HomeMy WebLinkAboutGeotechnical InvestigationDUE DILLIGENCE GEOTECHNICAL
INVESTIGATION FOR THE PROPOSED
TENTATIVE TRACT 23064-4 LOCATED IN
THE REDHAWR AREA OF
RIVERSIDE COUNTY, CALIFORNIA
® INLAND, INC.
Geotechnical Consulting
INLAND, INC.
IGeotechnical Consulting
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DUE DILLIGENCE GEO TECHNICAL
INVESTIGATION FOR THE PROPOSED
TENTATIVE TRACT 23064-4 LOCATED IN
THE REDRAW %AREA OF
RIVERSIDE COUNTY, CALIFORNIA
Project No. 10 59 76-10
Dated: July 8, 2005
Prepared For:
Mr. John Neu
CENTEX HOMES
2280 Wardlow Circle, Suite 150
Corona, California 92880 -2896
1 41531 Date Street • Murrieta, CA • (951) 461 -1919 • Fax (951) 461 -7677
INLAND, INC.
' Geotechnical Consulting
July 8, 2005
Mr. John Neu
'CENTEX HOMES
2280 Wardlow Circle, Suite 150
Corona, California 92880 -2896
Project No. I05976 -10
Subject: Due - Diligence Geotechnical Investigation for the Proposed Tentative Tract 23064 -4, Located
' in the Redhawk Area of Riverside County, California
'LGC Inland, Inc. (LGC) is pleased to submit herewith our geotechnical investigation report for Tentative Tract
23065 -3, located in the Redhawk area of Riverside County, California. More specifically the site is located
'north of Deer Hollow Way and east of Corte Carmello. This work was performed in accordance with the scope
of work outlined in our proposal, dated June 9, 2005. This report presents the results of our field investigation,
laboratory testing and our engineering judgment, opinions, conclusions and recommendations pertaining to the
geotechnical design aspects of the proposed development.
It has been a pleasure to be of service to you on this project. Should you have any questions regarding the
content of this report or should you require additional information, please do not hesitate to contact this office at
your earliest convenience.
Respectfully submitted,
LGC INLAND, INC.
Mark Bergmann
President
CW /SMP /ts
IDistribution: (6) Addressee
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1 41531 Date Street • Murrieta, CA • (951) 461 -1919 • Fax (951) 461 -7677
TABLE OF CONTENTS
Section
Page
1.0 INTRODUCTION ..........................................................................................................
..............................I
1.1 Purpose and Scope of Services ................................................................................
............................... 1
'
1.2 Location and Site Description ..................................................................................
1.3 Proposed Development and Grading .......................................................................
............................... 1
............................... 3
2.0 INVESTIGATIONAND LABORA TOR Y TESTING .....................................................
............................... 3
2.1 Field Investigation ...................................................................................................
2.2 Laboratory Testing ...................................................................................................
............................... 3
............................... 3
2.3 Aerial Photograph Interpretation ............................................................................
............................... 4
'2.4
Historical Review of Aerial Photographs ................................................................
3.0 FINDINGS ...................................................................................................................
............................... 4
............................... 5
3.1 Regional Geologic Setting ........................................................................................
............................... 5
'
3.2 Local Geology and Soil Conditions .........................................................................
3.3 Groundwater .............................................................................................................
............................... 5
..............................7
3.4 Faul ting .....................................................................................................................
..............................7
'
3.5 Landslides ................................................................................................................
4.0 CONCLUSIONS AND RECOMMENDATIONS ..........................................................
............................... 7
............................... 7
4.1 General ......................................................................................................................
..............................7
4.2 Earthwork .................................................................................................................
4.2.1 General Earthwork and Grading Specifications .............................................
..:...........................7
............................... 7
4.2.2 Clearing and Grubbing ....................................................................................
............................... 7
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4.2.3 Excavation Characteristics ..............................................................................
4.2.4 Groundwater .....................................................................................................
............................... 8
..............................8
4.2.5 Ground Preparation — Fill Areas .....................................................................
............................... 8
4.2.6 Disposal of Oversize Rock ...............................................................................
............................... 8
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4.2.7 Fill Pl acement ..................................................................................................
............................... 8
4.2.8 Import Soils for Grading ..................................................................................
............................... 9
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4.2.9 Cut /Fill Transition Lots ...................................................................................
............................... 9
4.2.10 Processing of Cut Areas ...................................................................................
............................... 9
4.2.11 Shrinkage, Bulking and Subsidence .................................................................
............................... 9
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4.2.12 Geotechnical Observations ..............................................................................
.............................10
4.3 Post Grading Considerations .................................................................................
............................... 10
4.3.1 Slope Landscaping and Maintenance ............................................................
............................... 10
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4.3.2 Site Drainage .................................................................................................
............................... 10
5.0 SEISMIC DESIGN CONSIDERATIONS ...................................................................
............................... 11
5.1 Ground Motions .......................................................................................................
.............................11
5.2 Secondary Seismic Hazards ...................................................................................
............................... 12
5.3 Liquefaction ...........................................................................................................
............................... 12
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60 TENTA TIVE FOUNDA TIONDESIGN RECOMMENDA TIONS .............................................................
6.1 General ............................................... ...............................
.............................13
13
62 Allowable Bearing Values ......................................................................................
............................... 13
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6.3 Settlement .................................................................................................................
6.4 Lateral Resistance ..................................................................................................
.............................13
............................... 13
6.5 Footing Observations .............................................................................................
............................... 14
'
6.6 Expansive Soil Considerations ...............................................................................
6.61 Very Low Expansion Potential (Expansion Index of 20 or Less) ...................
............................... 14
............................... 14
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66.1.1 Footings ......................................................................................................... ...............................
14
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6.6.1.2 Building Floor Slabs ...................................................................................... ...............................
15
6.6.2" Low Expansion Potential (Expansion Index of 21 to 50) ....................................... ...............................
16
66.2.1 Footings ......................................................................................................... ...............................
16
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6.62.2 Building Floor Sl abs ...................................................................................... ...............................
16
6.63 Medium Expansion Potential (Expansion Index of 51 to 90) ................................ ...............................
17
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66.3.1 Footings ......................................................................................................... ...............................
6.63.2 Building Floor Slabs ...................................................................................... ...............................
17
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67 Post Tensioned Slab /Foundation Design Recommendations ................................. ...............................
19
68 Corrosivity to Concrete and Metal ........................................................................ ...............................
69 Structural Setbacks ................................................................................................. ...............................
20
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7.0 RETAINING WALLS .................................................................................................. ...............................
21
7.1 Active and At -Rest Earth Pressures ....................................................................... ...............................
21
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7.3 Temporary Excavations ......................................................................................... ...............................
22
7.4 Wall Backfill ........................................................................................................... ...............................
22
8.0 CONCRETE FLATWORK ......................................................................................... ...............................
22
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8.1 Thickness and Joint Spacing .................................................................................. ...............................
22
8.2 Subgrade Preparation ............................................................................................ ...............................
23
PRELIMINARY ASPHALTIC CONCRETE PAVEMENT DESIGN ........................... ...............................
23
'9.0
10.0 SLOPE STABILITY ANALYSIS .................................................................................. ...............................
24
10.1 Potential Deep Seated Failures ............................................................................. ...............................
24
Potential Surficial Failures .................................................................................... ...............................
24
'10.1
11.0 GRADING PLANREVIEWAND CONSTRUCTION SERVICES .............................. ...............................
24
12.0 INVESTIGATION LIMITATIONS .............................................................................. ...............................
25
Attachments:
Figure 1— Site Location Map (Page 2)
Figure 2 — Regional Geologic Map (Page 6)
APPENDIX A — References (Rear of Text)
APPENDIX B — Fault Trench and Boring Logs (Rear of Text)
APPENDIX C — Laboratory Testing Procedures and Test Results (Rear of Text)
APPENDIX D — Seismicity (Rear of Text)
APPENDIX E — Asphaltic Concrete Pavement Calculations (Rear of Text)
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APPENDIX F — General Earthwork and Grading Specifications (Rear of Text)
APPENDIX G — Historical Aerial Photographs (Rear of Text)
Plate 1— Geotechnical Map an Pocket)
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Project No. 105976-10 Page ii July 8, 2005
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1.0 INTRODUCTION
LGC Inland, Inc. (LGC) is pleased to present this geotechnical investigation report for the subject property.
The purposes of this investigation were to determine the nature of surface and subsurface soil conditions,
evaluate their in -place characteristics, and then provide preliminary grading and foundation design
recommendations based on the accompanying site map provided by you. The general location of the property is
indicated on the Site Location Map (Figure 1). The Tentative Tract Map you provided was used as the base
map to show geologic conditions within the subject site (see Geotechnical Map, Plate 1).
1.1 Purpose and Scone of Services
The purposes of this investigation were to obtain information on the surface /subsurface soil and geologic
' conditions within the subject site, evaluate the data, and then provide preliminary grading and
foundation design recommendations. The scope of our investigation included the following:
' Review of readily available published and unpublished literature and geologic maps pertaining to
active and potentially active faults that lie in close proximity to the site which may have an impact
on the proposed development (see Appendix A, References).
' Field reconnaissance to observe existing site conditions and coordinate with Underground Service
Alert to locate any known underground utilities.
' Geologic mapping of the site.
' Excavating, logging, and selective sampling of five (5) test pits to depths of 10 to 14 feet.
Exploration locations are shown on the enclosed Geotechnical Map (Plate 1) and descriptive logs are
presented in Appendix B.
Laboratory testing and analysis of representative samples of soil materials (bulk and undisturbed)
obtained during exploration to determine their engineering properties (Appendix C).
' Engineering and geologic analysis of the data with respect to the proposed development.
' An evaluation of faulting and seismicity of the region as it pertains to the site (Appendix D).
• Preliminary asphaltic concrete pavement analysis (Appendix E).
Preparation of General Earthwork and Grading Specifications (Appendix F).
• Preparation of this report presenting our findings, conclusions and preliminary geotechnical
recommendations for the proposed development.
' 1.2 Location and Site Description
' The subject site is located in the Redhawk area of Riverside County, California. More specifically the
site is located north of Deer Hollow Way and east of Corte Carmello. An existing golf course green belt
is present between the site and Corte Carmello. The general location and configuration of the site is
' shown on the Site Location Map (Figure 1).
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CENTEX TRACT 23064-4
Project No.
105976-10
LGC FIGURE 1
Geol./ En g.
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SITE LOCATION MAP
Scale
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INLAND
Date
July 2005
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The topography of the site is moderately steep. The general elevation of the property is 1,200 feet above
mean sea level (msl) with differences of over 120± feet across the entire site. Local drainage is
"generally directed to the northeast.
' No underground structures are known to exist at the site. The property is currently undeveloped vacant
land. Many of the ridge tops have been cut down and the earth materials used on adjacent sites.
Properties to the northwest, south, and west of the site are developed with single family residences,
while the area to the east primarily consists of undeveloped land. Golf course green belts are present
immediately to the west and northeast of the subject property. Vegetation consists of a moderate cover
of annual weeds /grasses and small brush.
1 1.3 Proposed Development and Grading
' The proposed residential development is expected to consist of wood framed one- and two -story
structures utilizing slab on ground construction with associated streets, landscape areas, and utilities.
The proposed development includes 108 lots scattered throughout the site. The project includes several
' areas that will remain as open space. Formal plans have not been prepared and await the conclusions
and recommendations of this report.
' The Rough Grading Plan, provided by you, was utilized in our investigation and forms the base for our
Geotechnical Map (Plate 1). LGC assumes that the existing retention basin will be filled with
' compacted fill. Cuts and fills should be less than 65 feet in height.
2.0 INVESTIGATION AND LABORATORY TESTING
2.1 Field Investigation
' Subsurface exploration within the subject site was performed on June 16, 2005. A backhoe was utilized
to excavate five (5) test pits to a maximum depth of 14 feet. Prior to the subsurface work, an
' underground utilities clearance was obtained from Underground Service Alert of Southern California.
Earth materials encountered during exploration were classified and logged in general accordance with
' the visual -manual procedures of ASTM D 2488. The approximate exploration locations are shown on
Plate 1 and descriptive logs are presented in Appendix B.
' Associated with the subsurface exploration was the collection of bulk (disturbed) samples and relatively
undisturbed samples of soil materials for laboratory testing. The central portions of the driven -core
samples were placed in sealed containers and transported to our laboratory for testing.
' 2.2 Laboratory Testing
Maximum dry density/optimum moisture content, expansion potential, R- value, corrosivity, and in -situ
density/moisture content were determined for selected undisturbed and bulk samples of soil materials,
considered representative of those encountered. A brief description of laboratory test criteria and
' summaries of test data are presented in Appendix C. An evaluation of the test data is reflected
throughout the Conclusions and Recommendations section of this report.
1 Project No. 105976 -10 Page 3 July 8, 2005
2.3 Aerial Photograph Interpretation
No strong geomorphic lineaments were interpreted to project through the site during our review of aerial
' photographs of the subject property. Geomorphic evidence of active landsliding was not observed on
the site. A table summarizing the aerial photographs utilized in our geomorphic interpretation of
lineaments and landslides is included in Appendix A - Aerial Photograph Interpretation Table and
scanned copies of some of the aerial photographs are included in Appendix G.
' 2.4 Historical Review ofAerial Photographs
Aerial photographs were reviewed to evaluate past land use patterns of the subject property and vicinity.
' The photos were obtained from the Riverside County Flood Control & Water Conservation District, and
have been reproduced and included in Appendix G. This review revealed the following:
1 1974: The subject property appears to be vacant undeveloped land. North: Undeveloped vacant land.
East: Undeveloped vacant land. South: Undeveloped vacant land. West: Undeveloped vacant land.
Further to the west the land was being used for agriculture.
' 1980: The subject property appears to be vacant undeveloped land. North: Undeveloped vacant land.
East: Undeveloped vacant land. South: Undeveloped vacant land. West: Undeveloped vacant land.
' Further to the west the land was being used for agriculture.
1983: The subject property appears to be vacant undeveloped land. North: Undeveloped vacant lan d.
East: Undeveloped, vacant land. South: Undeveloped vacant land. West: Undeveloped vacant land.
Further to the west the land was being used for agriculture.
1990: The subject property appears to be vacant undeveloped land with grading in progress within the
northern portion of the site. North: Golf course present and grading in progress to the northwest. East:
Primarily undeveloped vacant land with a recent access road and minor grading to the northeast present.
' South: Undeveloped vacant land with minor grading to the southwest. West: Golf course present and
grading in progress along Corte Carmello. Further to the west the land was being used for agriculture.
' 1995: The subject property appears to be vacant undeveloped land with grading in progress within the
northern portion of the site. North: Golf course present and grading in progress to the northwest. East:
Primarily undeveloped vacant land with a recent access road. South: Undeveloped vacant land. West:
' Golf course present and grading in progress along Corte Carmello. Further to the west the land was
being used for agriculture.
' 2000: The subject property appears to be vacant undeveloped land. North: Golf course present and
single family residences to the northwest. East: Primarily undeveloped vacant land. South:
Undeveloped vacant land. West: Golf course present and single family residences present along Corte
Carmello. Further to the west the land was being used for agriculture.
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' Project No. 105976 -10 Page 4 July 8, 2005
3.0 FINDINGS
! 3.1 "Regional Geologic Setting
' Regionally, the site is located in the Peninsular Ranges Geomorphic Province of California. The
Peninsular Ranges are characterized by steep, elongated valleys that trend west to northwest. The
' northwest - trending topography is controlled by the Elsinore fault zone, which extends from the San
Gabriel River Valley southeasterly to the United States/Mexico border. The Santa Ana Mountains lie
along the western side of the Elsinore fault zone, while the Perris Block is located along the eastern side
! of the fault zone. The mountainous regions are underlain by Pre - Cretaceous, metasedimentary and
metavolcanic rocks and Cretaceous plutonic rocks of the Southern California Batholith. Tertiary and
Quaternary rocks are generally comprised of non - marine sediments consisting of sandstone, mudstones,
! conglomerates, and occasional volcanic units. A map of the regional geology is presented on the
Regional Geologic Map, Figure 2.
3.2 Local Geology and Soil Conditions
The earth materials on the site are primarily comprised of artificial fill, Quaternary alluvial and colluvial
deposits, and bedrock. A general description of the earth materials observed on the site is provided in
' the following paragraphs:
• Artificial Fill, Undocumented (map symbol AM: Undocumented artificial fill materials were
' observed throughout the site. These materials are typically locally derived from the native materials
and are expected to consist generally of silty sand to clayey sand with gravel and cobbles. These
materials are typically inconsistent, poorly consolidated fills.
' Compacted Artificial Fill (map symbol Afc): According to Petra (2002), "compacted engineered
fill was placed around the golf course during grading of the golf course and maintenance building in
1989. Petra provided the geotechnical observation and testing services for the project. The
engineered fill consists of sand and silty sands derived from the Pauba Formation bedrock and its
overlying colluvial and alluvial soils. At the time of placement it was at or near - optimum moisture
iand was compacted to a minimum relative density of 90 percent."
• Quaternary Alluvium (map symbol Oal): Quaternary alluvial deposits were encountered in the
' previous Petra study and were noted in broad, gently sloping areas. These deposits are generally
loosely consolidated clayey sand to silty sand materials.
! Quaternary Colluvial Deposits (map symbol Ocol): Quaternary colluvial deposits were encountered
in the previous Petra study and were noted in broad, gently sloping areas. These deposits are
generally loosely consolidated clayey sand to silty sand materials.
! Quaternary Very Old Axial Channel Deposits (map symbol Ovoa): Quaternary very old axial
channel deposits were encountered to a maximum depth of 14 feet. These earth materials are the
' equivalent to the terrace deposits mapped by Petra. These deposits consist predominately of reddish
brown, clayey sand with cobbles and occasional silty sand with cobbles. This unit is generally
slightly moist to moist and medium dense to dense in condition.
' Quaternary Pauba Formation: Pauba Formation bedrock was mapped generally at depth below the
very old axial channel deposits. The bedrock primarily consists of light olive gray, fine to coarse
! grained clayey sandstone with varying amounts of silt and clay. These materials are typically
moderately hard to hard and slightly moist to moist.
' Project No. 105976-10 Page 5 July 8, 2005
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' 3.3 Groundwater
Groundwater was not encountered to the maximum depth explored, approximately 14 feet.
1 3.4 Faulting
1 The geologic structure of the entire Southern California area is dominated by northwest - trending faults
associated with the San Andreas Fault system. Faults, such as the Newport- Inglewood, Whittier -
1 Elsinore, San Jacinto and San Andreas are major faults in this system and all are known to be active. In
addition, the San Andreas, Elsinore, and San Jacinto faults are known to have ruptured the ground
surface in historic times.
Based on our review of published and unpublished geologic maps and literature pertaining to the site
and regional geology, the closest active fault producing the highest anticipated peak ground acceleration
' at site is the Elsinore - Temecula Fault located approximately 0.1 kilometers to the southwest. This fault
is capable of producing a moderate magnitude earthquake. No active faults are known to project
through the site and the site does not lie within an Alquist -Priolo Earthquake Fault Zone (previously
' called an Alquist -Priolo Special Studies Zone).
3.5 Landslides
No landslide debris was noted during our subsurface exploration and no ancient landslides are known to
exist on the site.
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4.0 CONCLUSIONS AND RECOMMENDATIONS
4.1 General
' From a soils engineering and engineering geologic point of view, the subject property is considered
suitable for the proposed development, provided the following conclusions and recommendations are
incorporated into the design criteria and project specifications.
' 4.2 Earthwork
4.2.1 General Earthwork and Grading Specifications
All earthwork and grading should be performed in accordance with all applicable requirements
1 of the Grading and Excavation Code and the Grading Manual of the appropriate reviewing
agency, in addition to the provisions of the 1997 Uniform Building Code (UBC), including
Appendix Chapter 33. Grading should also be performed in accordance with applicable
1 provisions of the General Earthwork and Grading Specifications (Appendix F), prepared by
LGC, unless specifically revised or amended herein.
1 4.22 Clearinz and Grubbing
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1 Project No. 105976-10 Page 7 July 8, 2005
All weeds, grasses, brush, shrubs, debris and trash in the areas to be graded should be stripped
and hauled offsite. During site grading, laborers should clear from fills any roots, branches, and
other deleterious materials missed during clearing and grubbing operations.
The project geotechnical engineer or his qualified representative should be notified at appropriate
' times to provide observation and testing services during clearing operations and to verify
compliance with the above recommendations. In addition, any buried structures or unusual or
' adverse soil conditions encountered that are not described or anticipated herein should be
brought to the immediate attention of the geotechnical consultant.
' 4.2.3 Excavation Characteristics
Based on the results of our exploration, the near surface soil materials, will be readily excavated
' with conventional earth moving equipment. However, localized hard bedrock could be
encountered.
' 4.2.4 Groundwater
Groundwater was not encountered during our subsurface exploration. Therefore, groundwater is
' not expected to be a factor during grading or construction. However, localized groundwater
could be encountered during construction due to the limited number of exploratory locations or
other factors.
4.2.5 Ground Preparation —Fill Areas
All existing low density and potentially collapsible soil materials, such as any topsoil, loose
alluvial/colluvial deposits, and loose manmade fill, should be removed to underlying competent
bedrock, from each area to receive compacted fill. Dense native soils are subject to verification
' by the project engineer, geologist or their representative. Prior to placing structural fills, the
exposed bottom surfaces in each removal area should first be scarified to a depth of 6 inches or
more, watered or air dried as necessary to achieve near - optimum moisture conditions and then
' re- compacted in -place to a minimum relative compaction of 90 percent.
Based on LGC's exploration, anticipated depths of removal are shown on the enclosed
' Geotechnical Map (Plate 1). In general, the anticipated removal depths should vary from 3 to 14
feet. However, actual depths and horizontal limits of any removals will have to be determined
during grading on the basis of in- grading observations and testing performed by the geotechnical
Iconsultant and/or engineering geologist.
4.26 Disposal of Oversize Rock
Oversize rock is expected to be encountered during grading. Therefore, oversize rock, (i.e., rock
exceeding a maximum dimension of 12 inches) will require special handling, such as offsite
disposal or stockpiled onsite and crushed for future use. The disposal of oversize rock is
discussed in General Earthwork and Grading Specifications, Appendix F.
' 4.2.7 Fill Placement
' Any fill should be placed in 6- to 8 -inch maximum (uncompacted) lifts, watered or air dried as
necessary to achieve uniform near optimum moisture content (preferred at or slightly above
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' Project No. 1059 76-10 Page 8 July 8, 2005
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optimum moisture content) and then compacted in -place to a minimum of 90 percent relative
compaction. The laboratory maximum dry density and optimum moisture content for each
change in soil type should be determined in accordance with ASTM Test Method D1557 -00.
4.28 Import Soils for Grading
In the event import soils are needed to achieve final design grades, all potential import materials
should be free of deleterious /oversize materials, non - expansive, and approved by the project
geotechnical consultant prior to commencement of delivery onsite.
4.29 Cut/Fill Transition Lots
To mitigate distress to structures related to the potential adverse affects of excessive differential
settlement, cut/fill transitions should be eliminated from all building areas where the depth of fill
placed within the "fill" portion exceeds proposed footing depths. The entire structure should be
founded on a uniform bearing material. This should be accomplished by overexcavating the
"cut" portion and replacing the excavated materials as properly compacted fill. Recommended
depths of overexcavation are provided in the following table:
Up to 5 feet Equal Depth
5 to 10 feet 5 feet
Greater than 10 feet One -half the thickness of fill placed on the "fill' portion (10
feet maximum)
Overexcavation of the "cut' portion should extend beyond the perimeter building lines a
horizontal distance equal to the depth of overexcavation or to a minimum distance of 5 feet,
whichever is greater.
i4.2.10 Processing of Cut Areas
' Where low- density surficial soil deposits (undocumented artificial fills, topsoil, colluvium and
alluvium) are not removed in their entirety in cut areas, these materials should be removed to
competent bedrock and replaced as properly compacted fill. Competent bedrock should be
exposed at final grade or the entire lot should be overexcavated and replaced with compacted fill.
In addition, final determination of lots that require overexcavation due to rock or transition
conditions should be determined in the field.
4.2.11 Shrinkage, Bulking and Subsidence
' Volumetric changes in earth quantities will occur when excavated onsite earth materials are
replaced as properly compacted fill. The following is an estimate of shrinkage and bulking
factors for the various geologic units found onsite. These estimates are based on in -place
' densities of the various materials and on the estimated average degree of relative compaction
achieved during grading.
Project No. 1059 76-10 Page 9 July 8, 2005
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Subsidence from scarification and recompaction of exposed bottom surfaces in removal areas to
ireceive fill is expected to vary from negligible to approximately 0.1 -foot.
The above estimates of shrinkage and subsidence are intended as an aid for project engineers in
i determining earthwork quantities. However, these estimates should be used with some
caution since they are not absolute values. Contingencids should be made for balancing
iearthwork quantities based on actual shrinkage and subsidence that occurs during grading.
4.212 Geotechnical Observations
iAn observation of clearing operations, removal of unsuitable materials, and general grading
procedures should be performed by the project geotechnical consultant or his representative.
iFills should not be placed without prior approval from the geotechnical consultant.
The project geotechnical consultant or his representative should also be present onsite during all
' grading operations to verify proper placement and adequate compaction of all fill materials, as
well as to verify compliance with the other recommendations presented herein.
_i 4.3 Post Grading Considerations
4.3.1 Slope Landscaping and Maintenance
' Adequate slope and pad drainage facilities are essential in the design of the finish grading for the
subject site. An anticipated rainfall equivalency of 60 to 100 inches per year at the site can result
due to irrigation. The overall stability of graded slopes should not be adversely affected
provided all drainage provisions are properly constructed and maintained thereafter and provided
all engineered slopes are landscaped with a deep rooted, drought tolerant and maintenance free
' plant species, as recommended by the project landscape architect. Additional comments and
recommendations are presented below with respect to slope drainage, landscaping and irrigation.
A discussion of drainage is given in the following section.
4.3.2 Site Drainage
Positive - drainage devices, such as sloping sidewalks, graded swales and/or area drains, should be
provided around buildings to collect and direct all water away from the structures. Pad drainage
should be designed for at least the minimum gradient required by the UBC with drainage
directed to the adjacent drainage facilities or other location approved by the building official.
Ground adjacent to foundations shall be graded so that it is sloped away from the building at
least 12:1 horizontal to vertical (h:v) (4.8 °) for a minimum distance of 6 feet, or another
' alternative approved way shall be found to divert water from the foundation. Neither rain nor
excess irrigation water should be allowed to collect or pond against building foundations. Roof
gutters and downspouts may be required on the sides of buildings where yard drainage devices
icannot be provided and/or where roof drainage is directed onto adjacent slopes. All drainage
should be directed to adjacent driveways, adjacent streets or storm -drain facilities.
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iProject No. 1059 76-10 Page 10 July 8, 2005
4.3.3 Utility Trenches
All utility trench backfill within the street right -of -ways, utility easements, under sidewalks,
driveways and building floor slabs, as well as within or in proximity to slopes should be
' compacted to a minimum relative compaction of 90 percent. Where onsite soils are utilized as
backfill, mechanical compaction will be required. Density testing, along with probing, should be
performed by the project geotechnical engineer or their representative to verify proper
compaction.
1 For deep trenches with vertical walls, backfill should be placed in approximately 8- to 10 -inch
maximum lifts and then mechanically compacted with a hydro - hammer, pneumatic tampers or
similar equipment. For deep trenches with sloped walls, backfill materials should be placed in
1 approximately 8- to 10 -inch maximum lifts and then compacted by rolling with a sheepsfoot
tamper or similar equipment.
' To avoid point loads and subsequent distress to vitrified clay, concrete or plastic pipe, imported
sand bedding should be placed at least 1 -foot above the pipe in areas where excavated trench
materials contain significant cobbles. Sand - bedding materials should be thoroughly jetted prior
' to placing the backfill.
Where utility trenches are proposed parallel to any building footing (interior and/or exterior
trenches), the bottom of the trench should not be located within a 1:1 (h:v) plane projected
downward from the outside bottom edge of the adjacent footing.
5.0 SEISMIC DESIGN CONSIDERATIONS
'
5.1 Ground Motions
Structures within the site should be designed and constructed to resist the effects of seismic ground
motions as provided in the 1997 UBC Sections 1626 through 1633. The method of design is dependent
on the seismic zoning, site characteristics, occupancy category, building configuration, type of structural
system and building height.
For structural design in accordance with the 1997 UBC, a computer program developed by Thomas F.
Blake (UBCSEIS, 1998) was used that compiles fault information for a particular site using a modified
' version of a data file of approximately 183 California faults that were digitized by the California
Division of Mines and Geology and the U.S. Geological Survey. This program computes various
information for a particular site, including; the distance of the site from each of the faults in the data file,
the estimated slip rate for each fault and the "maximum moment magnitude" of each fault. The program
then selects the closest Type A, Type B and Type C faults from the site and computes the seismic design
coefficients for each of the fault types. The program then selects the largest of the computed seismic
design coefficients and designates these as the design coefficients for the subject site.
The probabilistic seismic hazard analysis for the site was completed for three (3) different attenuation
relationships (Campbell & Bozorgnia, 1997, Sadigh et al., 1997, and Abrahamson & Silva, 1997). The
peak ground acceleration value of 0.68 g is the mean of the three (3) values obtained. The probability of
' exceedance versus acceleration waves for the different attenuation relationships are presented in
Appendix D. 0
Project No. 105976-10 Page 11 July 8, 2005
I
Probability curves were calculated using the computer program FRISKSP Version 4.0 (Blake, 2000).
Based on our evaluation, the Elsinore - Temecula Fault zone would probably generate the most severe
' site ground motions with an anticipated maximum moment magnitude of 6.8 and anticipated slip rate of
5 mm/yr. The following 1997 UBC seismic design coefficients should be used for the proposed
structures. These criteria are based on the soil profile type as determined by subsurface geologic
conditions, on the proximity of the Elsinore - Temecula Fault and on the maximum moment magnitude
and slip rate.
1
i
1
-1
1 5.2
J�
1
I
1
1
Figure 16 -2 Seismic Zone
4
Table 16 -I Seismic Zone Factor Z
0.4
Table 16 -U Seismic Source Type
B
Table 16 -J Seismic Profile Type
So
Table 16 -5 Near- Source Factor, N.
1.3
Table 16 -T Near - Source Factor, N„
1.6
Table 16 -Q Seismic Coefficient, C.
0.57
Table 16 -R Seismic Coefficient, C,
1.02
Secondary Seismic Hazards
Secondary effects of seismic activity normally considered as possible hazards to a site include several
types of ground failure as well as induced flooding. Various general types of ground failures, which
might occur as a consequence of severe ground shaking of the site, include land sliding, ground
lurching, shallow ground rupture, and liquefaction. The probability of occurrence of each type of
ground failure depends on the severity of the earthquake, distance from faults, topography, subsurface
soils, groundwater conditions, and other factors. Based on our subsurface exploration, all of the above
secondary effects of seismic activity are considered unlikely.
Seismically induced flooding normally includes flooding due to a tsunami (seismic sea wave), a seiche
(i.e., a wave -like oscillation of the surface of water in an enclosed basin that may be initiated by a strong
earthquake) or failure of a major reservoir or retention structure upstream of the site. Since the site is
located more than 20 miles inland from the nearest coastline of the Pacific Ocean at an elevation in
excess of 1,200 feet above mean sea level, the potential for seismically induced flooding due to a
tsunamis run -up is considered nonexistent. Since no enclosed bodies of water lie adjacent to the site, the
potential for induced flooding at the site due to a seiche is also considered nonexistent.
1 5.3 Liquefaction
1
i
1
Liquefaction involves the substantial loss of shear strength in saturated soil, usually taking place within
a soil medium exhibiting a uniform, fine grained characteristic, loose consistency and low confining
pressure when subjected to impact by seismic or dynamic loading. Factors influencing a site's potential
for liquefaction include area seismicity, onsite soil type and consistency and groundwater level. The
project site will be underlain by compacted fill and bedrock. The potential for earthquake induced
liquefaction within the site is considered very low to remote due to the recommended engineered fill,
relatively low groundwater, and the shallow bedrock.
Project No. 105976-10 Page 12 July 8, 2005
6.0 TENTATIVE FOUNDATIONDESIGNRECOMMENDATIONS
6.1 "General
' Provided site grading is performed in accordance with the recommendations of this report, conventional
shallow foundations are considered feasible for support of the proposed structures. Tentative foundation
recommendations are provided herein. However, these recommendations may require modification
depending on as- graded conditions existing within the building site upon completion of grading.
62 Allowable Bearing Values
An allowable bearing value of 1,500 pounds per square foot (psf) is recommended for design of 24 -inch
1 square pad footings and 12 -inch wide continuous footings founded at a minimum depth of 12 inches
below the lowest adjacent final grade. This value may be increased by 20 percent for each additional
1 -foot of width and/or depth to a maximum value of 2,500 psi Recommended allowable bearing values
include both dead and live loads and may be increased by one -third when designing for short duration
wind and seismic forces.
' 6.3 Settlement
Based on the general settlement characteristics of the soil types that underlie the building sites and the
' anticipated loading, it has been estimated that the maximum total settlement of conventional footings
will be less than approximately '/< -inch. Differential settlement is expected to be about %Z -inch over a
horizontal distance of approximately 20 feet, for an angular distortion ratio of 1:480. It is anticipated
that the majority of the settlement will occur during construction or shortly thereafter as loads are
applied.
' The above settlement estimates are based on the assumption that the grading and construction is
performed in accordance with the recommendations presented in this report and that the project
geotechnical consultant will observe or test the soil conditions in the footing excavations.
6.4 Lateral Resistance
' A passive earth pressure of 250 psf per foot of depth to a maximum value of 2,500 psf may be used to
determine lateral bearing resistance for footings. Where structures are planned in or near descending
slopes, the passive earth pressure should be reduced to 150 psf per foot of depth to a maximum value of
' 1,500 psf. In addition, a coefficient of friction of 0.40 times the dead load forces may be used between
concrete and the supporting soils to determine lateral sliding resistance. The above values may be
increased by one -third when designing for short duration wind or seismic forces.
The above values are based on footings for an entire structure being placed directly against compacted
fill. In the case where footing sides are formed, all backfill placed against the footings should be
' compacted to a minimum of 90 percent of maximum dry density
1 ,5
IProject No. 1059 76-10 Page 13 July 8, 2005
6.5 Footine Observations
' All foundation excavations should be observed by the project geotechnical engineer to verify that they
have been excavated into competent bearing materials. The foundation excavations should be observed
' prior to the placement of forms, reinforcement or concrete. The excavations should be trimmed neat,
level and square. All loose, sloughed or moisture- softened soil should be removed prior to concrete
placement.
' Materials from footing excavations should not be placed in slab on grade areas unless the soils are
compacted to a minimum 90 percent of maximum dry density.
66 Expansive Soil Considerations
Results of our preliminary laboratory tests and tests performed by Petra indicate onsite earth materials
exhibit expansion potentials ranging from VERY LOW to MEDIUM as classified in accordance with
1997 UBC Table 18 -I -B. Accordingly, expansive soil conditions should be evaluated for individual lots
during and at the completion of rough grading. The design and construction details herein are intended
to provide recommendations for the various levels of expansion potential, which may be evident at the
completion of rough grading.
6.6.1 Very Low Expansion Potential (Expansion Index of 20 or Less)
' Results of our laboratory tests indicate onsite soils exhibit a VERY LOW expansion potential as
classified in accordance with Table 18 -I -B of the 1997 Uniform Building Code (UBC). Since
' the onsite soils exhibit expansion indices of 20 or less, the design of slab on ground foundations
is exempt from the procedures outlined in Section 1815. Based on the above soil conditions, it is
recommended that footings and floors be constructed and reinforced in accordance with the
' following minimum criteria. However, additional slab thickness, footing sizes and/or
reinforcement should be provided as required by the project architect or structural engineer.
6.6.1.1 Foodnrs
• Exterior continuous footings may be founded at the minimum depths indicated in UBC
Table 184-C (i.e. 12 -inch minimum depth for one -story and 18 -inch minimum depth for
two -story construction). Interior continuous footings for both one- and two -story
construction may be founded at a minimum depth of 12 inches below the lowest adjacent
' grade. All continuous footings should have a minimum width of 12 and 15 inches, for
one -story and two -story buildings, respectively, and should be reinforced with two (2)
No. 4 bars, one (1) top and one (1) bottom.
• Exterior pad footings intended for the support of roof overhangs, such as second story
decks, patio covers and similar construction should be a minimum of 24 inches square
' and founded at a minimum depth of 18 inches below the lowest adjacent final grade. No
special reinforcement of the pad footings will be required.
IProject No. 105976 -10 Page 14 July 8, 2005
t£ 6.1.2 Building Floor Slabs
Concrete floor slabs should be 4 inches thick and reinforced with either 6 -inch by 6 -inch,
No. 6 by No. 6 welded wire mesh (6x6- W2.9xW2.9); or with No. 3 bars spaced a
' maximum of 24 inches on center, both ways. All slab reinforcement should be supported
on concrete chairs or bricks to ensure the desired placement near mid- depth.
1 Interior floor slabs with moisture sensitive floor coverings should be underlain by a
15 -mil thick moisture /retarder to help reduce the upward migration of moisture from the
' underlying subgrade soils. The moisture/vapor barrier product used should meet the
performance standards of an ASTM E 1745 Class A material, and be properly installed in
accordance with ACI publication 302. It is the responsibility of the contractor to ensure
that the moisture/vapor barrier systems are placed in accordance with the project plans
and specifications, and that the moisture /vapor retarder materials are free of tears and
punctures prior to concrete placement. Additional moisture reduction and/or prevention
' measures may be needed, depending on the performance requirements of future interior
floor coverings.
' Recommendations are traditionally included with geotechnical foundation
recommendations or sand layers placed below slabs and aboveibelow vapor barriers and
retarders for the purpose of protecting the barrier /retarder and to assist in concrete curing.
1 Sand layer requirements are the purview of the foundation engineer /structural engineer,
and should be provided in accordance with ACI Publication 302 "Guide for Concrete
Floor and Slab Construction ". We have provided recommendations in Table 1 that we
' consider to be a minimum from a geotechnical perspective. These recommendations must
be confirmed (and/or altered) by the foundation engineer, based upon the performance
expectations of the foundation. Ultimately, the design of the moisture retarder system and
' recommendations for concrete placement and curing are the purview of the foundation
engineer, in consideration of the project requirements provided by the architect and
developer.
• Garage area floor slabs should be 4 inches thick and should be reinforced in a similar
manner as living area floor slabs. Garage area floor slabs should also be placed
separately from adjacent wall footings with a positive separation maintained with % -inch
minimum felt expansion joint materials and quartered with weakened plane joints. A
12 -inch wide grade beam founded at the same depth as adjacent footings should be
provided across garage entrances. The grade beam should be reinforced with a minimum
of two (2) No. 4 bars, one (1) top and one (1) bottom.
' Prior to placing concrete, the subgrade soils below all floor slabs should be pre - watered
to promote uniform curing of the concrete and minimize the development of shrinkage
cracks.
\k
1 Project No. 1059 76-10 Page 15 July 8, 2005
6.6.2 Low Expansion Potential (Expansion Index of 21 to 50
' Onsite soils may exhibit a LOW expansion potential as classified in accordance with Table
18 -I -B of the 1997 Uniform Building Code (UBC). The 1997 UBC specifies that slab on ground
foundations (floor slabs) resting on soils with expansion indices greater than 20, require special
design considerations in accordance with 1997 UBC Section 1815. The design procedures
outlined in 1997 UBC Section 1815 are based on the thickness and plasticity index of each
different soil type existing within the upper 15 feet of the building site. For preliminary design
purposes, we have assumed an effective plasticity index of 15 for in accordance with 1997 UBC
Section 1815.4.2.
6.6.2.1 Footings
• Exterior continuous footings may be founded at the minimum depths indicated in UBC
Table 18 -I -C (i.e. 12 -inch minimum depth for one -story and 18 -inch minimum depth for
two -story construction). Interior continuous footings for both one- and two -story
construction may be founded at a minimum depth of 12 inches below the lowest adjacent
' grade. All continuous footings should have a minimum width of 12 and 15 inches, for
one -story and two -story buildings, respectively, and should be reinforced with a
minimum of two (2) No. 4 bars, one (1) top and one (1) bottom.
• Exterior pad footings intended for the support of roof overhangs, such as second story
decks, patio covers and similar construction should be a minimum of 24 inches square
' and founded at a minimum depth of 18 inches below the lowest adjacent final grade. The
pad footings should be reinforced with No. 4 bars spaced a maximum of 18 inches on
center, both ways, near the bottom -third of the footings.
6.6.2.2 Building Floor Slabs
• The project architect or structural engineer should evaluate minimum floor slab thickness and
reinforcement in accordance with 1997 UBC Section 1815 based on an effective plasticity index
of 15. Unless a more stringent design is recommended by the architect or the structural engineer,
we recommend a minimum slab thickness of 4 inches for both living area and garage floor slabs,
and be reinforced with either 6 -inch by 6 -inch, No. 6 by No. 6 welded wire mesh
(6x6- W2.9xW2.9); or with No. 3 bars spaced a maximum of 18 inches on center, both ways. All
' slab reinforcement should be supported on concrete chairs or bricks to ensure the desired
placement near mid- depth.
1 • Interior floor slabs with moisture sensitive floor coverings should be underlain by a 15 -mil thick
moisture /retarder to help reduce the upward migration of moisture from the underlying subgrade
' soils. The moisture/vapor barrier product used should meet the performance standards of an
ASTM E 1745 Class A material, and be properly installed in accordance with ACI publication
302. It is the responsibility of the contractor to ensure that the moisture /vapor barrier systems are
placed in accordance with the project plans and specifications, and that the moisture /vapor
retarder materials are free of tears and punctures prior to concrete placement. Additional
moisture reduction and/or prevention measures may be needed, depending on the performance
requirements of future interior floor coverings.
t�
Project No. 105 9 76-10 Page 16 July 8, 2005
I
Recommendations are traditionally included with geotechnical foundation recommendations or
' sand layers placed below slabs and above/below vapor barriers and retarders for the purpose of
protecting the barrier /retarder and to assist in concrete curing. Sand layer requirements are the
purview of the foundation engineer /structural engineer, and should be provided in accordance
' with ACI Publication 302 "Guide for Concrete Floor and Slab Construction ". We have provided
recommendations in Table 1 that we consider to be a minimum from a geotechnical perspective.
These recommendations must be confirmed (and/or altered) by the foundation engineer, based
upon the performance expectations of the foundation. Ultimately, the design of the moisture
retarder system and recommendations for concrete placement and curing are the purview of the
' foundation engineer, in consideration of the project requirements provided by the architect and
developer.
' Garage floor slabs should be 4 inches thick and should be reinforced in a similar manner as
living area floor slabs. Garage floor slabs should also be placed separately from adjacent wall
footings with a positive separation maintained with % -inch minimum felt expansion joint
' materials and quartered with weakened plane joints. A 12 -inch wide grade beam founded at the
same depth as adjacent footings should be provided across garage entrances. The grade beam
should be reinforced with a minimum of two (2) No. 4 bars, one (1) top and one (1) bottom.
' Prior to placing concrete, the subgrade soils below all floor slabs should be pre - watered to
achieve a moisture content that is at least equal or slightly greater than optimum moisture
content. This moisture content should penetrate to a minimum depth of 12 inches into the
subgrade soils.
' 6.6.3 Medium Expansion Potential (Expansion Index of 51 to 90)
Onsite soils may exhibit a MEDIUM expansion potential as classified in accordance with Table 18 -I -B
' of the 1997 Uniform Building Code (UBC). The 1997 UBC specifies that slab on ground foundations
(floor slabs) resting on soils with expansion indices greater than 20, require special design
considerations in accordance with 1997 UBC Section 1815. The design procedures outlined in 1997
' UBC Section 1815 are based on the thickness and plasticity index of each different soil type existing
within the upper 15 feet of the building site. For final design purposes we have assumed an effective
plasticity index of 20 in accordance with 1997 UBC Section 1815.4.2.
6.6.3.1 Footines
' Exterior continuous footings for both one- and two -story construction should be founded at a
minimum depth of 18 inches below lowest adjacent final grade. Interior continuous footings for
both one- and two -story construction may be founded at a minimum depth of 12 inches below
the lowest adjacent grade. All continuous footings should have a minimum width of 12 and 15
inches, for one -story and two -story buildings, respectively, and should be reinforced with two (2)
No. 4 bars, one (1) top and one (1) bottom.
I• Exterior pad footings intended for the support of roof overhangs, such as second story decks,
patio covers and similar construction should be a minimum of 24 inches square and founded at a
' minimum depth of 18 inches below the lowest adjacent final grade. The pad footings should be
reinforced with No. 4 bars spaced a maximum of 18 inches on centers, both ways, near the
bottom -third of the footings.
� �qr
IProject No. 105976-10 Page 17 July 8, 2005
6 6.3.2 Building Floor Slabs
The project architect or structural engineer should evaluate minimum floor slab thickness and
reinforcement in accordance with 1997 UBC Section 1815 based on an effective plasticity index
of 20. Unless a more stringent design is recommended by the architect or the structural engineer,
we recommend a minimum slab thickness of 4 inches for living area slabs, and be reinforced
' with No. 3 bars spaced a maximum of 18 inches on centers, both ways. All slab reinforcement
should be supported on concrete chairs or bricks to ensure the desired placement near mid -depth.
Interior floor slabs with moisture sensitive floor coverings should be underlain by a 15 -mil thick
moisture /retarder to help reduce the upward migration of moisture from the underlying subgrade
soils. The moisture /vapor barrier product used should meet the performance standards of an
' ASTM E 1745 Class A material, and be properly installed in accordance with ACI publication
302. It is the responsibility of the contractor to ensure that the moisture /vapor barrier systems are
placed in accordance with the project plans and specifications, and that the moisture /vapor
' retarder materials are free of tears and punctures prior to concrete placement. Additional
moisture reduction and/or prevention measures may be needed, depending on the performance
requirements of future interior floor coverings.
' Recommendations are traditionally included with geotechnical foundation recommendations or
sand layers placed below slabs and above/below vapor barriers and retarders for the purpose of
' protecting the barrier /retarder and to assist in concrete curing. Sand layer requirements are the
purview of the foundation engineer /structural engineer, and should be provided in accordance
with ACI Publication 302 "Guide for Concrete Floor and Slab Construction ". We have provided
recommendations in Table 1 that we consider to be a minimum from a geotechnical perspective.
These recommendations must be confirmed (and/or altered) by the foundation engineer, based
upon the performance expectations of the foundation. Ultimately, the design of the moisture
' retarder system and recommendations for concrete placement and curing are the purview of the
foundation engineer, in consideration of the project requirements provided by the architect and
developer.
Garage area floor slabs should be 5 inches thick and should be reinforced in a similar manner as
concrete floor slabs. Garage area floor slabs should also be placed separately from adjacent wall
' footings with a positive separation maintained with % -inch minimum felt expansion joint
materials and quartered with weakened plane joints. A 12 -inch wide grade beam founded at the
same depth as adjacent footings should be provided across garage entrances. The grade beam
' should be reinforced with a minimum of two (2) No. 4 bars, one (1) top and one (1) bottom.
' Prior to placing concrete, the subgrade soils below all floor slabs should be pre - watered to
achieve a moisture content that is 5 percent greater than optimum moisture content. This
moisture content should penetrate to a minimum depth of 18 inches into the subgrade soils.
0
IProject No. 1059 76-10 Page 18 July 8, 2005
6.7 Post Tensioned Slab /Foundation Design Recommendations
In lieu of the proceeding recommendations for conventional footing and floor slabs, post tensioned slabs
may be utilized for the support of the proposed structures. We recommend that the foundation engineer
design the foundation system using the geotechnical parameters provided below in Table 1. These
' parameters have been determined in general accordance with Chapter 18 Section 1816 of the Uniform
Building Code (UBC), 1997 edition. Alternate designs are allowed per 1997 UBC Section 1806.2 that
addresses the effects of expansive soils when present. In utilizing these parameters, the foundation
' engineer should design the foundation system in accordance with the allowable deflection criteria of
applicable codes and the requirements of the structural engineer /architect.
' Please note that the post tensioned design methodology reflected in UBC Chapter 18 is in part based on
the assumption that soil moisture changes around and beneath the post - tensioned slabs are influenced
only by climatological conditions. Soil moisture change below slabs is the major factor in foundation
damages relating to expansive soil. The UBC design methodology has no consideration for
presaturation, owner irrigation, or other nonclimate'related influences on the moisture content of
subgrade soils. In recognition of these factors, we have modified the geotechnical parameters obtained
-, from this methodology to account for reasonable irrigation practices and proper homeowner
maintenance. In addition, we recommend that prior to foundation construction, slab subgrades be
presoaked to 12 inches prior to trenching and maintained at above optimum moisture up to concrete
' construction. We further recommend that the moisture content of the soil around the immediate
perimeter of the slab be maintained near optimum moisture content (or above) during construction and
up to occupancy.
1 The following geotechnical parameters provided in Table 1 assume that if the areas adjacent to the
foundation are planted and irrigated, these areas will be designed with proper drainage so ponding,
' which causes significant moisture change below the foundation, does not occur. Our recommendations
do not account for excessive irrigation and/or incorrect landscape design. Sunken planters placed
adjacent to the foundation, should either be designed with an efficient drainage system or liners to
prevent moisture infiltration below the foundation. Some lifting of the perimeter foundation beam
should be expected even with properly constructed planters. Based on the design parameters we have
provided, and our experience with monitoring similar sites on these types of soils, we anticipate that if
' the soils become saturated below the perimeter of the foundations due to incorrect landscaping irrigation
or maintenance, then up to approximately' /< -inch of uplift could occur at the perimeter of the foundation
' relative to the central portion of the slab.
Future owners should be informed and educated regarding the importance of maintaining a consistent
' level of soil moisture. The owners should be made aware of the potential negative consequences of both
excessive watering, as well as allowing expansive soils to become too dry. The soil will undergo
shrinkage as it dries up, followed by swelling during the rainy winter season, or when irrigation is
' resumed. This will result in distress to site improvements and structures.
1
1 2%
IProject No. 105 9 76 -1 0 Page 19 July 8, 2005
TABLE 1:
Preliminarp Geotechnical Parameters for Post Tensioned Foundation Slab Design
• The above sand and moisture retarder barrier recommendations are traditionally included with geotechnical foundation
recommendations although they are generally not a major factor influencing the geotechnical performance of the foundation.
The sand and moisture retarder barrier requirements are the purview of the foundation engineer /corrosion engineer and the
builder to ensure that the concrete cures correctly is protected from corrosive environments and moisture penetration of the
floor is acceptable to the future owners. Therefore, the above recommendations may be superceded by the requirements of
the previously mentioned parties.
' 68 Corrosivitp to Concrete and Metal
' The National Association of Corrosion Engineers (MACE) defines corrosion as "a deterioration of a
substance or its properties because of a reaction with its environment." From a geotechnical viewpoint,
the "environment" is the prevailing foundation soils and the "substances" are the reinforced concrete
' foundations.
' Project No. 105976-10 Page 20 July 8, 2005
Expansion Index
Very Low
Low
Medium
Percent that is Finer than 0 mm in the
< 20 percent (assumed)
< 20 percent (assumed)
< 30 percent (assumed)
Fraction Passing the No. 200 Sieve.
Clay Mineral Type
Montmorillonite (assumed)
Montmorillonite assumed
Montmorillonite (assumed)
Thomthwaite Moisture Index
-20
-20
-20
Depth to Constant Soil Suction (estimated as
the depth to constant moisture content over
7 feet
7 feet
7 feet
time, but within UBC limits)
Constant Soil Suction
P.F. 3.6
P.F. 3.6
P.F. 3.6
Moisture Velocity
0.7 inches/month
0.7 inches /month
0.7 inches/month
Center Lift Edge moisture
variation distance, a
5.5 feet
5.5 feet
5.5 feet
Center lift, y,
1.5 inches
2.0 inches
2.5 inches
Edge Lift Edge moisture variation
2.5 feet
3.0 feet
3.5 feet
distance, e�
Edge lift, y.
0.4 inches
0.8 inches
1.0 inches
Soluble Sulfate Content for Design of
Concrete Mixtures in Contact with Site Soils
Negligible
Negligible
Negligible
in Accordance with 1997 UBC Table 19 -A-4
Modulus of Subgrade Reaction, k (assuming
200lbs /in'
200lbs /in'
120lbs/in'
resaturation as indicated below)
Minimum Perimeter Foundation Embedment
12
18
24
Rebar in Exterior Footing
-
-
-
Sand and Visqueen Type l Type 1 Type 2
Additional Recommendations:
1. Presoak to 12 inches prior to trenching, maintain at above optimum up to concrete construction
Sand & Visqueen
Type 1
Install a 15 -mil moisture retarder barrier covered by a minimum of 1 -inch layer of sand. Note: The builder must ensure that the
Visqueen has been lapped and sealed and not punctured as a result of being placed in direct contact with the native soils or by other
construction methods.
Type 2
a 15 -mil moisture retarder barrier covered by a minimum of 1 -inch layer of sand and 2 inches below. Or , install a 15 -mil
'Install
moisture retarder barrier in contact with the native soils an dcovered by a minimum of at least 2 inches of sand. Note: For both options,
the builder must ensure that the Visqueen has been lapped and sealed and not punctured as a result of being placed in direct contact with
the native soils or by other construction methods.
• The above sand and moisture retarder barrier recommendations are traditionally included with geotechnical foundation
recommendations although they are generally not a major factor influencing the geotechnical performance of the foundation.
The sand and moisture retarder barrier requirements are the purview of the foundation engineer /corrosion engineer and the
builder to ensure that the concrete cures correctly is protected from corrosive environments and moisture penetration of the
floor is acceptable to the future owners. Therefore, the above recommendations may be superceded by the requirements of
the previously mentioned parties.
' 68 Corrosivitp to Concrete and Metal
' The National Association of Corrosion Engineers (MACE) defines corrosion as "a deterioration of a
substance or its properties because of a reaction with its environment." From a geotechnical viewpoint,
the "environment" is the prevailing foundation soils and the "substances" are the reinforced concrete
' foundations.
' Project No. 105976-10 Page 20 July 8, 2005
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 the U.B.C., 1997, provides specific
guidelines for the concrete mix design when the soluble sulfate content of the soils exceeds 0.1 percent
by weight.
Based on testing performed within the project area, the onsite soils are classified as having a negligible
sulfate exposure condition in accordance with Table 19 -A -4, of U.B.C., 1997. Therefore, in accordance
with Table 19 -A -4 structural concrete in contact with earth materials should have cement of Type I or 11.
' This recommendation is based on limited samples of the subsurface soils. The initiation of grading at
the site could blend various soil types and import soils may be used locally. These changes made to the
foundation soils could alter sulfate content levels. Accordingly, it is recommended that additional
testing be performed at the completion of grading to verify sulfate contents and other chemical
properties.
Despite the minimum recommendation above, LGC is not a corrosion engineer, therefore, we
recommend that you consult with a competent corrosion engineer and conduct additional testing (if
required) to evaluate the actual corrosion potential of the site and provide recommendations to mitigate
the corrosion potential with respect to the proposed improvements. The recommendations of the
corrosion engineer may supercede the above requirements.
6.9 Structural Setbacks
Structural setbacks, in addition to those required per the UBC, are not required due to geologic or
geotechnical conditions within the site. Building setbacks from slopes, property lines, etc. should
conform to 1997 UBC requirements.
' 7.0 RETAINING WALLS
7.1 Active and At -Rest Earth Pressures
An active earth pressure represented by an equivalent fluid having a density of 40 pounds per cubic foot
(pcf) should tentatively be used for design of cantilevered walls up to 10 feet high retaining a drained
level backfill. Where the wall backfill slopes upward at 2:1 (h:v), the above value should be increased
to 63 pcf. All retaining walls should be designed to resist any surcharge loads imposed by other nearby
walls or structures in addition to the above active earth pressures.
' For design of retaining walls that are restrained at the top, an at -rest earth pressure equivalent to a fluid
having a density of 60 pcf should tentatively be used for walls up to 10 feet high supporting a level
backfill. This value should be increased to 95 pcf for ascending 2:1 (h:v) backfill. All retaining walls
should be designed to resist any surcharge loads imposed by other nearby walls or structures in addition
to the above at -rest earth pressures.
I
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23
' Project No. 105976 -10 Page 21 July 8, 2005
7.2 Drainage
' "Weep holes or open vertical masonry joints should be provided in retaining walls to prevent entrapment
of water in the backfill. Weep holes, if used, should be 3 inches in minimum diameter and provided at
minimum intervals of 6 feet along the wall. Open vertical masonry joints, if used, should be provided at
32 -inch minimum intervals. A continuous gravel fill, 12 inches by 12 inches, should be placed behind
the weep holes or open masonry joints. The gravel should be wrapped in filter fabric to prevent
infiltration of fines and subsequent clogging of the gravel. Filter fabric may consist of Mirafi 140N or
equivalent.
In lieu of weep holes or open joints, a perforated pipe and gravel subdrain may be used. Perforated pipe
should consist of 4 -inch minimum diameter PVC Schedule 40 or ABS SDR -35, with the perforations
laid down. The pipe should be embedded in 1' /z cubic feet per foot of /4- or l Y2 -inch open graded gavel
wrapped in filter fabric. Filter fabric may consist of Mirafi 140N or equivalent.
The backfilled side of the retaining wall supporting backfill should be coated with an approved
waterproofing compound to inhibit infiltration of moisture through the walls.
1
73 Temporary Excavations
All excavations should be made in accordance with OSHA requirements. LGC is not responsible for job
site safety.
7.4 Wall Backrll
Retaining -wall backfill materials should be approved by the soils engineer prior to placement. All
retaining -wall backfill should be placed in 6- to 8 -inch maximum lifts, watered or air dried as necessary
to achieve near optimum moisture conditions and compacted in place to a minimum relative compaction
of 90 percent.
8.0 CONCRETE FLATWORK
8.1 Thickness and Joint Spacing
To reduce the potential of unsightly cracking, concrete sidewalks and patio type slabs should be at least
I3%Z inches thick and provided with construction or expansion joints every 6 feet or less. Any concrete
driveway slabs should be at least 4 inches thick and provided with construction or expansion joints every
10 feet or less.
[1
I
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1 Project No. 105976 -10 Page 22 July 8, 2005
I
8 2 Subarade Preparation
As a further measure to minimize cracking of concrete flatwork, the subgrade soils underlying concrete
flatwork should first be compacted to a minimum relative compaction of 90 percent and then thoroughly
wetted to achieve a moisture content that is at least equal to or slightly greater than optimum moisture
content. This moisture should extend to a depth of 12 inches below subgrade and be maintained in the
soils during the placement of concrete. Pre - watering of the soils will promote uniform curing of the
concrete and minimize the development of shrinkage cracks. A representative of the project
geotechnical engineer should observe and verify the density and moisture content of the soils and the
depth of moisture penetration prior to placing concrete.
' 9.0 PRELIMINARYASPHALTIC CONCRETE PAVEMENT DESIGN
A representative sample of soil was tested. The laboratory test results indicated an R -value of 11.
Assumed Traffic Indicies are presented in the table below. This table shows our minimum
recommended street sections. Further evaluation should be carried out once grading is complete, and
j R- values have been confirmed. The following asphaltic concrete pavement sections have been
computed in accordance with the State of California design procedures. These and alternative asphaltic
concrete pavement calculations are attached in Appendix E.
Subgrade soil immediately below the aggregate base (base) should be compacted to a minimum of 95
percent relative compaction based on ASTM Test Method D1557 to a minimum depth of 12 inches.
Final subgrade compaction should be performed prior to placing base or asphaltic concrete and after all
utility trench backfills have been compacted and tested.
Base materials should consist of Class 2 aggregate base conforming to Section 26 -1.02B of the State of
California Standard Specifications or crushed aggregate base conforming to Section 200 -2 of the
Standard Specifications for Public Works Construction (Greenbook). Base materials should be
compacted to a minimum of 95 percent relative compaction based on ASTM Test Method D1557. The
base materials should be at or slightly below optimum moisture content when compacted. Asphaltic
concrete materials and construction should conform to Section 203 of the Greenbook.
I
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IProject No. 105976-10 Page 23 July 8, 2005
Assumed Traffic Index
5.0 1
67
7.0
Design R -value
11 I
11
I1
AC Thickness
0.30 feet
0.30 feet
0.35 feet
'
AB Thickness
0.65 feet
1.00 feet
1.25 feet
Notes: AC — Asphaltic Concrete (feet)
AB — Aggregate Base (feet)
Subgrade soil immediately below the aggregate base (base) should be compacted to a minimum of 95
percent relative compaction based on ASTM Test Method D1557 to a minimum depth of 12 inches.
Final subgrade compaction should be performed prior to placing base or asphaltic concrete and after all
utility trench backfills have been compacted and tested.
Base materials should consist of Class 2 aggregate base conforming to Section 26 -1.02B of the State of
California Standard Specifications or crushed aggregate base conforming to Section 200 -2 of the
Standard Specifications for Public Works Construction (Greenbook). Base materials should be
compacted to a minimum of 95 percent relative compaction based on ASTM Test Method D1557. The
base materials should be at or slightly below optimum moisture content when compacted. Asphaltic
concrete materials and construction should conform to Section 203 of the Greenbook.
I
I z6
IProject No. 105976-10 Page 23 July 8, 2005
I
' 10.0 SLOPE STABILITYANALYSIS
10.1 "Potential Deep Seated Failures
The factor of safety of the proposed 2:1(h:v) cut and fill slopes up to 65 and 50 feet respectively, are
anticipated to meet the minimum acceptable factor of safety for gross stability for static loading and
pseudostatic loading. The laboratory testing and slope stability analyses required to evaluate the
proposed slopes is beyond the scope of this project, but can be performed upon your request. In
addition, these analyses may have already been performed and submitted to the County of Riverside.
1 10.2 Potential Surficial Failures
1 To evaluate the stability of the near surface soils, the factor of safety with regard to surficial failure can
be calculated. To perform this calculation, the geotechnical engineering properties of the near surface
soils, including unit weight and shear strength characteristics, are assigned. The surficial stability of the
slope face can be calculated using an infinite slope with seepage occurring parallel to the slope face. In
the analysis, the vertical depth of the soil saturation is taken as a minimum of 4 feet. Per local code
requirements, the minimum acceptable factor of safety for surficial stability is 1.5 for static loading. If
the calculations mentioned above were performed, it is our opinion that the compacted fill slopes would
be surficially stable.
For cut slopes, the surficial soils are removed when the cut slopes are constructed therefore the parallel
seepage model for calculating surficial stability is not applicable to cut slopes. As a result of the
surficial materials being removed, the potential for surficial failure to occur in this manner on a cut slope
is very remote.
1 11.0 GRADING PLAN REVIEWAND CONSTRUCTION SERVICES
This report has been prepared for the exclusive use of CENTEX HOMES to assist the project engineer and
architect in the design of the proposed development. It is recommended that LGC be engaged to review the
final design drawings and specifications prior to construction. This is to verify that the recommendations
contained in this report have been properly interpreted and are incorporated into the project specifications. If
LGC is not accorded the opportunity to review these documents, we can take no responsibility for
misinterpretation of our recommendations.
We recommend that LGC be retained to provide geotechnical engineering services during construction of the
excavation and foundation phases of the work. This is to observe compliance with the design, specifications or
recommendations and to allow design changes in the event that the subsurface conditions differ from those
anticipated prior to the start of construction.
If the project plans change significantly (e.g., building loads or type of structures), we should be retained to
review our original design recommendations and their applicability to the revised construction. If conditions
are encountered during the construction operations that appear to be different than those indicated in this report,
this office should be notified immediately. Design and construction revisions may be required.
1 -2�1
IProject No. 105976 -10 Page 24 July 8, 2005
11.0 I N VE S T I G A T IO N L I W TA T IO NS
Our services were performed using the degree of care and skill ordinarily exercised, under similar
circumstances, by reputable soils engineers and geologists practicing in this or similar localities. No other
warranty, expressed or implied, is made as to the conclusions and professional advice included in this report.
This report is based on data obtained from limited observations of the site, which have been extrapolated to
characterize the site. While the scope of services performed is considered suitable to adequately characterize the
site geotechnical conditions relative to the proposed development, no practical investigation can completely
eliminate uncertainty regarding the anticipated geotechnical conditions in connection with a subject site.
Variations may exist and conditions not observed or described in this report may be encountered during
construction.
This report is issued with the understanding that it is the responsibility of the owner, or of his/her representative,
to ensure that the information and recommendations contained herein are brought to the attention of the other
consultants and incorporated into the plans. The contractor should properly implement the recommendations
during construction and notify the owner if they consider any of the recommendations presented herein to be
unsafe, or unsuitable.
The findings of this report are valid as of the present date. However, changes in the conditions of a site can and
do occur with the passage of time, whether they be due to natural processes or the works of man on this or
1 adjacent properties. The findings, conclusions, and recommendations presented in this report can be relied upon
only if LGC has the opportunity to observe the subsurface conditions during grading and construction of the
project, in order to confirm that our preliminary findings are representative for the site. This report is intended
exclusively for use by the client, any use of or reliance on this report by a third party shall be at such party's
sole risk.
'In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or
the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by
changes outside our control. Therefore, this report is subject to review and modification.
iThe opportunity to be of service is appreciated. Should you have any questions regarding the content of this
report, or should you require additional information, please do not hesitate to contact this office at your earliest
convenience.
Respectfully submitted,
LGC INLAND, INC.
I
Stephen M. Poole
Vice President
Principal Engineer, GE 692
CW /SMP /ts
Chad E. Welke
Associate Geologist/Engineer, CEG 2378, RCE 63712
?11
1 Project No. 105976-10 Page 25 July 8, 2005
I
1
Aerial Photo¢ranh Interpretation Table
IProject No. 1059 76-10 Page 2 July 8, 2005
••
20-12,20-14
•��
�• •��
� • / •
111
11 1 • �
1�1 1•
111
IProject No. 1059 76-10 Page 2 July 8, 2005
ty Project Name: CENTEX TRACT 23064 -4 Logged by: AS LOG OF TEST PIT 5
Project Number. 105976 -10 Elevation: Engineering Properties
Equipment: CASE 580 Location /Grid: SEE GEOTECHNICAL MAP Dry
USCS sample Moisture Density
Depth Date: 6 -10 -05 Description: eeUniiDle No. (PO)
0 -14' I A Very Old Axial Channel Deposits:
Silty SAND; reddish brown, medium dense, slightly moist, 3 -6" cobbles
with some gravel.
GRAPHICAL REPRESENTATION: NORTH WALL I SCALE: 1" = 5'
Qvoa I SM
SURFACE SLOPE: LEVEL
TREND: N 20'W
i
i
TOTAL DEPTH= 14.0 FEET
NO GROUNDWATER
iENCOUNTERED
0
Project Name: CENTEX TRACT 23064.4
Logged by: AS
LOG OF TEST PIT 4
Project Number. 105876 -10
Elevation:
Engineering Properties
Equipment: CASE 580
Location /Grid: SEE GEOTECHNICAL MAP
D
Dry
USCS
Sample
No.
Moisture
(%)
Depth
Date: 6 -10 -05
Description:
Geologic
(pet)
(pet)
0 -5'
A Pauba Formation:
Op
DC 1 @ 7'
14.9
113.8
Silty SANDSTONE; yellowish tan, slightly moist, moderately soft to
moderately hard, fine sand.
5 -11'
B Clayey SANDSTONE; medium brown, moist, moderately hard, fine sand.
GRAPHICAL REPRESENTATION: NORTH WALL
SCALE: V = 5'
SURFACE SLOPE: LEVEL
TREND: N 30' W
.._ - _
\1 A
i 1 I I f1
I
- --
rl
TOTAL DEPTH= 11.0 FEET
B
1 ,
NO GROUNDWATER
I
----- - -------
(ENCOUNTERED
LGC
I ! I
i I I
I INLAND
0
Project Name: CENTEX TRACT 23064.4
Logged by: AS
LOG OF TEST PIT 3
Project Number. 105976 -10
Elevation:
Engineering Properties
Equipment: CASE 580
Location /Grid: SEE GEOTECHNICAL MAP
Dry
U$CS
Sample
N °'
Moisture
1 %1
Density
Depth
Date: 6 -10 -05
Description:
o uniaie
(Pat)
0-6'
A Very Old Axial Channel Deposits:
Qvoa
SC
Bag 1 @ 2'
Silty SAND; reddish brown, medium dense, slightly moist, 3 -6" cobbles
DC 1 @ 2'
10.3
111.1
with some gravel.
6 -10'
B Pauba Formation:
Op
DC 2 @ 7'
5.9
98.4
Silty SANDSTONE; yellowish tan, slightly moist, moderately soft, few
small 2 -3" stones, fine sand.
GRAPHICAL REPRESENTATION: NORTH WALL
SCALE: 1" = 5'
SURFACE SLOPE: LEVEL
TREND: N 40- W
I
i I
�
I
A
I i I I
:
TOTAL DEPTH= 10.0 FEET
NO GROUNDWATER
B I
(ENCOUNTERED
--- ------ -
I
LGC
INLAND
Project Name: CENTEX TRACT 23064 -4 Logged by: AS LOG OF TEST PIT 2
Project Number. 105976 -10 Elevation: Engineering Properties
Equipment: CASE 580 Location /Grid: SEE GEOTECHNICAL MAP Dry
USCS Sample Molature Density
Depth Date: 6 -10-05 Description: oeU lglo No. (x1 Ipon
0 -1' A Topsoil:
Silty SAND; grayish brown, dry, loose, numerous rootlets, very porous.
1 -12' B Very Old Axial Channel Deposits:
Clayey SAND; reddish brown, slightly moist, medium dense, fine to
coarse sand, few 4 -6" cobbles.
GRAPHICAL REPRESENTATION: NORTH WALL I SCALE: 1" = 5'
SM
Qvoa I SC I DC 1 @ 3' 1 9.1 1 110.1
SURFACE SLOPE: LEVEL I TREND: W
TOTAL DEPTH= 12.0 FEET
j NO GROUNDWATER
ENCOUNTERED
_,
Project Name: CENTEX TRACT 230644 Logged by: AS
LOG OF TEST PIT 1
Project Number: 105976 -10
Elevation:
Engineering Properties
Equipment: CASE 580
Location /Grid: SEE GEOTECHNICAL MAP
USCS
Sample
Moisture
Density
Depth
Date: 6 -10-05
Description:
Geologic
No.
(pon
unit nit
0 -12'
A Very Old Axial Channel Deposits:
Qvoa
SM
Bag 1 @ 3'
Silty SAND; reddish brown, medium dense, slightly moist, 3 -6" cobbles
with some gravel.
GRAPHICAL REPRESENTATION: NORTH WALL
SCALE: 1° = 5'
SURFACE SLOPE: LEVEL
TREND: N 30' W
I
! !
-
--
! A
____ .
� -- _._. =- -
i
�
_ . __ -- ( -TOTAL
!
DEPTH= 12.0 FEET
NO GROUNDWATER
t i
!ENCOUNTERED
i
!
LG C
NI
I LAND
_,
' APPENDIX C
Laboratory Testing Procedures and Test Results
' The laboratory testing program was directed towards providing quantitative data relating to the relevant
engineering properties of the soils. Samples considered representative of site conditions were tested in general
1 accordance with American Society for Testing and Materials (ASTM) procedure and/or California Test Methods
(CTM), where applicable. The following summary is a brief outline of the test type and a table summarizing the
test results.
Soil Classification: Soils were classified in general accordance with ASTM Test Methods D2487 and D2488.
This system utilizes the Atterberg limits and grain size distribution of a soil. The soil classifications (or group
symbol) are shown on the laboratory test data, boring logs, and trench logs.
I
I
LI
I
1
fl
ll
Expansion Index. The expansion potential of selected samples were evaluated by the Expansion Index Test
ASTM D4829. Specimens are molded under a given cwmpactive 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
'k :y SAMPLE F
COMPAC-TEDbk -.
EXPANSION
ESPANSION ,
..t+ --- �' •. -3,
ors :.�
t '` DESCRIPTION
DENSITY c =i..
?,, w^INDEX'1„ '
._
*
,,�LOGATION-`
,
,
�wPO7�NT�L ,
TP -3 @ 2 feet
Clayey Sand
107.6
20
VERY LOW
* Per Table 18 -1 -B of 1997 UBC.
Moisture and Density Determination Tests: Moisture content (ASTM D2216) and dry density determinations
(ASTM D2937) were performed on relatively undisturbed samples obtained from the test borings and/or trenches.
The results of these tests are presented in the boring and/or trench logs. Where applicable, only moisture content
was determined from undisturbed or disturbed samples.
Maximum Density Tests: The maximum dry density and optimum moisture content of typical materials were
determined in accordance with ASTM D1557. The results of these tests are presented in the table below:
SAMPLE` �s
r LOCATION, .w
z SAMPLE
. , 5 r,DESCRIPTIONs ".
MAXI1lfU4DRYx".'
: DENSITi';(PSfl. _
, OPTIM(7 —. O— -
,z „ rCONTENT'(°�J
TP -3 @ 2 feet
Reddish bSrowdn, Clayey
124.5
11.0
i&
I
I
I
I
I I
I
I
I I
I
I
lJ
I
R-Value. The resistance R-value was determined by the ASTM D2844 soils. The sample(s) were prepared and
exudation pressure and R-value were determined. These/This result(s) were used for asphaltic concrete pavement
design purposes.
D&CAM71
TP-3 @ 2 feet Clayey Sand
Soluble Sulfates, The soluble sulfate contents of selected sample(s) were determined by standard geochemical
methods (CTM 417). The soluble sulfate content is used to determine the appropriate cement type and maximum
water-cement ratios. The test results are presented in the table below:
-" Z
'SULFATE
ZVE
& ,
�, , %
L0CA770Ng M
c
* Based on the 1997 edition of the Uniform Building Code (U.B. C.), Table No. 19-A-4, prepared by the International
Conference of Building Officials (ICBO, 1997).
IProject No. 1059 76-10 Page 2 July 8, 2005
t
1100
1000
KIM
800
YI X
.col
Mf
400
300
200
100
L
-100
-400 -300 -200 -100
CALIFORNIA FAULT MAP
Centex -TR 23064
0 100 200 300 400 500 600
3(o
TEST.OUT
* *
* U B C S E I S
' * version 1.03
* *
* * * * * * * * * * * ** * * * * * * * * **
' COMPUTATION OF 1997
UNIFORM BUILDING CODE
SEISMIC DESIGN PARAMETERS
JOB NUMBER: 105976 -10 DATE: 06 -30 -2005
JOB NAME: Centex -TR 23064
FAULT- DATA -FILE NAME: CDMGUBCR.DAT
SITE COORDINATES:
SITE LATITUDE: 33.4619
SITE LONGITUDE: 117.0830
' UBC SEISMIC ZONE: 0.4
UBC SOIL PROFILE TYPE: SO
'
NEAREST TYPE
A FAULT:
NAME: ELSINORE-
JULIAN
DISTANCE:
11.5 km
'
NEAREST TYPE
B FAULT:
NAME: ELSINORE
- TEMECULA
DISTANCE:
0.1 km
NEAREST TYPE
C FAULT:
NAME:
DISTANCE:
99999.0 km
SELECTED UBC
SEISMIC COEFFICIENTS:
Na: 1.3
Nv: 1.6
Ca: 0.57
Cv: 1.02
'
Ts: 0.716
To: 0.143
* CAUTION:
The digitized data points used to model faults are
*
limited in number and have been digitized from small-
*
scale maps (e.g., 1:750,000 scale). Consequently,
*
the estimated fault- site - distances may be in error by
'
*
several kilometers. Therefore, it is important that
*
the distances be carefully checked for accuracy and
*
adjusted as needed, before they are used in design.
**ir ir*k*ie it ie
a}*+ s+ s it irAir*rt**it it it's *ir it it it ie ie ir's *' sir *ir*te irA****ir ir*ir it it it it it's ie*ir4 it it it ir*'s
' Page 1
%'I
1
' TEST.OUT
1
L
L
1
I
11
IJ
1
1
---------------------------
SUMMARY OF FAULT PARAMETERS
---------------------------
--------------------------------------------------------------
ABBREVIATED
FAULT NAME
ELSINORE - TEMECULA
ELSINORE- JULIAN
ELSINORE -GLEN IVY
SAN JACINTO -ANZA
SAN JACINTO -SAN JACINTO VALLEY
NEWPORT - INGLEWOOD (offshore)
ROSE CANYON
SAN JACINTO- COYOTE CREEK
EARTHQUAKE VALLEY
CHINO- CENTRAL AVE. (Elsinore)
SAN JACINTO -SAN BERNARDINO
SAN ANDREAS - Southern
ELSINORE - WHITTIER
CORONADO BANK
PINTO MOUNTAIN
NEWPORT - INGLEWOOD (L.A.Basin)
PALOS VERDES
BURNT MTN.
CUCAMONGA
ELSINORE- COYOTE MOUNTAIN
SAN JACINTO - BORREGO
NORTH FRONTAL FAULT ZONE (West)
EUREKA PEAK
NORTH FRONTAL FAULT ZONE (East)
SAN JOSE
CLEGHORN
SIERRA MADRE (Central)
LANDERS
HELENDALE - S. LOCKHARDT
SAN ANDREAS - 1857 Rupture
LENWOOD - LOCKHART -OLD WOMAN SPRGS
CLAMSHELL - SAWPIT
JOHNSON VALLEY (Northern)
EMERSON 50. - COPPER MTN.
RAYMOND
SUPERSTITION MTN. (San Jacinto)
ELMORE RANCH
VERDUGO
PISGAH- BULLION MTN.- MESQUITE LK
CALICO - HIDALGO
SUPERSTITION HILLS (San Jacinto)
BRAWLEY SEISMIC ZONE
HOLLYWOOD
ELSINORE - LAGUNA SALADA
SANTA MONICA
SIERRA MADRE (San Fernando)
APPROX.
DISTANCE
(km)
2.4
11.5
31.8
33.6
34.5
46.3
48.7
53.3
56.0
60.6
63.4
63.5
67.4
73.9
74.2
79.5
81.7
84.8
86.7
86.8
87.5
88.5
89.3
91.0
91.7
91.8
95.5
99.5
103.0
103.1
107.5
111.8
112.0
113.2
116.0
119.7
123.7
124.1
124.4
125.4
125.8
128.3
129.1
138.3
140.9
144.4
SOURCE
TYPE
(A, B, C)
Page 2
MAX.
MAG.
(MW)
6.8
7.1
6.8
7.2
6.9
6.9
6.9
6.8
6.5
6.7
6.7
7.4
6.8
7.4
7.0
6.9
7.1
6.5
7.0
6.8
6.6
7.0
6.5
6.7
6.5
6.5
7.0
7.3
7.1
7.8
7.3
6.5
6.7
6.9
6.5
6.6
6.6
6.7
7.1
7.1
6.6
6.5
6.5
7.0
6.6
6.7
SLIP
RATE
(mm /yr)
5.00
5.00
5.00
12.00
12.00
1.50
1.50
4.00
2.00
1.00
12.00
24.00
2.50
3.00
2.50
1.00
3.00
0.60
5.00
4.00
4.00
1.00
0.60
0.50
0.50
3.00
3.00
0.60
0.60
34.00
0.60
0.50
0.60
0.60
0.50
5.00
1.00
0.50
0.60
0.60
4.00
25.00
1.00
3.50
1.00
2.00
FAULT
TYPE
(SS, DS, BT)
SS
SS
SS
SS
SS
SS
SS
SS
SS
DS
SS
SS
SS
SS
SS
SS
SS
SS
DS
SS
SS
DS
55
DS
DS
SS
DS
SS
SS
S5
55
DS
SS
SS
DS
SS
55
DS
SS
SS
SS
SS
DS
55
DS
DS
369
1
TEST.OUT
SUMMARY
OF FAULT
PARAMETERS
---------------------------
-------------------------------------------------------------------------------
I
APPROX.ISOURCE
I
MAX. I
SLIP I
FAULT
'
ABBREVIATED IDISTANCEI
TYPE I
MAG. I
RATE I
TYPE
FAULT NAME I
(km) I(A,B,C)I
(MW) I
(mm /yr) I(SS,DS,BT)
SAN GABRIEL I
146.3 I
B I
7.0 I
1.00 I
SS
MALIBU COAST 1
148.6 I
B I
6.7 I
0.30 I
DS
IMPERIAL I
153.0 I
A 1
7.0 I
20.00 I
SS
GRAVEL HILLS - HARPER LAKE I
157.6 I
B I
6.9 I
0.60 I
55
ANACAPA -DUME I
160.4
I B I
7.3 I
3.00 I
DS
'
SANTA SUSANA I
162.3
I B I
6.6 I
5.00 I
DS
HOLSER I
171.3
I B I
6.5 I
0.40 I
DS
BLACKWATER I
173.8
I B I
6.9 I
0.60 I
SS
OAK RIDGE (onshore)
182.3
I B I
6.9 I
4.00 I
DS
'
SIMI -SANTA ROSA
183.8
I B I
6.7 I
1.00 I
DS
SAN CAYETANO
189.7
I B I
6.8 1
6.00 I
DS
SANTA YNEZ (East)
208.9
I B I
7.0 I
2.00 I
55
GARLOCK (West)
214.0
I A I
7.1
I 6.00
I ss
VENTURA - PITAS POINT
1
1 214.7
I B
6.8 I
1.00
I DS
GARLOCK (East)
( 220.6
I A
I 7.3 I
7.00
I SS
M.RIDGE- ARROYO PARIDA -SANTA ANA
( 223.4
I B
I 6.7
I 0.40
I DS
' PLEITO THRUST
RED MOUNTAIN
I 225.9
I 229.0
I B
I B
I 6.8
6.8
I 2.00
1 2.00
I DS
I DS
SANTA CRUZ ISLAND
I 233.1
I B
1 6.8
I 1.00
I DS
BIG PINE
( 233.9
I B
I 6.7
1 0.80
I 55
OWL LAKE
PANAMINT VALLEY
I 239.2
1 239.6
I B
B
I 6.5
1 7.2
I 2.00
I 2.50
I 55
1 55
WHITE WOLF
I 240.7
B
I 7.2
I 2.00
I DS
TANK CANYON
I 242.9
B
I 6.5
I 1.00
I DS
' So. SIERRA NEVADA
LITTLE LAKE
1 243.3
1 244.6
B
B
1 7.1
I 6.7
I 0.10
I 0.70
I DS
I SS
DEATH VALLEY (South)
1 245.9
I B
I 6.9
I 4.00
I SS
SANTA YNEZ (West)
I 262.5
I B
I 6.9
I 2.00
I SS
SANTA ROSA ISLAND
I 269.3
I B
I 6.9
I 1.00
I DS
' DEATH VALLEY (Graben)
I 289.5
I B
I 6.9
I 4.00
I DS
LOS ALAMOS -W. BASELINE
I 305.6
I B
I 6.8
I 0.70
I DS
OWENS VALLEY
I 314.7
I B
I 7.6
I 1.50
I 55
LIONS HEAD
I 323.1
I B
I 6.6
I 0.02
I DS
SAN JUAN
I 326.2
I B
1 7.0
I 1.00
1 ss
'
SAN LUIS RANGE (S. Margin)
330.8
I B
I 7.0
I 0.20
I DS
HUNTER MTN. - SALINE VALLEY
1 336.9
I B
I 7.0
I 2.50
1 ss
CASMALIA (OrCUtt Frontal Fault)
I 340.3
I B
I 6.5
I 0.25
I DS
DEATH VALLEY (Northern)
I 343.6
I A
I 7.2
I 5.00
I SS
INDEPENDENCE
I 350.7
I B
I 6.9
I 0.20
I DS
LOS OSOS
I 360.1
I B
I 6.8
I 0.50
I DS
HOSGRI
I 369.3
I B
I 7.3
I 2.50
I 55
RINCONADA
I 378.3
I B
I 7.3
I 1.00
I SS
'
BIRCH CREEK
I 407.6
I B
1 6.5
1 0.70
1 DS
WHITE MOUNTAINS
I 411.1
I B
I 7.1
I 1.00
I SS
DEEP SPRINGS
I 428.7
I B
I 6.6
I 0.80
1 DS
' SAN ANDREAS (Creeping)
I 428.8
I B
I 5.0
I 34.00
I 55
' Page 3
1
4
i
iTEST.OUT
SUMMARY
OF FAULT
PARAMETERS
---------------------------
i -------------------------------------------------------------------------------
I
APPROX.ISOURCE
I
MAX. I
SLIP I
FAULT
IDISTANCEI
ABBREVIATED---
TYPE 1
MAW. I
RATE I
TYPE
FAULT NAME I
i
(km) I(A,B,C)I
(Mw) I
(mm /y r) I(SS,DS,BT)
- - - - - - -- - - - - --
DEATH VALLEY (N. of Cucamongo) I
431.7 I
A
7.0 I
5.00 I
SS
ROUND VALLEY (E. of S.N.Mtns.) I
443.9 (
B I
6.8 I
1.00 I
DS
FISH SLOUGH I
i
450.3 I
B I
6.6 I
0.20 I
DS
HILTON CREEK I
470.2 I
B I
6.7 I
2.50 I
DS
HARTLEY SPRINGS I
495.3 I
B I
6.6 I
0.50 I
DS
ORTIGALITA I
510.0 I
B I
6.9 I
1.00 I
ss
CALAVERAS (So.of Calaveras Res) I
i
517.7 I
B I
6.2 I
15.00 I
SS
MONTEREY BAY - TULARCITOS I
523.7 I
B I
7.1 I
0.50 I
DS
PALO COLORADO - SUR I
526.9 I
B I
7.0 I
3.00 I
SS
QUIEN SABE I
530.3 I
B I
6.5 I
1.00
SS
MONO LAKE I
i
531.5
B I
6.6 I
2.50
I DS
ZAYANTE- VERGELES I
549.8
I 8 I
6.8 I
0.10
I SS
SARGENT
I 554.6
I B I
6.8 I
3.00
I SS
SAN ANDREAS (1906)
( 555.1
I A I
7.9 I
24.00
I SS
ROBINSON CREEK
1
( 563.0
I B I
6.5 I
0.50
I DS
SAN GREGORIO
I 598.8
I A I
7.3 I
5.00
I SS
GREENVILLE
I 601.7
I B I
6.9 I
2.00
I SS
ANTELOPE VALLEY
I 603.7
I B
6.7
( 0.80
I DS
'
HAYWARD (SE Extension)
I 603.8
I B
I 6.5
I 3.00
I SS
MONTE VISTA - SHANNON
I 604.8
I B
I 6.5
I 0.40
I DS
HAYWARD (Total Length)
I 623.1
I A
I 7.1
1 9.00
1 SS
CALAVERAS (No.of Calaveras Res)
GENOA
I 623.1
I 629.9
I B
I B
I 6.8
I 6.9
I 6.00
I 1.00
I SS
I DS
CONCORD - GREEN VALLEY
I 669.5
I B
I 6.9
I 6.00
I SS
RODGERS CREEK
I 708.8
I A
I 7.0
I 9.00
I SS
' WEST NAPA
POINT REYES
I 709.0
I 730.0
I B
I B
I 6.5
I 6.8
I 1.00
I 0.30
I SS
I DS
HUNTING CREEK - BERRYESSA
I 730.2
I B
I 6.9
I 6.00
SS
MAACAMA (South)
I 770.8
I B
I 6.9
I 9.00
I SS
i COLLAYOMI
BARTLETT SPRINGS
I 786.9
I 789.3
B
A
I 6.5
I 7.1
I 0.60
I 6.00
1 SS
I ss
MAACAMA (Central)
I 812.4
A
I 7.1
I 9.00
I ss
MAACAMA (North)
I 871.2
I A
I 7.1
I 9.00
I SS
ROUND VALLEY (N. S.F.Bay)
I 876.0
I B
I 6.8
I 6.00
1 ss
BATTLE CREEK
i
I 893.6
I B
I 6.5
I 0.50
I DS
LAKE MOUNTAIN
934.3
B
6.7
6.00
SS
GARBERVILLE - BRICELAND
1 952.2
1 B
1 6.9
1 9.00
1 ss
MENDOCINO FAULT ZONE
1 1009.4
I A
I 7.4
I 35.00
I DS
LITTLE SALMON (Onshore)
1 1014.4
I A
I 7.0
I 5.00
I DS
MAD RIVER
1 1016.1
I B
I 7.1
I 0.70
I DS
CASCADIA SUBDUCTION ZONE
1 1023.8
1 A
I 8.3
1 35.00
I DS
MCKINLEYVILLE
1 1026.8
I B
I 7.0
I 0.60
I DS
TRINIDAD
1 1028.1
I B
I 7.3
I 2.50
I DS
i FICKLE HILL
1 1028.9
I B
I 6.9
I 0.60
I DS
TABLE BLUFF
1 1035.1
I B
I 7.0
I 0.60
I DS
LITTLE SALMON (offshore)
1 1048.3
I B
I 7.1
I 1.00
I DS
---------------------------
SUMMARY
OF FAULT
PARAMETERS
i
Page
4
i Ap
1
1
TEST.OUT
--------------------------------- ------- ----- - - - --- -
APPROX.ISOURCE I
- - ---------------------
MAX. I
SLIP
I FAULT
ABBREVIATED IDISTANCEI TYPE I
MAG. I
RATE
I TYPE
FAULT NAME I (km) I(A,B,C)l
(Mw) I
(mm /yr)
I(SS,DS,BT)
BIG LAGOON BALD MTN.FLT.ZONE j 1064.6 B
7.3
0.50
DS
rtrtrtrtrt'.rrtrtrtrtrtrtrtrtrtrtrtrtrtrtrtrtrtrtrtrtrtt rtrt# � AAir it it i'irrtRrtArtAirArtrtbrtrtrthrtrtrtrt',e irrtrtrtrt rtirrtrtrtrtrtrtrtrtrtrtrtrtrt
Page 5
a�
7RrITJ7NT"PfRTbn vms.'AC'CEL'EMaT16iS
CAMP. & BOZ. (1997 Rev.) AL 1
10000
Cn
L
0
a) 1000
C
L
NW
N
100
0.00 0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (q)
1
1
PROBABILITY OF EXCEEDANCE
CAMP. & BOZ. (1997 Rev.) AL 1
25 yrs 50 yrs
� 0
100
a
80
a
70
-0 60
° 50
ru
40
Cu
c
30
x
20
w
ILI
x
0.00 0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (q)
mkT1TJ7NrnrRr0n 7
SADIGH ET AL. (1997) DEEP SOIL 1
10000
1000
0
L
W
100
$ 0.00 0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (q)
1
1
1
PROBABILITY OF EXCEEDANCE
SADIGH ET AL. (1997) DEEP SOIL 1
0
25 yrs 50 yrs
� 0
100
.E
80
ON
0
70
-0 60
° 50
n
40
c
30
a)
x 20
w
iG
0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (q)
2
r RETURN PERIOD
vs.mA"LT1rkT1al\
ABRAHAMSON & SILVA (1997) SOIL 1
10000
L
1000
0
n u
L
•V
100
0.00 0.25 0.50 0.75 1.00 1.25 1.50
-it Acceleration (q)
1
1
0
NO
0
Cu
0
^L
^A
W
m
0
X
W
PROBABILITY OF EXCEEDANCE
ABRAHAMSON & SILVA (1997) SOIL 1
0
25 yrs 50 yrs
F 0
100
a
0
70
.f
50
M
30
20
10
x
0.00 0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (q)
1
1
1
PAVING DESIGN
JN:
105976-10
CONSULT:
CW
CLIENT
Centex -TR 23064 -4
CALCULATION SHEET #
1
CALTRANS METHOD FOR DESIGN OF FLEXIBLE PAVEMENT
Input "R" value or "CBR" of native soil
11
Type of Index Property - "R" value or "CBR"
(C or R)
R
R Value
R Value used for Caltrans Method
11
Input Traffic Index (TI)
5
Calculated Total Gravel Equivalent (GE)
1.424
feet
Calculated Total Gravel Equivalent (GE)
17.088
inches
Calculated Gravel Factor (Gf) for A/C paving
2.53
Gravel Factor for Base Course (Gf)
1.0
TRIAL EQUIVALENT PAVEMENT SECTIONS:
A/C SECTION
BASE SECTION
FEET
Section Gravel Equivalent
Minimum
A/C Section
Minimum
Thickness GE GE
Delta
Base
Thickness
Base
inches feet inches
inches
inches
feet
feet
3 0.63 7.60
9.48
9.6
0.25
0.80
3.6 0.76 9.13
7.96
7.8
0.30
0.65
4.2 0.89 10.65
6.44
6.6
0.35
0.55
4.8 1.01 12.17
4.92
4.8
0.40
0.40
5.4 1.14 13.69
3.40
3.6
0.45
0.30
6 1.27 15.21
1.88
1.8
0.50
0.15
6.6 1.39 16.73
0.36
0.6
0.55
0.05
7 1.48 17.74
-0.66
#VALUE!
0.58
#VALUE!
8 1.69 20.28
-3.19
#VALUE!
0.67
#VALUE!
9 1.90 22.81
-5.72
#VALUE!
0.75
#VALUE!
10 2.11 25.35
-8.26
#VALUE!
0.83
#VALUE!
1
0
PAVING DESIGN
JN:
106976 -10
CONSULT:
CW
CLIENT
Centex -TR 23064 -4
CALCULATION SHEET #
2
CALTRANS METHOD FOR DESIGN OF FLEXIBLE PAVEMENT
Input "R" value or "CBR" of native soil
11
Type of Index Property - "R" value or "CBR"
(C or R)
R
R Value
R Value used for Caltrans Method
11
Input Traffic Index (TI)
6
Calculated Total Gravel Equivalent (GE)
1.7088
feet
Calculated Total Gravel Equivalent (GE)
20.5056
inches
Calculated Gravel Factor (Gf) for A/C paving
2.31
Gravel Factor for Base Course (Gf)
1.0
TRIAL EQUIVALENT PAVEMENT SECTIONS:
A/C SECTION
BASE SECTION
FEET
Section Gravel Equivalent
Minimum
A/C Section
Minimum
Thickness GE GE
Delta
Base
Thickness
Base
inches feet inches
inches
inches
feet
feet
3 0.58 6.94
13.56
13.8
0.25
1.15
3.6 0.69 8.33
12.18
12.0
0.30
1.00
4.2 0.81 9.72
10.79
10.8
0.35
0.90
4.8 0.93 11.11
9.40
9.6
0.40
0.80
5.4 1.04 12.50
8.01
7.8
0.45
0.65
6 1.16 13.88
6.62
6.6
0.50
0.55
6.6 1.27 15.27
5.23
5.4
0.55
0.45
7 1.35 16.20
4.31
4.2
0.58
0.35
8 1.54 18.51
1.99
1.8
0.67
0.15
9 1.74 20.83
10 1.93 23.14
-0.32
-2.63
#VALUE!
#VALUE!
0.75
0.83
#VALUE!
#VALUE!
0
1
1
PAVING DESIGN
JN:
105976 -10
CONSULT: CW
CLIENT
Centex -TR 23064 -4
CALCULATION SHEET #
3
CALTRANS METHOD FOR DESIGN OF FLEXIBLE PAVEMENT
Input "R" value or "CBR" of native soil
11
Type of Index Property - "R" value or "CBR"
(C or R)
R
R Value
R Value used for Caltrans Method
11
Input Traffic Index (TI)
7
Calculated Total Gravel Equivalent (GE)
1.9936
feet
Calculated Total Gravel Equivalent (GE)
23.9232
inches
Calculated Gravel Factor (Gf) for A/C paving
2.14
Gravel Factor for Base Course (Gf)
1.0
TRIAL EQUIVALENT PAVEMENT SECTIONS:
A/C SECTION
BASE SECTION
FEET
Section Gravel Equivalent
Minimum
A/C Section Minimum
Thickness GE GE
Delta
Base
Thickness
Base
inches feet inches
inches
inches
feet
feet
3 0.54 6.43
17.50
17.4
0.25
1.45
3.6 0.64 7.71
16.21
16.2
0.30
1.35
4.2 0.75 9.00
14.93
15.0
0.35
1.25
4.8 0.86 10.28
13.64
13.8
0.40
1.15
5.4 0.96 11.57
12.35
12.6
0.45
1.05
6 1.07 12.85
11.07
10.8
0.50
0.90
6.6 1.18 14.14
9.78
9.6
0.55
0.80
7 1.25 15.00
8.93
9.0
0.58
0.75
8 1.43 17.14
9 1.61 19.28
10 1.79 21.42
6.79
4.64
2.50
6.6
4.8
2.4
0.67
0.75
1 0.83
0.55
0.40
0.20
' LGCrnLAND, INC
General Earthwork and Grading Specifications
' 1.0 General
' 1.1 Intent: These General Earthwork 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 earthwork 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 a qualified Geotechnical Consultant of Record (Geotechnical Consultant). The
Geotechnical Consultant 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 of the 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 observation, mapping, and compaction testing.
' During the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and
document the subsurface exposures to verify the geotecbnical design assumptions. If the observed
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 observed conditions, and notify the review agency where required.
' The Geotechnical Consultant shall observe the moisture - conditioning and processing of the
' subgrade and fill materials and perform relative compaction testing of fill to confirm that the
attained level of compaction is being accomplished as specified. 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 Earthwork 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 project plans and specifications. The Contractor shall prepare and submit to
the owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork
grading, the number of "equipment' of work and the estimated quantities of daily earthwork
contemplated for the site prior to commencement of grading. The Contractor shall inform the
owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan
at least 24 hours in advance of such changes so that appropriate personnel will be available for
observation and testing. The Contractor shall not assume that the Geotechnical Consultant is
aware of all grading operations.
15k
1
' The Contractor shall have the sole responsibility to provide adequate equipment and methods to
accomplish the earthwork 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. It is the contractor's sole responsibility to
provide proper fill compaction.
20 Preparation ofAreas to be Filled
'21 Clearing and Grubbing: Vegetation, such as brush, grass, roots, and other deleterious material
shall be sufficiently removed and properly disposed of in a method acceptable to the owner,
' governing agencies, and the Geotechnical Consultant.
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 10 percent of organic matter. Nesting of the organic
materials shall not be allowed.
' If potentially hazardous materials are encountered, the Contractor shall stop work in the affected
area, and a hazardous material specialist shall be informed immediately for proper evaluation and
' handling of these materials prior to continuing to work in that area.
As presently defined by the State of California, 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 these fluids onto the ground may
constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed. The
contractor is responsible for all hazardous waste relating to his work. The Geotechnical Consultant
does not have expertise in this area. If hazardous waste is a concern, then the Client should acquire
' the services of a qualified environmental assessor.
2.2 Processing: 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 oversize material and the working surface is
' reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction.
23 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 otherwise unsuitable ground shall be overexcavated to competent ground as evaluated
by the Geotechnical Consultant during grading.
S�
Project No. 105976-10 Page 2 July 8, 2005
I
' 24 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
t 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 flatter than 5:1 shall
' also be benched or otherwise 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
prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor
shall obtain a written acceptance from the Geotechnical Consultant prior to fill placement. A
' licensed surveyor shall provide the survey control for determining elevations of processed areas,
keys, and benches.
' 3.0 Fill Material
1 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 shall 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 performed.
' 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 uniformity of material and moisture throughout
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' Project No. 105976-10 Page 3 July 8, 2005
' 4.2 Fill Moisture Conditioning: Fill soils shall be watered, dried back, blended, and/or mixed, as
necessary to attain a relatively uniform moisture content at or slightly 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 D1557 -91).
4.3 Compaction of Fill: After each layer has been moisture - conditioned, mixed, and evenly spread, it
' shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test
Method D1557 -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 uniformity.
4.4 Compaction of Fill Slopes: In addition to normal 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 Testing. Field tests for moisture content and relative compaction of the fill soils shall
be performed 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 (1) 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
1 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 surveyor to assure that sufficient grade stakes are established so that the Geotechnical
Consultant can determine the test locations with sufficient accuracy. At a minimum, two (2) grade
stakes within a 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 the 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.
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Project No. 105976-10
Page 4
July 8, 2005
' 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 determined 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 the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to
placement of materials for construction of the fill portion of the slope, unless otherwise recommended by
' the Geotechnical Consultant.
' ZO
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
1
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 of
the 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 observed by the Geotechnical Consultant.
'
7.4
The Geotechnical Consultant shall test the trench backfill for relative compaction. At least one (1)
test should be made for every 300 feet of trench and 2 feet of fill.
'
7.5
Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of
Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant
'
that the fill lift can be compacted to the minimum relative compaction by his alternative equipment
and method.
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1 Project No. 105976-10 Page 5 July 8, 2005
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