.
SUBSURFACE CONDITIONS MAY DIFFER AT
OTHER LOCATIONS AND TIMES.
Logged by: TMM
^ AGRA
®
m
APPENDIX B
Mr. Tim Carroll
O'Day Consultants
Project No. 0-252-103800
July 21, 2000
Page (B-1)
APPENDIX B
Laboratory Testing Procedures and Test Results
Expansion Index Tests: The expansion potential of selected materials was evaluated by the
Expansion Index Test, U.B.C. Standard No. 18-2. Specimens are molded under a given
compactive energy to approximately the optimum moisture content and approximately 50 percent
saturation or approximately 90 percent relative compaction. The prepared 1-inch thick by 4-inch
diameter specimens are loaded to an equivalent 144 psf surcharge and are inundated with tap
water until volumetric equilibrium is reached. The results of these tests are presented in the table
below:
Sample
Location Sample Description
Compacted
Dry Density
(pcf)
Expansion
Index
Expansion
Potential
B-1 @ 6' Brown clayey sand 94.0 108 High
B-3 @ 0'-4' Brown silty sand 115.6 0 Very Low
Consolidation/Collapse Testinq: Selected samples were loaded in a consolidometer to the
proposed overiDurden pressure. The samples were then inundated with water and the percent
hydrocollapse was measured and recorded below. A negative value indicates swell.
Sample Location % Hydrocollapse
B-3, 5' -0.83 @ 1000 psf (expansion)
Classification or Grain Size Tests: Typical materials were subjected to mechanical grain-size
analysis by sieving from U.S. Standard brass screens (ASTM Test Method D422). Hydrometer
analyses were performed where appreciable quantities of fines were encountered. The data was
evaluated in detennining the classification of the materials. The grain-size distribution curves are
presented in the test data and the Unified Soil Classification (USCS) is presented in both the test
data and the logs. Below is a summary of the percent passing the No. 200 Sieve.
^ AGRA
Mr. Tim Carroll
O'Day Consultants
Project No. 0-252-103800
July 21, 2000
Page (B-2)
Sample Location Percent Passing No. 200 Sieve
B-1, 5'-7' 64
B-2, 2'-5' 50
Chloride Testinq: Representative soil samples were obtained for testing for chloride content in
accordance with Califomia Test Method 422. The results are presented in the following table.
Sample Location Chloride Content, ppm Chloride Attack Potential*
B-2, 2'-5' 490 Moderate
'Per Cal Test MethcxJ 532 and City of San Oiego Program Design Guidelines for Consultants. 1992.
Minimum Resistivity and pH Tests: Minimum resistivity and pH tests were performed in general
accordance with Califomia Test Method 643. The results are presented in the table below:
Sample Location pH Minimum Resistivity (ohms-cm) Corrosion Potential*
B-2, 2'-5' 8.0 937 Very High
' per City of San Diego Program Design Guidelines for Consultants, 1992.
"R"-Value: The resistance "R"-value was detennined by the Califomia Materials Method No. 301
for base, subbase, and basement soils. The samples were prepared and exudation pressure and
"R"-value determined. The graphically detennined "R"-value at exudation pressure of 300 psi is
reported.
Sample Number R-Value
B-1, 5'-7' 12
^ AGRA
®
Mr. Tim Carroll
O'Day Consultants
Project No. 0-252-103800
July 21, 2000
Page (B-3)
Moisture and Densitv Determination Tests: Moisture content and dry density determinations
were perfonned on relatively undisturbed samples obtained from the test borings. The results of
these tests are presented in the boring logs. Where applicable, only moisture content was
detennined from "undisturtsed" or disturtsed samples.
Soluble Sulfates: The soluble sulfate contents of selected samples were detennined by
standard geochemical methods. The test results are presented in the table below:
Sample Location Soluble Sulfate Content (%) Sulfate Exposure*
B-2. 2'-5' 0.024 Negligible
• Based on the 1997 edition of the Uniform Building Code, Table No. 19-A^, prepared by the Intemational Conference of Building
Officials (ICBO, 1997).
Direct Shear Tests: Direct shear tests were performed on selected remolded and/or undisturbed
samples which were soaked for a minimum of 24 hours under a surcharge equal to the applied
normal force during testing. After transfer of the sample to the shear box, and reloading the
sample, pore pressures set up in the sample due to the transfer were allowed to dissipate for a
period of approximately 1 hour prior to application of shearing force. The samples were tested
under various nonnal loads, a motor-driven, strain-controlled, direct-shear testing apparatus at a
strain rate of 0.0025 inches per minute. The test results are presented in the test data.
Sample Location Sample Description Friction Angle
(degrees)
Apparent Cohesion
(psf)
B-3, 5'-6' Sandy Clay 25 300
^ AGRA
®
APPENDIX C
^1
•13&
GENERAL EARTHWORK AND GRADING SPECIFICATIONS FOR ROUGH GRADING
1.0 General
1.1 Intent: These General Earthwori< and Grading Specifications are for the grading
and earthwork shown on the approved grading plan(s) and/or indicated in the
geotechnical report(s). These Specifications are a part of the recommendations
contained in the geotechnical report(s). In case of conflict, the specific
recommendations in the geotechnical report shall supersede these more general
Specifications. Observations of the earthwori< by the project Geotechnical
Consultant during the course of grading may result in new or revised
recommendations that could supersede these specifications or the
recommendations in the geotechnical report(s).
1.2 The Geotechnical Consultant of Record: Prior to commencement of work, the
owner shall employ the Geotechnical Consultant of Record (Geotechnical
Consultant). The Geotechnical Consultants shall be responsible for reviewing the
approved geotechnical report(s) and accepting the adequacy of the preliminary
geotechnical findings, conclusions, and recommendations prior to the
commencement ofthe grading.
Prior to commencement of grading, the Geotechnical Consultant shall review the
"work plan" prepared by the Earthwork Contractor (Contractor) and schedule
sufficient personnel to perform the appropriate level of obsen/ation, mapping, and
compaction testing.
During the grading and earthwork operations, the Geotechnical Consultant shall
observe, map, and document the subsurface exposures to verify the geotechnical
design assumptions. If the obsen/ed conditions are found to be significantly
different than the interpreted assumptions during the design phase, the
Geotechnical Consultant shall inform the owner, recommend appropriate changes
in design to accommodate the obsen/ed conditions, and notify the review agency
where required. Subsurface areas to be geotechnically obsen/ed, mapped,
elevations recorded, and/or tested include natural ground after it has been cleared
for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all
key bottoms, and benches made on sloping ground to receive fiil.
^ AGRA
•^ecvC'AJ Piper
The Geotechnical Consultant shall obsen/e the moisture-conditioning and
processing of the subgrade and fill materials and perform relative compaction
testing of fill to detennine the attained level of compaction. The Geotechnical
Consultant shall provide the test results to the owner and the Contractor on a
routine and frequent basis.
1.3 The Earthwork Contractor The Earthwori< Contractor (Contractor) shall be
qualified, experienced, and knowledgeable in earthwork logistics, preparation and
processing of ground to receive fill, moisture-conditioning and processing of fill, and
compacting fill. The Contractor shall review and accept the plans, geotechnical
report(s), and these Specifications prior to commencement of grading. The
Contractor shall be solely responsible for performing the grading in accordance with
the plans and specifications. The Conti-actor shall prepare and submit to the owner
and the Geotechnical Consultant a work plan that indicates the sequence of
earthwork grading, the number of "spreads" of wori< and the estimated quantities
of daily earthwork contemplated forthe site priorto commencement of grading. The
Contractor shall inform the owner and the Geotechnical Consultant of changes in
work schedules and updates to the wori< plan at least 24 hours in advance of such
changes so that appropriate observations and tests can be planned and
accomplished. The Contractor shall not assume that the Geotechnical Consultant
is aware of all grading operations.
The Contractor shall have the sole responsibility to provide adequate equipment
and methods to accomplish the earthwori< in accordance with the applicable grading
codes and agency ordinances, these Specifications, and the recommendations in
the approved geotechnical report(s) and grading plan(s). If, in the opinion of the
Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil,
improper moisture condition, inadequate compaction, insufficient buttress key size,
adverse weather, etc., are resulting in a quality of work less than required in these
specifications, the Geotechnical Consultant shall reject the work and may
recommend to the owner that construction be stopped until the conditions are
rectified.
2.0 Preparation of Areas to be Filled
2.1 Clearing and Grubbing: Vegetation, such as bmsh, grass, roots, and other
deleterious material shall be sufficientiy removed and properiy disposed of in a
method acceptable to the owner, goveming agencies, and the Geotechnical
Consultant.
^ AGRA
The Geotechnical Consultant shall evaluate the extent of these removals depending
on specific site conditions. Earth fill material shall not contain more than 1 percent
of organic materials (by volume). No fill lift shall contain more than 5 percent of
organic matter. Nesting ofthe organic materials shall not be allowed.
If potentially hazardous materials are encountered, the Conti-actor shall stop work
in the affected area, and a hazardous material specialist shall be infonned
immediately for proper evaluation and handling of these materials priorto continuing
to wori< in that area.
As presently defined by the State of Califomia, most refined petroleum products
(gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents
that are considered to be hazardous waste. As such, the indiscriminate dumping
or spillage of Uiese fluids onto the ground may constitute a misdemeanor,
punishable by fines and/or imprisonment, and shall not be allowed.
2.2 Processinq: Existing ground that has been declared satisfactory for support of fill
by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches.
Existing ground that is not satisfactory shall be overexcavated as specified in the
following section. Scarification shall continue until soils are broken down and free
of large clay lumps or clods and the working surface is reasonably uniform, fiat, and
free of uneven features that would inhibit unifomn compaction.
2.3 Overexcavation: In addition to removals and overexcavations recommended in the
approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated,
spongy, organic-rich, highly fractured or othenA/ise unsuitable ground shall be
overexcavated to competent ground as evaluated by the Geotechnical Consultant
during grading.
2.4 Benching: Where fills are to be placed on ground with slopes steeper than 5:1
(horizontal to vertical units), the ground shall be stepped or benched. Please see
the Standard Details for a graphic illustration. The lowest bench or key shall be a
minimum of 15 feet wide and at least 2 feet deep, into competent material as
evaluated by the Geotechnical Consultant. Other benches shall be excavated a
minimum height of 4 feet into competent material or as otherwise recommended by
the Geotechnical Consultant. Fill placed on ground sloping flatterthan 5:1 shall also
be benched or othenwise overexcavated to provide a flat subgrade for the fill.
2.5 Evaluation/Acceptance of Fill Areas: All areas to receive fill, including removal and
processed areas, key bottoms, and benches, shall be observed, mapped, elevations
recorded, and/or tested priorto being accepted by the Geotechnical Consultant as
^ AGRA
®
suitable to receive fill. The Conti-actor shall obtain a written acceptance from the
Geotechnical Consultant prior to fill placement. A licensed surveyor shall provide
tine survey control for determining elevations of processed areas, keys, and
benches.
3.0 Fill Material
3.1 General: Material to be used as fill shall be essentially free of organic matter and
other deleterious substances evaluated and accepted by the Geotechnical
Consultant prior to placement. Soils of poor quality, such as those with
unacceptable gradation, high expansion potential, or low strength shall be placed
in areas acceptable to the Geotechnical Consultant or mixed with other soils to
achieve satisfactory fill material.
3.2 Oversize: Oversize material defined as rock, or other irreducible material with a
maximum dimension greater than 8 inches, shall not be buried or placed in fill
unless location, materials, and placement methods are specifically accepted by the
Geotechnical Consultant. Placement operations shall be such that nesting of
oversized material does not occur and such that oversize material is completely
surrounded by compacted or densified fill. Oversize material shall not be placed
within 10 vertical feet of finish grade or within 2 feet of future utilities or underground
construction.
3.3 Import: If importing of fill material is required for grading, proposed import material
shall meet the requirements of Section 3.1. The potential import source shail be
given to the Geotechnical Consultant at least 48 hours (2 working days) before
importing begins so that its suitability can be determined and appropriate tests
perfonned.
4.0 Fill Placement and Compaction
4.1 Fill Lavers: Approved fill material shall be placed in areas prepared to receive fill
(per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose
thickness. The Geotechnical Consultant may accept thicker layers if testing
indicates the grading procedures can adequately compact the thicker layers. Each
layer shall be spread evenly and mixed thoroughly to attain relative unifonnity of
material and moisture throughout.
^ AGRA
®
4.2 RII Moisture Conditioninq: Fill soils shall be watered, dried back, blended, and/or
mixed, as necessary to attain a relatively unifonn moisture content at or slightiy over
optimum. Maximum density and optimum soil moisture content tests shall be
performed in accordance with the American Society of Testing and Materials (ASTM
Test Method Dl 557-91).
4.3 Compaction of Fill: After each layer has been moisture-conditioned, mixed, and
evenly spread, it shall be unifonnly compacted to not less tiian 90 percent of
maximum dry density (ASTM Test Method Dl 557-91). Compaction equipment shall
be adequately sized and be either specifically designed for soil compaction or of
proven reliability to efficiently achieve the specified level of compaction with
unifonmity.
4 4 Compaction of Fill Slopes: In addition to nonnal compaction procedures specified
above, compaction of slopes shall be accomplished by backrolling of slopes with
sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods
producing satisfactory results acceptable to the Geotechnical Consultant. Upon
completion of grading, relative compaction of the fill, out to the slope face, shall be
at least 90 percent of maximum density per ASTM Test Method D1557-91.
4.5 Compaction Testinq: Field tests for moisture content and relative compaction ofthe
fiil soils shall be perfonned by the Geotechnical Consultant. Location and frequency
of tests shall be at the Consultant's discretion based on field conditions
encountered. Compaction test locations will not necessarily be selected on a
random basis. Test locations shall be selected to verify adequacy of compaction
levels in areas that are judged to be prone to inadequate compaction (such as close
to slope faces and at the fill/bedrock benches).
4.6 Frequency of Compaction Testing: Tests shall be taken at intervals not exceeding
2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment.
In addition, as a guideline, at least one test shall be taken on slope faces for each
5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The
Contractor shall assure that fill construction is such that the testing schedule can be
accomplished by the Geotechnical Consultant. The Contractor shall stop or slow
down the earthwork construction if these minimum standards are not met.
4.7 Compaction Test Locations: The Geotechnical Consultant shall document the
approximate elevation and horizontal coordinates of each test location. The
Contractor shall coordinate with the project sun/eyor to assure that sufficient grade
stakes are established so that the Geotechnical Consultant can detennine the test
locations with sufficient accuracy. At a minimum, two grade stakes within a
^ AGRA
®
horizontal distance of 100 feet and vertically less than 5 feet apart from potential
test locations shall be provided.
5.0 Subdrain Installation
Subdrain systems shall be installed in accordance with tiie approved geotechnical report(s),
the grading plan, and the Standard Details. The Geotechnical Consultant may recommend
additional subdrains and/or changes in subdrain extent, location, grade, or material
depending on conditions encountered during grading. All subdrains shall be surveyed by
a land surveyor/civil engineer for line and grade after installation and prior to burial.
Sufficient time should be allowed by the Contractor for these surveys.
6.0 Excavation
Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the
Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical
plans are estimates only. The actual extent of removal shall be detennined by the
Geotechnical Consultant based on the field evaluation of exposed conditions during
grading. Where fill-over-cut slopes are to be graded, the cut portion of tine slope shall be
made, evaluated, and accepted by the Geotechnical Consultant prior to placement of
materials for constnjction ofthe fill portion ofthe slope, unless othenwise recommended by
the Geotechnical Consultant.
7.0 Trench Backfills
7.1 The Contractor shall follow all OHSA and Cal/OSHA requirements for safety of
trench excavations.
7.2 All bedding and backfill of utility trenches shall be done in accordance with the
applicable provisions of Standard Specifications of Public Works Construction.
Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The
bedding shall be placed to 1 foot over the top ofthe conduit and densified by jetting.
Backfill shall be placed and densified to a minimum of 90 percent of maximum from
1 foot above the top of the conduit to the surface.
7.3 The jetting of the bedding around the conduits shall be obsen/ed by the
Geotechnical Consultant.
^ AGRA
®
7.4 The Geotechnical Consultant shall test tiie ti-ench backfill for relative compaction.
At least one test should be made for every 300 feet of ti-ench and 2 feet of fill.
7.5 Lift tiiickness of ti-ench backfill shall not exceed tiiose allowed in tiie Standard
Specifications of Public Works ConstiTJCtion unless tiie Conti^ctor can demonsti-ate
to the Geotechnical Consultant that Uie fill lift can be compacted to the minimum
relative compaction by his altemative equipment and method.
^ AGRA
rcoiiPACTEO^nr
PROJECTHD PLANE
1 TO 1 MAXB4UM FROM T0€
OF SLOPE TO APPHOVeS OnOUNO
NATURAL
GROUND
REMOVE
UNSUTTABLE
MATERIAL
FILL SLOPE
BENCH
HEK3HT
2* HIN.
KET DEPTH
L—15* UIN.
LOWEST BENCH
(KEY)
NATURAL
GROUND
•'TYPICAL
BENCH
HBGHT
FILL-OVER-CUT
SLOPE
REMOVE
UNSUITABLE
MATERIAL
— 2* MIN.
KET DEPTH
CUT FACE
SHALL BE CONSTRUCTH3 PnOfl
TO fXL PLACEMe«-TO ASSURE
A06QUAT1 OeXOOJC CONOmONS
CUTFACC
TO BE CONSTRUCTSa PRIOfl
TO FIL PtACSi4en-v
OVERBUILT ANO
TRIM BACK
OESIGN SLOPE
PROJECTED PUkNE
1 TO 1 MAXIMUM FROM
TOE OF SLOPE TO
APPROVED QROUNO
T MIN.
KEY DEPTH
2%X4IN->-
I LOWEST BENCH]
BENCH
R£M<r/E
NSUrrABLE
MATERIAL
CUT-OVER-FILL
SLOPE
For Subdrains See
Standard Detail O
4'TYPICAL
BENCH HaOHT
BaOBNQ 8HMX BE DONE WHEN SLOPES
ANGLE IS EQUAL TO OR GREATER THAN 5:1
MWWUM Be«H HEXSHT SHALL BE 4 FEET
MINIMUM FRi. WWTH SHALL BE 8 FEET
KEYING AND BENCHING GENERAL EAHTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS A
^ AGRA
FINISH GRADE
SLOPE
FACE
-10' MIN.:nr:^COMPACTED FlLL -j:zs::r.
^^^^^^
JETTED OR FLOODED
GRANULAR MATERIAL
• Oversiz9 rock Is larger ttian 8 inches
In largest dimensioa
• Excavata a trerx:h in the compacted
fill deep erxxigh to bury all ttie rock.
• Backfin with granular soil jetted or
flooded In placa to fill all the voids.
• Do not bury rock within 10 feet of
finish grade.
• Windnsw of buried rock shafl be
paraflei to the finished slope fifl. ELEVATION A-A'
PROFILE ALONG WINDROW
A
JETTED OR FLOODED
GRANULAR MATERIAL
OVERSIZE
ROCK DISPOSAL
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS B
^ AGRA
NATURAL
GROUND
BENCHING REMOVE
UNSUITABLE
MATERIAL
OVERLAP FROM THE TOP
RING TIED EVERY 6 FEET
CALTTUNS CLASS II \[
PERMEABLE OR #2 ROCK-^
(9FT.'/FT.) WRAPPED IN
FILTER FABRIC
RLTSR FABRIC
(MIRAF1140
APPROVED
EQUIVALENT)
CANYON SUBDRAIN OUTLET DETAIL
PERFORATED PIPE
6*<fr MIN.
V COLLECTOR'PIPE SHALL
BE MINIMUM 6* DIAMETER
SCHEDULE 40 PVC PERFORATED
PIPE. SEE STANDARD DETAIL D
FOR PIPE SPECIFICATION
DESIGN
RNISHED
GRADE
.NON-PERFORATED
6'^ MIN.
FILTER FABRIC
(MIRAFI 140 OR
APPROVED
EQUIVALENT)
#2 ROCK WRAPPED IN FILTER
FABRIC OR CALTRANS CUVSS II
PERMEABLE.
CANYON SUBDRAINS
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS C
^ AGRA
IS' MIN.
OUTLET PIPES
4'^ NON-PERFORATED PIPE,
100' MAX O.C. HORIZONTALLY,
30' MAX. O.C. VERTICALLY BACKCUT1:1
OR FU^TTHR
KEY r
DEPTH I
2* MIN. 15' MIN.
KEY WIDTH POSmVE SEAL
SHOULD BE
PROVIDED AT
THE JOI
OUTLET PIPE
(NON-PERFORATED)
CALTRANS CLASS II
PERMEABLE OR #2 ROCK
(3FT.'/FT.) WRAPPED IN
FILTER FABRIC
12* MIN. OVERLAP FROM THE TOP
HOG RING TIED EVERY 6 FEET
\
FILTER FABRIC
(MIRAFI 140 OR
APPROVED
EQUIVALENT)
/
T-CONNECnON.FOR
COLLECTOR PIPE TO
OUTLET PIPE
SUBDRAIN INSTALLATION - Subdrain collector pipe shafl be Instafled witii perforatkjns down or,
untess ottierwisa designated by ttie geotechnical consultant. Outiet pipes shafl be non-perforated
pipe. The sutxlrain pipe shaJI have at least 8 perforatkxTS uniformly spaced per foot Perforation shafl
be Vi' to Vi" ff dnHed holes are used. Afl subdrain pipes shall have a gradient at least 2% towards the
outiet
SUBDRAIN PIPE - Subdrain pipe stiaJI be ASTM D2751, SDR 23.5 or ASTM D1527, Schedule 40. or
ASTM D3034, SDR 23.5, Schedule 40 Polyvinyl Chloffcle Plastic (PVC) pipe.
Afl outiet pipe stiall be placed in a trench no wider tiian twice the subdrain pipe. Pipe shafl be in soil
of SE^SO jetted or flooded in placa except for the outside 5 feet which shall be native soil backfilL
BUTTRESS OR
REPLACEMENT FILL
SUBDRAINS
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS D
® AGRA
STABILITY FILL / BUTTRESS DETAIL
KEY WIDTH
AS NOTED ON GRADING PLANS
is' MIN.
6' MIN.
OVERLAP
3/4'-1-1/2'
CLEAN GRAVEL
(3ft.3/ft. MIN.)
4- 0
NON-PERFORATED
PlPEs^
FILTER FABRIC
ENVELOPE (MIRAFI
140N OR APPROVED
EQUIVALENT)*
SEE T-CONNECTION
DETAIL
6' MIN.
COVER
PERFORATED
PIPE
4' MIN.
BEDDING
SUBDRAIN TRENCH DETAIL
*IF CALTRANS CLASS 2 PERMEABLE
MATERIAL IS USED IN PLACE OF
3y4'-1-1/2:' GRAVEL, FILTER FABRIC
MAY BE DELETED
SPECIFICATIONS FOR CALTRANS
CLASS 2 PERMEABLE MATERIAL
U.S. Standard
Sieve Size * Passing
1" 100
3/4" 90-100
3/8" 40-100
No. 4 25-40
No. 8 18-33
No. 30 5-15
No. 50 0-7
No. 200 0-3
Sand Equivalent>75
NOTES:
For buttress dimensions, see geotechnical report/plans. Actual dimensions of buttress and subdrain
may be changed by the geotechnical consultant based on field conditions.
SUBDRAIN INSTALLATIONrSubdraln pipe shouid be installed with perforations down as depicted.
At locations recommended by the geotechnicalvconsultant. nonperforated pipe should be Installed
SUBDRAIN TYPE-SubdraIn type should be Acrylon trile Butadiene Styrena (A.B.S.), Polyvinyl Chloride
(PVC) or approved equivalent. Class 125,SOR 32.5 should be used for maximum fill depths of 35 feet.
Class 200,SDfl 21 should be used for maximum fill depths of 100 feet. % AGRA
RETAINING WALL DRAINAGE DETAIL
SOIL BACKFILL. COMPACTED TO
90 PERCENT;RELATIVE COMPACTION*
RETAINING WALL-
WALL WATERPROOFING
PER ARCHlfECf''S
SPEbiFIC ATIONS^
FILTER FABRIC ENVELOPE
(MIRAFI 140N OR'APPROVED
EQUIVALENT);**
-3/4'-1-1/2* CLEAN GRAVEL
. V; (MIN.)_DIAMETER PERFORATED
PVC PIPE (SCHEDULE 40 OR
EQUIVALENT) WITH PERFORATIONS
O_RlEISITED,0OWN AS DEPICTED
MINIMUM 1; PERCENT GRADIENT
TO SUITABLE OUTLET
3' MIN.
SPECIFICATIONS FOR CALTRANS
CLASS 2 PERMEABLE MATERIAL
•S. Standard
Sieve Size * Passing
1" 100
3/4" 90-100
3/8" 40-100
No. 4 25-40
No. 8 18-33
No. 30 5-15
No. 50 0-7
No. 200 0-3
Sand Equivalent >75
COMPEfENT BEDROCK OR MATERIAL
AS EVALUATED BY THE GEOTECHNICAL
CONSULTANT
*BASED ON ASTM D1557
**IF CALTRANS CLASS 2 PERMEABLE MATERIAL
(SEE GRADATION TO LEFT) IS USED IN PLACE OF
3/4'-1-1/2' GRAVEL. FILTER FABRIC MAY BE
DELETED. CALTRANS CLASS 2 PERMEABLE
MATERIAL SHOULD BE COMPACTED TO 90
PERCENtfRELATlVE COMPACTION *
NOTE;COMPOSITE DRAINAGE PRODUCTS SUCH AS MIRADRAIN
OR J-DRAIN MAY BE USED AS AN ALTERNATIVE TO GRAVEL OR
CLASS 2. INSTALLATION SHOULD BE PERFOR^E^ IN ACCORDANCE}
WTTH MANUFACTURER'S SPECIRCATIONS.
^ AGRA