HomeMy WebLinkAboutVOL_3_Appendix D
Appendices
Appendix D Geotechnical
General Plan Update and Associated SPecific Plans ElR
The Pianninx Center
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Appendices
This Page Left Intentionally Blank.
General Plan Update and AJJociated Specific Plans EIR
The Planning Cemel'
.JAMES R. EVANS, CEG 974
2926 HARRIS DRIVE
VISTA, CALIFORNIA, 92084
760-758-3176
March &, 2005
Soils Southwest. Inl;
Subject: Extension of Geologie Mapping to the Golf Course Area & Proposed
Development
Gentlemen:
Based on proposed development plans recently supplied to us, we have extended OUI'
geologic mapping to those area as well as the mountain slopes above these areas. We
have also changed color schemes and in some cases symbols to clarify geologic units
covered by the Q.riginal geologic map. As was the method for the original mapping, where
there was no reason to change the map based on our observations, the mapped areas were
Wlchanged for this map although the scale was changed from 1 "=: 2000' to 1''"'" 1 000' .
Most of the changes involved addition of areas which in our experience represent
landslides either ancient or recent. No attempt at this time was made to refine th.e age or
hazard potential of these features.
As can be seen from the Geologic Map, there are many landslides along the sidewalls
of the canyon or perched along the sides oftbe ravines entering the canyon. Some of the
proposed residential or structural development takes advantage of the more gentle slopes
resulting from the landslides to provide level building areas. Other locations are not
located on older slides but are located close to or at the base of ravines having slides
perched upstream of them.
On additional conclusion must be made:
A) The proposed leveled structural pad. areas will have to be carefully evaluated to
detennine whether these locations can be rendered safe and stable without
potentially affecting offsite improvements. This will require much more detailed
investigation and evaluation.
The geologic mapping represents surface observations and does not imply that additional
investigation may not discover conditions no found based or\. these observations.
VE~~r RUL Y YOURS r) ~~~-
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~rAMES R. BV ANS, CEO 974
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SOilS SOUTHWEST, INC.
SOILS, MATERIALS AND ENVIRONMENTAL ENGINEERING CONSULTANTS
897 VIA lATA, SUITE N ~ COLTON, CA 92324 . (909) 370-0474 .. (909) 370-0481 9 FAX (909) 370~3156
Feasibility Study
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Proposed Mixed-Use Development
Arrowhead Springs
City of San Bernardino
California
Project No. 05027-F1
February 14, 2005
Prepared for:
Transtech
624 Brea Canyon Road
Walnut, California 91789
Estab1iR;81984
SOILS SOUTHWEST, INC.
SOilS, MATERIALS AND ENVIRONMENTAL ENGINEERING CONSULTANTS
Feb8r9u7aVryIAfA:A.S.ugE N ~ COLTON, CA 92324 ~ (909) 370-0474 $ (909) 370-0481 .. FAX (909) 370-3156
4. LUO Project No 05027 -F1
Transtech
624 8rea Canyon Road
Walnut, California 91789
Attention
Mr A.li Cayir
Subject:
Feasibility Study/Report of Preliminary Geotechnlcai Evaluations
Proposed Mixed-Use Development
Arrowhead Springs
City of San Bernardino, California
Reference:
Development Layout plan by American Development
Gentlemen:
Presented herewith is the Feasibility Study Report of the Geotechnical Evaluations conducted
for the 500+/-acre site of the proposed mixed-use development to be located in Arrowhead
Springs area of the City of San Bernardino, California.
Based on the results of geological and getechnical cursory visits and preliminary investigations
completed at this time, it is our opinion that the proposed areas of planned developments should
be considered suitable from geotechnical and geologic viewpoint. No landslide, subsidence,
unstable slopes etc. are apparent. However, with the proximity of A-P Special studies zone
nearby, supplemental geologic trenching etc. should be required and the tentative
recommendations supplied should be verified following site-specific grading plan review_
Hillside in nature with numerous canyons and ridges, extensive site preparations and grading
are expected. The soils encountered primarily consist of silty gravelly sand of decomposed
granitic origin, or deeply weathered or decomposed or highly fractured bedrock. No unstable
slopes with outdipping bedding Most of the grading should be accomplished using heavy duty
construction equipment. No blasting and/or jack-hammering should be anticipated. Supplemental
geotechnical and geological explorations, however, are recommended prior to actual grading and
construction.
Based on analyses and evaluations completed at this time, it is our opinion that, from geolical
and geotechnical viewpoint, the subject development should be feasible with no apparent major
adverse soils and/or geologic constraint.
distl5-addressee
Roy White
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PROPOSED DEVELOPMENT
ARROWHEAD SPRINGS
SAN BERNARDINO, CA
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Arrowhead Springs/San Bernardino
OS027-F1
1.0 Introduction
This report presents the results of Preliminary Soils and Foundation Evaluations conducted for
the proposed Arrowhead Springs mixed-used development to be located within Arrowhead
Springs area of San Bernardino, California. With the hillside in nature with numerous canyons
and ridges, extensive site preparations and grading, should be expected
The purpose of this evaluation is to tentativeiy determine the nature and engineering properties
of the near grade and subsuiiace soils/bedrock, and to provide preliminary geotechnical and
geological recommendations pertaining to construction af numerous structural pads, proposed
cut and fill slopes, site grading, tentative foundation design. concrete slab..on-grade, paving and
inspection during construction.
The geotechnical evaluations included geologic observations and limited soils sampling from the
existing numerous exposed side-slopes, laboratory testing, engineering analyses and the
preparation of this report. Following grading plan review, however, supplemental oils and
geologic trenching, exploratory borings, soils sampling etc. should be warranted.
The recommendations contained reflect our best estimate of the soils/bedrock conditions as
currently being exposed. It may not to be considered as a warranty for the soils and bedrock
conditions that may be existing encompassing the entire project site area.
1.1 Site Descriptions
Hilly in nature with sharp terrain, valleys and inaccessible steep slopes, the subject property is
located within San Bernardino mountains, off Highway 18, City of San Bernardino In general,
the site consists of numerous canyons primarily facing south I with anticipated thick deposits of
alluviums within adjacent canyon bottoms. While most of the planned pads areas should be
somewhat accessible using a dozer and a tractor-mounted backhoe, the general project area is
considered accessible to drillrig. Supplemental geologic and geotechnical explorations and
evaluations should be expected following grading plan review, when supplied.sign.
The existing slope gradients are estimated to vary anywhere from approximately 1: 1 to 2: 1
(horizontal to vertical) or flatter. Presence of minor surficial slopewash and/or minor surficial
slides are also apparent.
1.2 Proposed Development
Based on the preliminary development plan supplied, it is understood that the subject property
will be developed to accommodate the following:
o Expansion/addition to the existing historical hotel near the north-east
o Construction of hotel, office complex and residential housing near the north,
o Construction of golf course, primarily along existing canyon bottoms,
o Residential development on the ridge near the south of the historical pond,
o Construction of senior housing and single family dwellings near the south, and
o Construction of access highways and roadways.
The structural details for construction are not available at this time, however, it is expected that
proposed dwellings will be of one or two-story structures of conventional wood frame and stucco
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with concrete slab-on-garde. The office complex etc. is assumed of concrete block or concrete
tilt-up or wood or steel framed conventional construction.
For this type of construction, relatively light loads will be imposed on the underlying foundation
soils. Associated construction, among others, should include cut and fill slopes, interior streets,
curb-gutter and installation of subsurface utilities. Use of an-site sewage disposal etc, may be
required for private sewage dIsposal system.
For structural pad, extensive site grading is expected to include typical cut, fill or cut/fill transition
conditions. Manufactured slopes with 2:1,1.5:1 or 1:1, may be expected.
Grading requiring major cuts to about 50 feet into ridges and to about 20 feet of hillsides are
expected. Similar massive grading requiring new fill soils placements should be anticipated for
the southern residential development as proposed. Structural setbacks adjacent to the known
A-P zones should be evaluated following supplemental geOlogic trenching and geologic
investigations
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2.0 Scope of Work
Geologic evaluations included monitoring of the existing numerous slope-sidewalls and other
excavations currently exposed in connection with the Inland Feeder project. The preliminary
Geologic Evaluation Report for the site prepared by James Evans, CEG, is attached.
For preliminary geotechnical evaluations, scope of work included soil sampling from the exposed
slopes or exposed cuts currently existing, necessary laboratory testing, engineering analyses and
the preparation of this report. No exploratory test borings are presently included. Exploratory
borings will b e programmed following grading plan review. when supplied.
For the preliminary report prepared herein, the scope of work included the following tasks:
o Review of the geologic report prepared by James Evans, CEG.
o Undisturbed and bulk soil sampling from expose cuts or exposed slopes or from
the existing temporary roadways.
o laboratory testing conducted on selected bulk, undisturbed and on mixed..ot!
samples were programmed according to the project requirements. The laboratory
testing included determinations of:
Maximum Dry Density and Optimum Moisture Content (ASTM 01557),
Soil's Shear Strengths (ASTM 03080),
Consolidation Characteristics (ASTM 02435), and
Expansion Potential, E! (AST!\.~ 04928 & UBC Table 29-2).
Brief descriptions of the test procedures used and the test results are provided
in Appendix B.
o Based on the data of our soil sampling and laboratory testing, engineering
analyses and evaluations were made, on which to base our recommendations
for foundation design, slab-an-grade, site preparations and grading and
inspection during construction.
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3.0 Existing Soil Conditions
3.1 Subsurface Conditions
Within the areas of the upper plateau and ridges near the south as planned for residential
development following 50'+/-cuts, the subgrade soils, in general, is expected of moderately
dense, deeply weathered gravelly sand with some silts considered excavatible using conventional
construction equipment. No outdipping bedding to adjacent slopes or underlying massive bedrock
requiring blasting etc. should be expected within the maximum cuts currently planned
Within the areas of the upper plateau and hillsides near the north proposed for hotel, commercial
and office complex, the subgrades are expected to consist of grayish brown to gray highly
fractures metamorphic rocks, weathered gravelly sand of decomposed granitic origin, and/or
calcite as derived from old hot springs.
Within the areas of the planned addition to the hotel near the northeast, the site soils re expected
of upper gravelly sand, overlying relatively fractured metamorphic bedrock considered
excavatible by using conventional constriction equipment No outdipping bedding should be
associated with the hillside cuts proposed.
Within canyon bottoms, subgrade soils should consist of alluviums of silty fine sand and fine to
medium coarse gravelly sand of variable consistency along with numerous cobbles and isolated
rocks. Typical minor slide debris may be associated with the north-south direction canyons near
the northwest. Subgrade soils underlying the upper described alluviums are expected to consist
of well consolidated gravelly sand or weathered bedrock of siltstone/sandstone origin. Generally
compressible in nature,
Slope surface includes minor slippage along with upper loose silty gravelly sand (top-soils),
overlying moderate Iy dense gravelly sand and/or weathered and fractured bedrock considered
excavatable using conventional heavy-duty construction equipment. While .most of the natural
slopes appear stable with no apparent outdipping bedrock conditions as described in the
geologic report, supplemental verifications on such should be made prior to actual grading and
construction. For localized slope stabilization, if warranted , as determined by the project geologic,
stabilization recommendations on such will be supplied in form of buttress using soil reinforcing.
Again, determinations of which will be made based on supplemental geologic investigations as
required.
Presence of minor landslides comprised of remnants of bedrock of broken sandstone with gravel
deposits are described in the geologic report (attached). The landslides described are related
to localized slumping of weathered bedrock materials.
Free groundwater and presence of numerous hot springs are evidenced generally within upper
elevations of the property. Supplemental shallow depth groundwater is expected within the
southern ares of the project proposed for senior housing and single family dwellings. Considering
hilly nature of the project site, perched groundwater conditions may be expected.
Based on the field and laboratory testing and geologic and geotechnical evaluations, the
following general site-soil characteristics are described;
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In absence of precise grading plan review, the pads planned are expected either fills, or on
grades to be constructed following cuts of the ridges and hillside, or on the pads constructed of
cut/fill transition. Detailed recommendations for structures constructed on such pads will be
supplied prior to actual grading and construction. In general, within valley areas, being
susceptible to consolidation and unequal settlements to footings, the near surface soils existing
at their present state are considered unsuitable for structural support or new structural fill soils
placement For adequate support, such low..lying valley areas should be graded as
recommended herein. In overall, such undesirable site soils are expected to exist in between 3
to 5 feet within the upper ridges and upper plateau, and to about 12 to 18 feet or more within
the canyon bottoms. Actual depth of such loose soil deposits should be determined during
grading and construction.
The results of shea r tests conducted on bulk soil samples procured from exposed slope surface
areas and from ridge top remolded to 90% indicate moderate shear strengths under increased
moisture conditions. Laboratory test results are shown on Appendix B of this report.
Consolidation tests are conducted on representative undisturbed soils sampled at depth and on
remolded bulk soil samples exhibit relatively 'low' compressibility under anticipated structural
loading.
Expansion tests conducted on representative near grade soils exhibit 'very low' expansion
potential with Expansion Index, EI, less than 20. Supplemental evaluations on such should be
made following grading plan review.
Local soils free of organic should be considered suitable for use as structural backfill.
Additional information regarding subsurface conditions may be obtained from the geologic report,
attached.
3.2 Excavatability
Based on the cursory investigations, including exposed road cuts and slope surface, it is our
opinion that grading and excavations required for the project may be accomplished using
conventional heavy-duty construction equipment In absence of shallow-depth bedrock, no
blasting and/or jack-hammering should be anticipated.
3.3 Groundwater
Natural spring water is expected during grading and construction Shallow depth groundwater,
however, should be expected within the southern low-lying areas. As per USGS Bulletin 1898,
groundwater within southern boundary and along the National Forest boundary areas are
expected at about 1 0 feet below grade. Actual groundwater conditions should be verified during
detailed subsurface investigation.
3.4 Subsurface Variations
During grading, buried irrigation, debris, organic and others may be encountered. In addition,
variations in bedrock, their continuity and orientations may be exposed different from those as
described in this and in the geologic report. Detailed geotechnical recommendations on such will
be supplied when requested.
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3.5 Liquefaction
Liquefaction is caused by build up of excess hydrostatic pressure in saturated cohesion less soils
due to cyclic stress generated by ground shaking during an earthquake. The significant factors
on which liquefaction potential of a soil deposit depends, among others include, soil type, relative
soil density, intensity of earthquake, duration of ground shaking, and depth of ground water.
Based on the USGS Bulletin 1898, it is our opinion that the that the low-lying areas near the
south current proposed for residential development, may be susceptible to liquefaction in event
os a strong motion earthquake. Considering hillside nature of the remaining areas underlain by
bedrock, no other liquefiable soils should be anticipated. Detailed evaluations for site soil
liquefaction susceptibility should be performed during subsequent geotechnIcal evaluations.
3.6 Seismic Design Parameters as USe/CBe
The site is situated at about 0.0 km from A-Fault (San Andreas-South), and at about 2 km from
S-Fault (North Frontal Fault Zone~west). Accordingly, for structural design, the following seismic
parameters are suggested based on USC/CBC
UBe Chapter 16 Seismic Design Recommended
Table No. Parameters Value
-
16-1 Seismic Zone Factor, Z 04
..-
16-J Soil Profile Type Sd
-
16-Q Seismic Coefficient, Ca 0.44 N a
16-R Seismic Coefficient, Cv O.64Nv
16-S Near Source Factor, No 1.5
16-T Near Source Factor, Nv 2.0
16-U Seismic Source Type M>/=74
Supplemental seismic design parameters are provided in Appendix C.
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4.0 Preliminary Evaluations and Tentative Recommendations
4.1 General Evaluations
Based on geologic and geotechnical site reconnaissance, limited soils sampling and laboratory
testing completed at this time, it is our opinion that from geotechnical viewpoint. the site should
be considered suitable for the planned development provided supplemental geotechnical and
geologic evaluations are made to verify certain assumptions that are made In preparing this
report. In absence of detailed geologic and geotechnical evaluations, the following tentative
recommendations are supplied for project "overview' only.
With the presence of slope wash, dry alluvium and loose soils existing as observed during site
reconnaissance and limited soils sampling etc., it is our opinion that no structural footings,
concrete slabs or paving should be installed directly bearing on the surface soils presently
existing.
For adequate support, subgrade preparations should include subexcavation of the upper dry and
loose gravelly sandy soils, and their replacement as engineered fill compacted to uniform higher
density as described in the following sections.
Site preparations and grading should be performed in accordance with Appendix Chapter 33 of
the current UBC a nd as per the general applicable grading recommendations as provided
Section 5 of this report.
4.2 Preparations for Structural Pads (general)
No detailed development and grading plan is available at this time for review. Consequently. the
tentative recommendations presented in the following sections should be used for pre-planning
purpose, and should not be used for design and construction.
being hillside in nature, it is expected that site grading requiring cut, fill and/or cut-fill transition
conditions will be associated with the building pads planned. Considering the upper existing
fractured bedrock 0 r unconsolidated to- soils or loose canyon alluviums, it is recommended that
no structural footings, paving or new fill soils placements shall be allowed bearing directly on the
near surface solis existing. Additionally, in order to minimize potential differential settlements to
footings, no transition conditions should be allowed underneath footings and slabs straddling
over cut and fill su bgrades. For adequate structural support, the following tentative general
recommendations are supplied:
A> For the residential units proposed following 50'+/- cuts of the central ridge described earlier,
subject to grading plan review, it is recommended that, following the required terraced cuts to
proposed grades, the cut surface exposing moderately dense subgrades should be further
subexcavated to de pth as required either to, (i) expose the underlying damp to moist, dense and
non-porous natural subgrades, or (ii) to minimum 5 feet below cut-pad grade, or (iii) to the
minimum vertical depth equal to the planned footing embedment + 24-inch, whichever is greateL
Following the cuts described, the site grading should also include 6-inch scarification,
moisturizations to 3 to 5 percent over the soil's Optimum Moisture Content, and recompaction
prior to the excavated local soil replacement as engineered fill compacted to 90%. Cut pads
which may expose shear zones or faults at finish grades should be overexcavated to a minimum
depth of 4 feet and such replaced with engineered fills of local soils compacted to minimum 90%.
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B> Within the low-lying areas requiring fill soils for finish grades. following removal of the upper
loose alluviums or fractured rock debris and upper soft soil deposits as required to expose the
underlying moist and dense subgrades, the surface exposed should be further scarified, moisture
conditioned as described earlier, and recompacted prior to the new engineered fill placement to
the proposed pad grade compacted to minimum 90%.
In order to minimize excessive potential differential settlements to footings and concrete slabs".
on-grade, it is recommended that the overall engineered fills placed with the planned building
pads and 10 feet beyond should be at least 5 feet in thickness. Consequently, within the areas
requiring lesser fills, it is recommended that such areas exposed following site clearance should
be further overexcavated so as to maintain the overall recommended 5 feet ttlick compacted soil
mat below pad finish grades. The fills placed should be in 6 to 8-inch in compacted layers,
placed at near optimum moisture conditions.
Within canyon bottoms requiring engineered fills for planned grade, it is recommended that such
should be placed following removal of alll005e soils so as to expose the underlying firm terrace
deposits or bedrock material. Based on field investigation, it is our opinion that such removal
within canyon bottoms may vary vertically from 12 to 18 feet or more. Actual removal depths
should be determined during grading and construction. All alluvium removals and removals for
fill placement adjacent to natural slope areas and within active drainage courses will require field
review and documentation by the project geologist.
Approved canyon bottoms will require subdrains recommendations on such will be supplied
following grading plan review.
For the fills placed within a canyon bottom and against an adjacent upslope steeper than 5: 1
(horizonta! to vertical), horizontal keys and vertical benches should be excavated into the slope
area. Keying and benching should be sufficient so as to provide at least 6 feet wide benches and
a minimum 4 feet of vertical bench height within firm natural ground, firm bedrock, or engineered
compacted fill. Typical keying and benching details are described in Appendix C.
D> For the areas of the planned office, hotel and commercial development as proposed on near
plateau hillside near the north underlain by desiccated and highly fractured bedrock, following
cuts to planned grades, the subgrades and bedrock exposed should be further subexcavated to
minimum 5 feet, followed by their replacement as engineered fill compacted to minimum 95%.
Fill soils placement against adjacent uphill leading to canyon should be incorporated with at least
equipment with "key" established into underlying bedrock as approved by soils engineer and
project geologist. Supplemental "benching" should be requred during new fill soils placement
against the uphill. With the possible presence of traces of earthquake faults (A-P Zone) along
the current fire access road, adequate structural and grading set-back should be established as
recommended by the project geologist following supplemental geologic study.
E> Within cutlfill transition pads, if any, it is recommended that within areas requiring cuts,
following cuts to planned grade, such portion of the pad should be further subexcavated to depth
equal to 1/2 the maximum depth that will be required within the areas of fills, or to the depth so
as to maintain an overall minimum 5-foot thick compacted fill blanket below footings, whichever
is greater. Schematic descriptions for transition pad construction are provided in Appendix C.
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F> Within liquefaction susceptible areas near the south proposed for residential construction,
subgrade preparations, in general, should consist of minimum 5 feet subexcavations below
proposed finish pad grades, followed by their replacement as engineered fills reinforced with
geogrid, or other similar reinforcing materials. Structured planned within liquefiable soils areas
should be Gonstructed of post-tension load bearing slabs as opposed to convention construction.
being with A-P zones, building setback within southern areas should be determined by the
project geologist fo !lowing detailed geologic investigation requiring trenching. etc.
4,3 Slope Construction
FILL SLOPES:
Fill slopes, if any, planned in association with structural pads srlould be constructed at a gradient
no steeper than 2: 1 (horizontal to vertical). Fill slopes placed within canyon bottom or against
existing uphill steeper than 5 :1 (horizontal to vertical), will require keys and benching as
described earlier.
For the fill slopes planned over existing uphill with 'favorable' bedding conditions, should consist
of at least 15 feet wide 'key' sloping inward with minimum 2% inclination and established at least
3 feet into approved dense sailor firm bedrock as shown in Appendix C.
Fill slopes planned should also consist of 'parallel to slope' subdrains, typically consisting of 4-
inch diameter perforated pvc pipes, encased within 2 eft. of crushed rock or gravel per foot
length of the pipe, wrapped within commercially available filter fabric. Pipes such described
should be placed at mid-height of the constructed slopes, or at a vertical not exceeding 30 feet
in vertical intervals as required by the UBC/CBC. In addition, installation of 4-inch diameter pvc
non-perforated outlet at 100 feet maximum horizontal intervals, should also be considered with
2% sloping and discharging to approved intermediate swale drains.
Structures built in close proximity to a slope should be setback as per the current UBC
requirements. A min imum 10 feet setback is recommended measuring horizontally from the outer
face of foundations to slope-daylight. Further, in order to minimize slope surface erosion, it is
recommended that the slope surface should be grid-rolled or such be over-built and trimmed so
as to expose the underlying compacted inner surface. Use of adequate ground-covering in form
of planting deep-rooted draught resistant vegetation, is suggested. During construction,
continuous inspections by project soils engineer and project engineering geologist, is
recommended. Supplemental information for slope construction is provided in Appendix C.
CUT SLOPE WITH FAVORABLE BEDDING:
Based on the observed soil shear strength parameters for site soils as procured from the
exposed slope surface as described earlier, for a Factor of Safety of 1.5, provided no out-dipping
bedding conditions are exposed, for initial planning purposes, the following tentative maximum
cut and fill slopes may be considered.
Slope Gradient Tentative Maximum Slope Heights. ft.
2:1 40
1.5: 1 20
1:1 12
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The above slope heights described should be verified following supplemental geological and
geotechnical investigations.
Cut and ill slopes constructed should be associated with intermediate benching and swale drains
as required by the current UBC. Supplemental installation of slope surface covering as described
earlier, should be considered in order to minimize slope surrace erosion. During construction,
continuous monitoring by project geologist should be arranged in order to identify out-dipping
bedding conditions, if any, Although no expected, in the event out-dipping bedding is exposed
during the cut for the slopes described, slope stabilization will be required. Recommendations
for such stabilization wil! be supplied during grading.
CUT SLOPES WITH BUTTRESS STABllIZATJON
Following supplemental geologic evaluations, where adverse out-dipping bedding conditions are
exposed, it is our opinion that the portions of the natural slopes commencing at the 'critical plane'
day-light should be stabilized by using 'buttress', Detailed recommendations on supplied
following supplemental geologic and geotechnicl evaluations.
403.1 Structural F ii II Materials
Local soils free of organic, debris and rocks larger than 8-inch in diameter, should be considered
suitable for use as structural backfill.
4.4 Tentative Fou ndation Recommendations
Since greater fills are generally associated with larger settlements, it is our opinion that post-
tension construction should be considered for structural pads with engineered fills 10 feet and
more. Within lesser non-expansive structural fill soils areas, conventional foundations may be
considered. The following presents tentative foundation recommendations that may be
considered for the various structures proposed, subject to subgrade soils verifications following
subsequent detailed geotechnical investigations.
A> For residential construction as proposed within the central ridge areas or within areas where
soils are considered non-susceptible to earthquake induced liquefaction, conventional spread
footings may be designed based on an allowable soil vertical bearing capacity of 1800 psf. If
normal code requirements are applied, the above capacity may further be increased by an
additional 1/3 for sh ort duration of loading which includes the effect of wind and seismic forces.
Considering the non-expansive local soils as encountered, from geotechnical view point, the
conventional spread footings may be sized to 12"x12" for 1-story and 15"x18" for 2-story
construction. Larger footing dimensions may be required if such are recommended by the project
structural engineer. Structural design should conform to the 1997 UBe Seismic Design
requirement criteria as described in Section 3.6 of this repOrt_
From geotechnical view point, footing reinforcements consisting of 2-#4 rebar placed near the
top and 2-#4 rebar near bottom of continuous footings are recommended. Additional
reinforcements if specified by project structural engineer should be incorporated during
constructio n.
The settlements of properly designed and constructed conventional or other alternative
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foundation systems as recommended earlier, supported exclusively into engineered fills of local
soils or its equivalent or better, and carrying the maximum anticipated structural loadings, are
expected to be with in tolerable limits. Estimated total and differential settlements are about 1 and
1 /2-inch, respectively.
B> For the planned commercial/office/hotel complex planned near the north, spread footings may
be designed based on the following equations:
Load bering footings should be established exclusively into compacted fills comprised of local
silty sandy soils or its equivalent or better. Conventional footings established into compacted fills
of local soils free of organic may be designed based on the following equations
Supplemental recommendations, including footing setback, etc. will be supplied following grading
plan review.
Continuous Footings
Square Footings:
q::: 650 + lOOd + 280b, and
q:: 850 + 700d + 220b; where
q :: allowable soil vertical bearing capacity, in psf,
d ::: footing depth in ft., recommended min. 2 ft. below grade,
b::: smallest footing width in ft., recommended min 1.5 ft
C> Residential Structures with Post-Tensioned Foundations
For the residential development proposed within areas of possible liquefiable soils existing near the
southern low-lying areas described earlier, post-tension load bearing concrete slab-an-grade is suggested.
Presented below are the preliminary design parameters that may be implemented by the project structural
engineer when post-tension slab/foundation systems are utilized based on Section 1816 and 1817 of the
1997 use.lt will be tne responsibility of the post-tension slab designer to select the appropriate design
methodology and properly designed foundation system for the soil conditions indicated herein. The slab
designer should provide deflection potential to the architect and/or to structural engineer for incorporation
into structural design. Assuming EI<20, post-tension systems may be designed with the following tentative
parameters subject to verifications following detailed geotechnical evaluations
Tentative Post-Tension Design Parameters
Thornwaite Index -20
Depth of Constant suction 7 ft.
Clay Type Montmorillonite
Clay portion maximum 30%
So iI Suction, pF 3.5
Approx. Moisture Velocity * 0.7 in.lmonth
Avg. Edge Moistu re Variation Distance, em (ft) Center Lift ::; 5.3
Edge Lift::; 2.9
Anticipated Swell, Yen (inch) Center Lift =1.72
Edge Lift::; 0.194
Minimum Slab Thickness (inch) 0
-.
Minimum Footing Depth (inch) 24
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Structural design should conform to the 1997 use Seismic Design requirements as described
in Section 3.6 of this report
It should be noted that variations in subgrade moisture may significantly affect soil volume
change which may directly influence slab-on-grade performance. As stated in the UBe, the Post-
Tensioning Institute procedure is applicable ".. only in those cases where site conditions have
been corrected so that soil moisture conditions area controlled by the climate alone".
Accordingly, it is suggested that post-construction subsurface moisture conditions within the
vicinity of the structure should be controlled by restricting irrigation water and/or any other
efficient surface drainage, etc.
Should the project structural engineer determine that more stringent design criteria are required,
those criteria should supersede the design parameters supplied. Following are the supplemental
recommendations as provided in conjunction with the post-tension construction recommended:
a. Unless otherwise specified, load bearing perimeter edge bemas for both one and two-story
construction should be founded at a minimum depth of 24-inch below the lowest adjacent final
grade
b Recommended minimum slab-an-grade thickness is 6-inch, actual thickness, 11Owever, should be
determined by the project structural engineer.
c. Prior to concrete pour, subgrade soils to receive concrete slab-an-grade should be moistened to
achIeve at least the soil Optimum moisture conditions. Premoistening, if used, will promote
uniform curIng and minimize potential for shrinkage cracks.
c. Use of vapor barrier, such as commercially available 6-mil thick plastic sheeting or its equivalent
or better, is suggested underneath concrete slab-on-grade planned to receive Vinyl, tile or marble
flooring. It should be noted that use of vapor barrier shall not prevent 'dampness' near the top and
bottom of concrete slab-an-grade. Accordingly, supplemental use of 'vapor retarder' should be
considered within areas expected to use tiles and/or vinyl flooring.
d. Large openings, such as garage entrance etc., should be provided with 12-inch wide grade beams
founded at the same depth of the adjacent load bearing foundations.
e. Post-grading supplemental soil expansion testing is recommended in order to provide revised
recommendations, if warranted.
f. Establishing and maintaining positive drainage away from structural pads.
4.5 Conventional Concrete Slab-on-Grade
The prepared subgrades to receive footings as described, should be adequate for concrete slab-
on-grade placement. For normal load bearing conditions, 4-inch thick (net) concrete slabs
reinforced with #3 rebar at 24-inch olc, is recommended. For driveways, concrete slabs should
be 5.5-inch thick (n ominal) placed over local soifs compacted to at least 95%. Driveway slab
reinforcing, along with construction and expansion joints should be incorporated as required by
the project structural engineer.
Within moisture sensitive areas, concrete slabs should be underlain by 2-inch of compacted
clean gravelly sand of SE greater than 30, followed by 6-mil thick Visqueen.
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Subgrades to rece ive concrete slabs should be moistened as would be expected in any such
concrete placement. Low-slump (4"-5") concrete is recommended with water/cement ratio not
exceeding 0.5. In addition, it is strongly recommended that utility trenches underlying concrete
slabs and driveways should be adequately backfilled with gravelly soils and such should be
mechanically compacted prior to concrete pour. Water jetting should not be considered as an
alternative to mechanical compaction, Slab subgrades should be verified by soils engineer
immediately prior' to concrete pour.
4J3 Resistance to Lateral loads
Resistance to lateral loads can be restrained by friction acting at the base of foundation and by
passive earth pressure. A coefficient of friction of 0.29 may be assumed with normal dead load
forces for footing established on compacted fill.
An allowable passive lateral earth resistance of 230 pounds per square foot per foot of depth
may be assumed for the sides of foundations poured against compacted fill. The maximum
lateral passive earth pressure is recommended not to exceed 2300 pounds per square foot.
For design, lateral pressures from local soils when used as level backfill may be estimated from
the following equivalent fluid density:
Active:
At Rest:
33 pet
60 pet
]
4.7 Shrinkage and Subsidence
It is our opinion that during grading, the upper soils may be subjected to a volume change.
Assuming a 90% relative compaction for structural fills and assuming anoverexcavation and re-
compaction depth of 60 jnches, such volume change due to shrinkage may be on the order of
18 to 20 percent within canyon bottom. Lesser shrinkage may be expected within areas of ridges
and plateau. Further volume change may be expected due to supplemental shrinkage during
preparation of subgrade soils. For estimation purpose, such may be approximated to about
2-inch when conventional construction equipments are being used,
4.8 Construction Consideration
4.8.1 Unsupported Excavation
Site soils may be highly susceptible to caving. Temporary excavations up to 5 feet in vertical
height may be made without rigorous lateral supports. Excavated surface should, however, be
'wetted' during construction in order to minimize potential surface soil ravelling. Further, no
surcharge shall be allowed within an imaginary 1: 1 line drawn upward from toe of temporary
excavations. Flatter slopes should be considered.
4.8.2 Supported Excavations
If vertical excavations exceeding 5 feet in depths become warranted, such should be achieved
using shoring to support side walls.
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4.9 Site Preparations
Site preparations should include subexcavation of the upper loose and disturbed soils, stock-
piling, moisturization by overnight sprinkler or aeration to 3% to 5% over optimum moisture
content. Site preparation should also include re-placement of the excavated soils and other
approved imported fills compacted to 90 percent or better. Such earth work should be in
accordance with the applicable grading recommendations provided in the cummt use and as
recommended in Section 50 of this report
4,10 Soil Caving
Considering dry in nature, the site soils are considered susceptible to caving_ Temporary
excavations in excess of 5 feet should be made at a slope 2 to 1 (h:v), or flatter, and as per the
construction guidelines as provided by the CalOsha.
4.11 Structural Pavemen.t Thickness
Flexible Asphalt Paving: Based on estimated Traffic Index (TI) and on assumed soil R-value
of 50, the following paving sections are supplied for estimation purposes_ Following mass
grading, actual paving sections should be determined based on R-value of the soils sampled
from street grade.
Service Area Traffic Index, TI Paving Type Paving Thickness, in.
Interior Street 6.0 a.c over base 35 over 4"
For a.c over base, upper 12-inch of the subgrade soils should be compacted to 90% along with
the base material being compacted to minimum 95%_
4.12 Retaining Wall
Earth retaining walls, if any, should be designed based on the following Equivalent Fluid Density:
Slope of Retained Material (H:V) Equivalent Fluid Density, pef
Clean Sand Local Soil
level 30 34
2:1 42 55
Walls adjacent to traffic areas should be designed to resist a uniform lateral pressure of 100
pounds per square foot, which is a result of an assumed 300 pounds per square foot surcharge
behind the walls due to normal traffic. If the traffic is kept back ten feet from the wall, the traffic
surcharge may be neglected.
The design parameters do not include any hydrostatic pressure build-up. Consequently,
installation of 'french-drain' behind retain ing walls are recommended to minimize water pressure
build-up behind retaining wails_ Use of impervious material is preferred within upper the 18
inches of the backfill placed.
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Backfill behind retaining wall should be compacted to a minimum 90 percent. Flooding and/or
jetting behind wall should not be permitted. Local sandy soils may be used as backfill.
4.13 Utility Trench Backfill
Utility trench backfill within the structural pad and beyond, should be placed in accordance with
the following recommendations:
o Trench backfill should be placed in 6 to 8,"inch thick lifts and mechanically compacted to
minimum 90 percent. Jetting is not recommended as a substitute for mechanical
compaction. Within paving areas, the upper 12..inch of the backfifls should be compacted
to minimum 95%.
o Exterior trenches along foundations or a toe of a slope extending below a 1:1 imaginary
line projected from outside bottom edge of the footing or toe of the slope, should be
compacted to 90 percent of the Maximum Dry Density for the soils used as backfill. AI!
trench excavations should conform to the requirements of Cal-Osha
4.14 Seasonal Limitations
No fill shall be placed, spread or rolled dunng unfavorable weather conditions. Where the
work is interrupted by heavy rains, fill operations shall not be resumed until moisture conditions
are considered favorable by the soils engineer.
4.15 Planters
To minimize potential differential settlement to foundations, planters requiring heavy irrigation
should be restricted from using adjacent to footings. In event such becomes unavoidable,
planter boxes with sealed bottoms, should be considered.
4.16 Landscape Maintenance
Only the amount of irrigation necessary to sustain plant life should be provided. Pad drainage
should be directed towards streets and to other approved areas away from foundations. Slope
areas should be planted with draught resistant vegetation. Over watering landscape areas could
adversely affect the proposed site development during its life-time use.
4.17 Observations and Testing During Construction
The tentative recommendations provided are based on the assumption that supplemental
detailed geologic and geotechnical evaluations should be made and structural footings and slab-
on-grade be established exclusively into compacted fills. Excavated footings should be inspected,
verified and certified by soils engineer prior to steel and concrete placement to ensure their
sufficient embedment and proper bearing as recommended. Structural backfills discussed should
be placed under direct observations and testing by thiS facility. Excess soils generated from
footing excavations should be removed from pad areas and such should not be allowed on
subgrades underlying concrete slab.
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4.19 Plan Review
No grading and/or development plans are reviewed and none such are available at this time.
Consequently, the recommendations supplied are exclusively for preliminary project review only,
and should not be used in design and construction without written approval by soils engineer and
the project geologist. In addition, it is recommended that 'precise' grading, development and
structural pfans should be reviewed to ensure applicability of the assumptions made in preparing
this report. If during supplemental investigation conditions are observed different from those as
assumed and described herein, revised and/or supplemental recommendations will be required.
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5.0 Earth Work/General Grading Recommendations
It is assumed that site preparations and grading should involve overexcavation and replacement
of local soils as structural fill compacted to the minimum relative compactions as described
earlier. The following tentative recommendations may be considered for initial project review
only.
Structural Bacidilt
local soils free of debris. large rocks and organic should be considered suitable for reuse as backfill.
Loose soils, formwork and debris should be removed prior to backfilling retaining walls. On-site sand
backfill should be placed and compacted in accordance with the recommended specifications provided
below Where space limitations do not allow conventional backfilling operations, special backfill materials
and procedures may be required Pea gravel or other select backfill can be used in limited space areas.
Recommendations for placement and densification of pea gravel or other special backfilt can be provided
during construction.
Site Drainage:
Adequate positive drainage should be provided away from the structure to prevent water from ponding and
to reduce percolation of water into backfill. A desirable slope for surface drainage is 2 percent in landscape
areas and 1 percent in paved areas. Planters and landscaped areas adjacent to building perimeter should
be designed to minimize water filtration into subsoils. Considerations should be given to the use of closed
planter bottoms, concrete slabs and perimeter subdrains where applicable.
Utility Trenches:
Buried utility conduits should be bedded and backfilled around the conduit in accordance with the project
specifications. Where conduit underlies concrete slab-on-grade and pavement, the remaining trench backfill
above the pipes should be placed and compacted in accordance with the following grading specifications
General Grading Recommendations:
Recommended general specifications for surface preparation to receive fill and compaction for structural
and utility trench backfill and others, are presented below.
1. Areas to be graded, backfilled or paved, shall be grubbed, stripped and cleaned of all buried and
undetected debris, structures, concrete, vegetation and other deleterious materials prior to grading.
2. Where compacted fill is to provide vertical support for foundations, all loose, soft and other
incompetent soils should be removed to full depth as approved by soils engineer, or at least up to
the depth as previously described in this report. The areas of such removal should extend at least 5
feet beyond the perimeter of exterior foundation limit or to the extent as approved by soils engineer during
grading.
3. The fills to support foundations and slab-on-grade should be compacted to minimum 90% of the soil's
Maximum Dry Density at 3 to 5% over Optimum
To minimize potential differential settlements to foundations and slabs straddling over cut and fill
transition, cut portions following cut, should be further overexcavated and such be replaced as engineered
fill compacted to at least 90% of the soil's Maximum Dry Density as described in this report.
4. Utility trenches should be backfilled with granular material and such should be mechanically
compacted to at least 90% of the maximum density for the material used.
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5. Compaction for structural fills shall be determined relative to the maximum dry density as
determined by ASTM 01557-91 compaction methods. All in-situ field density Of compacted fill shall
be determined by the ASTM 01556-82 standard methods or by other approved procedures.
6. All new imported soils. if required, shall be clean, granular, non-expansive material or as
approved by the soils engineer.
7. During grading, fill soils shall be placed as thin layers, thickness of which following compaction shall
not exceed six to eig ~lt inches.
8 No rocks over six to eight inches in diameter shall be permitted to use as d grading material without
prior approval of the soils engineer
9. No jetting and/or water tampering be considered for backfill compaction for utility trenches without
prior approval of the soils engineer For such backfill. hand tampering with fill layers of 8 to 12 inches
In thickness, or as approved by the soils engineer is recommended.
10. Utility trenches at depth and cesspool and abandoned septic tank existing within building pad
areas and beyond, should be excavated and removed, or such should be backfilled with gravel, slurry
or by other material as approved by soBs engineer
11. Imported fill soils if required, should be equivalent to site soils or better. Such should be approved
by the soils engineer prior to their use.
12. Grading required for pavement, side-walk or other facilities to be used by general public, should
be constructed under direct observation of soils engineer or as required by the local public agencies.
13. A site meeting should be held between grading contractor and soils engineer prior to actual
construction. Two days of prior notice wi!! be required for such meeting.
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6.0 Closure
The conclusions and recommendations presented are based on site reconnaissance and on soil
sampling from exposed slope surtace and from leve! grades. No detailed geotechnical
explorations and made. Consequently, the recommendations supplied should be considered as
"tentative" subject to verification following actual geotechnical and geologic investigations.
Final grading and foundation plans should be reviewed by this office when they become
available. Site gradi ng must be performed under inspection by geotechnical representative of this
office. Excavated footings should be inspected and approved by soils engineer prior to steel and
concrete placement to ensure that foundations are founded into satisfactory soils and
excavations are free of loose and disturbed materials.
A pregrading meeti ng between grading contractor and soils engineer is recommended prior to
construction preferably at the site, to discuss the grading procedures to be implemented and
other requirements described in this report to be fulfilled
This report has been prepared exclusively for the use of the addressee for the project
referenced in the context. It shall not be transferred or be used by other parties without a
written consent by Soils Southwest, Inc. We cannot be responsible for use of this report by
others without inspection and testing of grading operations by our personnel.
Should the project be delayed beyond one year after the date of this report, the
recommendations presented shall be reviewed to consider any possible change in site
conditions.
The recommendations presented are based on the assumption that the necessary geotechnical
observations and testing during construction will be performed by a representative of this office.
The field observations are considered a continuation of the geotechnical investigation performed.
IF ANOTHER FIRM IS RETAINED FOR GEOTECHNICAL OBSERVATIONS AND TESTING, OUR PROFESSIONAL
LIABILITY AND RESPONSIBILITY SHALL BE LIMITED TO THE EXTENT THAT SOilS SOUTHWEST, INC. WOULD
NOT BE THE GEOTECHNICAL ENGINEER OF RECORD. FURTHER, USE OF THE GEOTECHNICAL
RECOMMENDATIONS BY OTHERS WilL RELIEVE SOilS SOUTHWEST, INC. OF ANY LIABILITY THAT MAY
ARISE DURING LIFETIME USE OF THE STRUCTURES CONSTRUCTED.
IT SHOULD BE NOTED THAT A LETTER OF TRANSFER OF RESPONSIBILITY SHOULD BE PREPARED BY
OTHER GEOTECHNICAL CONSULTANT AND SUCH BE SUBMITTED TO THE CITY FOR THEIR APPROVAL AND
TO SOILS SOUTHWEST, INC. PRIOR TO SITE PREPARATIONS AND GRADING.
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7.0 APPENDIX A
Field Explorations
No actual field explorations are included within the scope of work described. However, where
feasible, relatively undisturbed soils were sampled using a drive sampler lined with soil sampling
rings. The split ba rrel steel sampler was driven into the bottom of test excavations at various
depths. Soil samples were retained in brass rings of 2.5 inches in diameter and 1.00 inch in
height. The central portion of each sample was enclosed in a c1ose~fitting waterproof container
for shipment to our laboratory. In addition to undisturbed sample, bulk soil samples were
procured as described in the logs. Considering trench excavations, in-situ density testing was
programmed either by Sand-Cone or by Nuclear Density Gauge.
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8.0 APPENDIX B
Laboratory Test Programs
Laboratory tests were conducted on representative soils for the purpose of classification and
for the determination of the physical properties and engineering characteristics The number
and selection of the types of testing for a given study are based on the geotechnical conditions
of the site. A summary of the various laboratory tests performed for the project is presented
below
Moisture Content and Dry Density (D2937):
Data obtained from these test, performed on undisturbed samples are used to aid in the classification and
correlation of the soils and to provide qualitative information regarding soil strength and compressibility
Direct Shear (03080):
Data obtained from this test performed at increased and field moisture conditions on relatively
remolded soil sample is used to evaluate soil shear strengths. Samples contained in brass sampler
rings, placed directly on test apparatus are sheared at a constant strain rate of 0.002 inch per minute
under saturated conditions and under varying loads appropriate to represent anticipated structural loadings.
Shearing deformations are recorded to failure. Peak and/or residual shear strengths are obtained
from the measured shearing load versus deflection curve. Test results, plotted on graphical form, are
presented on Plate B-1 of this section.
Consolidation (02835):
Drive-tube samples a re tested at their field moisture contents and at increased moisture conditions since
the solis may become saturated during life-time use of the planned structure
Data obtained from this test performed on relatively undisturbed and/or remolded samples, were used
to evaluate the consolidation characteristics of foundation soils under anticipated foundation loadings.
Preparation for this test involved trimming the sample, placing it in one inch high brass ring, and loading
it into the test apparatus which contained porous stones to accommodate drainage during testing.
Normal axial loads are applied at a load increment ratio, successive loads being generally twice
the preceding.
Soil samples are usually under light normal load conditions to accommodate seating of the apparatus.
Samples were tested at the field moisture conditions at a predetermined normal load. Potentially moisture
sensitive soil typically demonstrated significant volume change with the introduction of free water The
results of the consolidation tests are presented in graphical forms on Plate B-2.
Potential Expansion
Considering sandy gravelly in nature, the site soils are considered non-expansive. Supplemental soil
expansion testing is suggested to verify the soil's expansion potential following site grading completion.
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Laboratory Test Results
Table I: Expansion Index, EI (UBe 29-2)
~~__ Soil Des",!~____ _____ Expansion ..In~'~-'-___'~_I
Sand-dark reddish brn, slightly silty, fine to 17 (very low expansive) J
medium coarse, gravelly, traces of clay
(central ridge area)
Table jlL Max. Density/Optimum Moisture Content (ASTM 01557-91)
-
Sample location, @ Depth. ft Max. Dry Density, pef Opt. Moisture (%)
Central Ridge Area 130 9
Northern Commercial Area 118 13
Page 24
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Arrowhead Springs Mixed-Use Development
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PROJECT NO.
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160
PROJECT NO.
Arrowhead Springs Mixed-Use Development
City of San Bernardino
San Bernardino, California
PLATE
SOILS SOUTHWEST INC.
Consulting Foundation Engineers
D-29
2.0
2.5
FRICTION
( degree)
34
05027-F1
A-2
4-
Z
0
~
t--;
~ 6.
Q
~
~
0
r./J
Z 8-
0
U
t-<
Z
~
U lO-
p::;
~
~
12-
CONSOLIDATION TESTS
LOAD IN KIPS PER SQUARE FOOT
.5
2
30
3
4
8
I')
2
-- ~-
-- ...
-~
-
New Hotel @ 0-2 ft., bulk-remolded to 90%
-
-
14-
. WATER PERMITTED TO CONTACT SAMPLE
Arrowhead Springs Mixed-Use Development
City of San Bernardino
San Bernardino, California
PROJECT NO.
PLATE
05027-F1
A-3
SOIlB SOUTHWEST INC.
Consulting Foundation Engineers
D-30
Arrowhead Springs/San Bernardino
Pags 25
05027-F1
Appendix C
Supplemental Seismic Design Parameters
Febr1J_3'l 2005
ssw
c.'ut'. (J"";\l\A 0, ,jJSIO... -:If ,.....N:t9 ....N:) Gj;-Ol-.~'"
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'I'''"' ...1 , ~.j",,, .,,,,,,"'l.
STATE OF CALIFORNIA
~l T"~ td8l11,~.;..:'~ ':-'\'..."" ~~~. "'1\~;1;!<i" '~'.IH "..~ '~..l .t'';'''1V
"'I '1'...~r '1~ I~ I'""",,, '"" ~ ",,,,,oj ~~., '~~'i'..r ~~... '0; ..,!~, ,~~l ~ "-,,,::t).
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":W~ .~', u.~ ~ICl ::'l-I;..~~t:l ~J"~ l".~ 'ffl14- ~!Jo''f'~.,i'''''.n
SPECIAL STUDIES ZONES
.o.l",::I, 1l"W'''' ........."....'''''- ""ee I'~I<.,I <;.h-"'c.~!ld\ mu~;
.". i.-.r ~1tI..... ')",,"'1,,11, C H".d ~l::.e~ '-.:-",~,-''''!o tlot ,'~~ Yo:
'I' t-;;- r"1;l ";U\lbi. d t':~il~'1;:lr\' !~t" t..~
CilfllUl,.g j..n ~t'l""ph~f~ ,...,...
CJ-!-W~"" 1 llo, \>>,r~"- .lI ..t ll.... COlllrolJ~II'. f>uhI>e Q.I~:Unf;ll' CCcl6
..: r 4,~ ~ "'~--lI''''':I",..,.. ::"'~ ...,~ " .......' ~..,t"'="'\Irll,) "'JI~~ ~r, 0) :x::
:l:""'.~ b.... '...ro.-....il:tCl' ~01::p!t:lt'...'~liti>>~'lII ,,:r,.:; Ii'S it>~:'-;i) ~
r.J=..l."'t!'1 _'r~r C''''ll;t"" ~:>. ;::: ~I~"" 2.500<....11 'I'I~.~ ;.-1 :~ Gw,",-".,
. ,,.. l-'~t',., """':kI.t?o~ (;.~v~
:sp..:..! Sht<:l_ Zll'I'I'" ee14"',,..5
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,.4 :.. ~',I'n '''0 ol-f ~:::"f: ~PI~~; "t,o<1<~ ~"T'O
~..-'l"'~"~
SA~' BERNARDiNO NORTH OUADRANGL!:;
'1:~C<l~..~;':: .~~~o j.~ <;.;..-1'..... ';!;",';..': ;;''''f~.
L: ,'<e...",,,.. .'OJ.....( :.n ," 1:"~ t:~...""~-:tt.
OFFICIAL MAP
Effective; J~if 1, 1914
,,'
... ...:.:.:~--' Siale Geo:-o;ist
r '_'. "'~~Cl". ,.. ~",.,....,,,.._._.,......,~.,g,-,,,..........,,.
::,;:.,::--':~ :..~'=;';'= ~ '"-.-,~ ,0" ..". p, ~.... .._ t.. ~ "_~." ,.... ........~
,... ,...."'...'l..'~ .;",......"~~".r,~<.."'....,'~.,.',..',..,,..,<.
'.., r__...".... :" 'h'" , 'j ,'.. '*" 1."" """''''~
D-32
.... ,'" '.;'..,.......<' '.. ....,......." ...,.,',',-.-1 """'0' ',," ~ <"'.,.",... . ....,...
:-:' ;~.~~;.~.':;~~;'.: '., j....,.., ,,>.:., h.'r....'~.'<;~....'., ~~.' ." .."..'
"",.
~.':',
"
fa
-
..
Arrowhead Springs Specific Plan
rroCu>;;1:m, L.J~~
o.UIJI=lI.l:ad. Bi<J 9,",',
St2:tl:>ROUl.e18
ALQUIST-PRIOLO EARTHQUAKE ZONES
Maximum Proposed
R:o;s(i?ntiil' ~ i 350 '.Jnti;
DISTRICT lAND lJS!"' ACREAGE
CG.1-H/S HistorJ.c Ho1p.! and COf1terellce CentB'f 25.0
CG.HIIS Spa, Health Club and Historic Pool 220
RMAV Residential Hillio",n OiJ
PCA lS.Hole Golf Course 1990
HMO\! Golf Course Residential Nortc 540
RM-SV G~1f Course Resldenlial Soutr, 12t
RL Residential 3~c
CR-2 InternatiOnal H01€1 7.0
CR-2 Corporate ON;!;:::! Corup~~A ~4,D
CA-2 Vtliage Walk aoo R€5idenlial ',0
CG 1 WP Windy Pomt jReb'auram[W,ne-T .sling; ~ ;~
eG.l Con'lmercial GenBral 0.,'
SuOlo1,,1 ~[[.;,~
OSjW Open SpaC<J,Waler5ned 1400.0
MWD Melropolilan Wal,,' Dislrtct 102
TOTAL ACRES 1916.0
~;::R~~i:.ii~'~i!i
f~~J'~:~r~;r!
(jl:i Wm:::'mB~. C-1n\/O!1 M~Ll.d
m 24:JtiE~
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I
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....... ...... -..
""cvmend" Roae RM SV .... bIl "'" Ie
1." ! 22ac.res I
~\ t. ,:~,~"~~: S.n~' ~Ii'g' i
~ - I
~ '< \ I
~:.h('l ·
~ I
~ I
~___..~________.M~~~P.._____~
OS{lr.{
~.21 at.:
OSfW
79.74 a:.
OSNv
1.04ac.
OSiW
20.,.
OS!W
naN~
~_~~_Q~m~___~~__.~.
MWO
1O.i: acres
\
Source: American Development Group
0';;i.'
23 ~1 C\~r~:-
:,:}~~;!l#?.!'!~t~
,~}>~~~
,'.:
RM.lJV 52ur..r",
25;,:,"l;,:
PCR
93 a(fe~
RM.DV
371 tmilS
,Sil-C!f['
aSNi
~J ,St
eG.!
0.7 ac~es
~
.
~
E
~
~
Alquist-Priolo
Earthquake Zone
Not to Scale
[1)',
. ,
i'i
\ ./
I....~..
Figure 5.6
D-33
**~:~*****k*************
* *
* U B C .':J E I "
;, *
Versiun L03 A
k********~:*****~*******
COMPUTATION OF 1997
UNIFORM BUILDING CO[)E
.':Jt;ISJVl1C DE~)IC;N PARAMETERS
JOB NUlVJBER: OS027-Fl
DATE: 02-1,-2005
,JOB NAME: Tra nstech
Arrowhead Springs Sun BellldnliIlO
t'/\ULT [)AtA-l:'ILE~ NAIV1!;;: CDM(~lJDC:R. rJAT
Sl'1'E: COOIWINA'l'E.':J:
SITE LATITUDE:
SITE LONGITUDE:
34.1805
117.2628
UBC SEISMIC ZONE:
0.4
0BC SOIL PHUFILE TYVE:: .':J[)
NEAREST TYPE A FAULT:
NAME: SAN }'l.NDREAS - Suuth<>rll
DI.':JTANCE: 0.0 kill
NEAREST TYPE B FAULT:
NAME.:: NOHTH l:'J:ZON'l'AL FAULT ZONE (West)
DISTANCE: 9.h km
NEAREST TYPE C E~ULT:
NAME:
DISTANCE: 99999.0 km
SELECTED use SEISMIC COEFFICIENTS:
Nd: 1.5
Nv: 2.0
Co.: 0.66
Cv: 1. 28
Ts: U.776
To: 0.155
*-k~j l l-k***k******{~k**~***k*****************************************
The digitized d~ta points used to model faults are *
limited ill number and have been digitized from small- *
scale maps (e.g., 1:750,000 scale) _ Consequently, *
the estjmated fault-site-distances may be in error by *
* several kilometers. Therefore, i.t is irnportarlt thaL *
* thc distctIlCes oe carefully checked for accuracy i'mcl ;,
* ddju~ted as needed, before they are used in design. *
**********k******k**************************************************
* CAUTION:
*
Page 1
D-34
SUMMARY OF F'A(JLT PARl\ME:TERS
i:}age 1
I APFROX.ISOUkCS : ~~Xo
ABBREVTATED IDTSTANCEI TYPF MAG
FllJJLT NAME I '!km) I (A, B,C) 1 (1VJ1e'I)
==================================1========1=======1======
Sl\.N 1\NDI,zEI\S - SO~Jthern 0 ~ 0 I Po... i r7!1
NORTH FlWNTPcL F.P,ULT znNf,: (\'i['2st) 9..6 B 7 , 0
CU:C;UORN CJ. 8 i1 6.5
SAN JACINTO-SAN BERNARr>INO u. 0 B G, 7
CUCAMONGA ! 15 . 8 A 7 . 0
SP.N JACINTO-SAN JACINTO VALLEY 19. U B 6.9
SAN ANrJREAS - 18:J1 Rllpture .211.2 A 7, fl
SAN JOSE 40 . 1 B 6, 5
SIERRA :V1ADR~; (Centrdl) 40.6 B 7,0
HELENDALE - S. LOCKHARD'T 10.7 I B 7,1
NORTH FRONTAL FhULT ZONE (East) 42.4 3 6.7
CHINO-Ct:;N'l'AAL AVE. (El::;inure) 46.0 B 6.7
ELSINORE-GLEN IVY 50.5 B G. 8
ELSINORE-WHITTIER 50.5 B 6.8
PINTO MOUNTAIN 51.7 B 7.0
CL]I~v[SHELL-.sAWPT'r 5LU R 6.=,
SAN JACINTO-ANZA S9. (I h 7.2
LENWOOU LOCKHART-OLD WOMAN SURGS 59.7 B 7.3
FLSINORF:-TEMECULA GO. ':J 13 6. l:I
,JOHNSON VALLEY (Northern) G5.7 R G.7
RAYl10ND 68.3 B 6. S
LANDERS 74.8 b 7.3
VERDUGO 7 G . 4 B 6. 7
EMERSON So. - COPPER MTN. 77 . 0 B 6.9
BURNT MTN. 79 .2 B 6. 5
EUREKA PEAK 00.:2 R 6.5
GRAVEL HILLS - HARPER LAKE 82.6 B 6.9
CALICO - HIDALGO 86.4 B 7.1
NEWPORT-INGLE\'IJOOD (L.A.Basin) U8.5 B 6.9
HOLLYWOOD 89. 3 B 6. 5
NEWPORT-INGLEWOOD (Offshore) 89.3 B 6.9
ELSINORE-JULIAN 92. 9 A 7 . 1
SAN GABRIEL 94. 7 B 7 . I)
PISGAH-BULLION MTN.-MESQUITE LK 95.1 B 7.1
SIERRA MADRE (San Fernando) 95.4 B 6.7
BLACKftJATER 95.8 B 6. 9
PALOS VERDES 1UJ. 5 B 7.1
SANTA MONICA 106.0 B 6.6
SAN JACINTO-COYOTE CREEK 106.8 B 6.8
SANTA SUSANA 114.4 B 6.6
M.l\.LIBU COAST 117.4 B 6.7
ROSE CANYON 118.4 B 6.9
CORONADO BANK 119.0 B 7.4
HOLSER 121.0 B 6.5
EARTHQUAKE VALLEY 128.1 B 6.5
ANACAPA-OUME 133.6 B 7.3
Page :..'
D-35
::.3LlL1
Rp,rrF;
, inni/yri
;~ .00
J "00
~j ~ 0 C
l:~ ~ 00
5.00
12.00
:-1/l. DO
O.SO
,-~~OO
0.60
O.SO
J..OO
5.00
2. SCI
2.50
U. '-)()
12.00
0.60
C:. 00
C.6D
0.50
0.60
C.5D
0.60
0.60
D.hO
0.60
0.60
l.DD
1. 00
1. 50
5.00
1. 00
0.60
L.D(]
0.60
3.00
L OD
4.00
5.00
0.30
1. SO
3.00
0.40
2.00
3.00
I FAULT
I "'YPF.
1 (SS,DSrBT)
~ 1 "--=~"~="'====
I 38
I CS
I c;S
I SS
OS
SS
C'C'
~ 1 L}
DS
US
('('
00
DS
DS
('('
00
SS
SS
DE)
53
S3
SS
('C"
.~ '-,
DS
5S
ns
55
53
C'C'
L)L)
5S
SS
SS
os
ss
('C"
L,)L)
S5
53
DS
55
,SS
lJS
S8
DS
DS
53
5S
OS
,~ C"
L) '-~
DC'
o
SUMMARY OF' FAULT PARAMETERS
Paye: 2
ABbJ:U,; 1/ IA TSI:
FAULT NAivlE
P. PP80X. I SOURC:~~ 1 MAX 0 i SL P FIVJLT
I DISTANCE i TYPE ! fVfAG l~P"Tt.: TYPE
! (Km) !(ll.,E,C)1 (11'-"1) (mm/yr) !(SS,DS,.I3T)
======1========1=======1======1=========1
f)AF( fUDGE (On:ci Lu.u;) 136.0 B 6,g 4.lJO US
GI\RLOCK ('West) 136.8 P. 7 4 (;.00 C"'C"'
, LJ \..J
G.qRLOCK (East) : 40. ! A 7 " i 7.00 '"'Q
,--, ,.)~
SAN CA'fETANO 140.7 B 6.G 6.00 US
SIMI~SAN'1'A ROSP, 141. -; i B G '} I.DO DS
SAN JACINTO - BORRECGO 147.1 13 6.6 4.00 <""
.,)0
SANTA YNEZ (Eust) 15G.5 B /.(J 2.DO SS
ELS INORF.-COYO'n.: MOUNTAIN 159.1 B 6.8 ~.OO t..~ L'
uoJ
OWL LAKE 11',1.8 B 6.5 2.00 S8
TANK CANYON 161. 8 i R (:-,. ~J 1. 00 OS
PANAMTN'T VALLEY 161.9 B 7 ..:~ 2.':>0 S;';
So. SIERRA NEVADA 162.0 13 7.1 0.10 DS
LITT LEo: LAKE 162.3 R 6. 'f 0.70 S8
PLEI1'O THRUST 164.3 B 6.8 /.00 US
WHITE TrJOLF 167.4 B 7.2 ;~ . 00 os
BRAWLr.:y SEISfVlIC ZONE 170.9 R 6.5 25.00 SS
VENTURA - PITA;'; POINT 173.7 B 6.11 1. 00 OS
BIG PINE 175.2 B 6.7 0.80 :.:;S
DEATH VALLEY (South) 1"76.4 l:3 6.9 4.00 58
~1. RIUGr.:-ARROYO PARIDA-SANTA ]\NA 177.9 B 6 'I 0.40 OS
SUPERSTITION i"n'N. (Sdn J'ac'iuto) 181. 2 B 6.6 5.00 SS
ELMORE RANCH 181.7 B 6.6 1. 00 SS
SUPERSTITION HILLS (San Jacinto) 184.9 B 6.6 4.00 SS
RED MOUNTAIN 187.1 B 6. f3 2.00 OS
ELSINORE-LAGUNA SALADA 206.3 B 7.0 3.50 SS
SANTA CRUZ ISLAND 208.4 B 6.8 1. 00 DS
IMPERIAL 210.2 A 7.0 20.00 S8
DEATH VALLEY (Graben) 212.0 B 6.9 4.00 OS
SANTA YNEZ (vvest) 2:20.4 B 6.9 2.00 SS
OWENS VALLEY 232.S B 7.6 1. 50 SS
SANTA ROSA ISLAND 243.8 B 6.9 1. 00 OS
HUNTER MTN. - SALINE VALLEY 255.2 B 7.0 2.50 SS
LOS ALAMOS-W. BASELINE 262.4 B 6.8 0.70 OS
DEATH VALLEY (Northern) 264.8 1'. 7.2 5.00 S8
INDEPENDENCE 268.5 B 6.9 0.20 DS
SAN JUAN 270.2 B 7.0 1.00 S8
LIONS HEAD 279.2 B 6.6 0.02 OS
SAN LUIS RANGE (S. Margin) 28] . } B 7.0 0.20 DS
CA8MALIA (Orcutt Frontal Fault) 294.4 B 6.') 0.25 OS
LOS OS08 310.3 B 6.8 0.50 OS
8.INCONAOA 323.6 B 7.3 1. 00 SS
HOSGRI 324.4 B 7.3 2.50 SS
BIRCH CREEK 325.3 B 6.5 O. 7 () OS
'tJH IT E NO[JNTAIN8 328.8 B 7.1 1. 00 SS
UEEP SPRINGS 346.3 B 6.6 0.80 OS
DL""'TH VALLEY (N. of Cucamongo) 349.6 A 7.CJ 5.00 SS
FCiqe 3
D-36
Page 3
SUMMARY OF FAULT PAR&fETERS
--------------------------------- ------- -----------------------------------
4BB8EVTA1'F:D
FAULT Nl\ME
APPROX. I SOUPCE i MAX. I S;~1F FP.llLT
I DISTANCE I TYPE ! MArc i RJ.I.'rE TiPS
(km) (A/B,C)! (["[H) I (mm/yr) IISS,DS;BT)
~=====i======I=========I==========
B 6. 8 I 1. 0 U I JS
B 5,L) I 34.00 I S8
R h.b i 0,20 I :JS
B 0.7 I ~~.,:J()! lJS
l:l 6 . 6 i 0 . ::! 0 DS
R 6. ':) I 1. 00 S3
B C.G ~.su US
E 6~2 15~OO S~
B 7.1 0.50 OS
B G.c:, LaO SS
B 7~O J~OO SS
B 6.5 0.50 os
B 6.8 0.10 S3
B 6.8 3.00 SS
A 7.9 24.00 S8
B fl.! 0.80 OS
B G.9 ~.oo SS
H 6~5 3~OO ss
A 7.3 5.00 SS
B 6.5 0.40 DS
B 6.9 1.00 DS
A 7.1 9.00 SS
B h.H 6.00 58
B C.9 6.00 SS
B 6.5 1.00 5S
A 7.0 9.00 SS
B 6.9 6.00 5S
B 6.8 0.30 DS
B 6.9 9.00 S8
B 6.5 0.60 S8
A 7.1 6.00 SS
A 7.1 9.00 88
A 7.1 ':l.00 58
B 6.8 6~OO ss
R 6.5 0.50 OS
B 6.7 6.00 S5
B 6.9 9.00 SS
A 7.4 35.00 OS
A 7.0 5.00 OS
B 7.1 0.70 OS
A 8.3 35.00 OS
B 7 . 0 (] . 60 OS
B 7.3 2.50 OS
B 6.9 0.60 DS
B/.U 0.60 OS
B 7.1 1.00 OS
-===========~=================:===- !
361,9
364.4
ROUND VALLEY (E. af S.N.Mtns.)
SAN ANDHEAS (Creeping)
FISH SLOUGH
HILTON CREEK
HAl:ZTLEY SPF.INGS
ORTIGALITA
MONO LAKE:
C]:\,LJ.WEAAS (So. ()f CaJavera.s
MONTEREY BAt - TOLARCITOS
QUIEN SASF'.
PALO COLORl~DO - SUP
ROBINSON CREEK
Zl\YANTE-VERGELI::S
SAHGENT
SAN ANDHEAS (1906)
ANTELOPE VALLEY
GREENVILLE
Hi\YWAJ:W (SE Extension)
SAN GREGORIO
MONTE VISTA - SHANNUN
GENOA
IlAYWAJ:ZU (Total Length)
CALAVERAS (No.of CdlaveLa3
CONCORD - GREEN VALLEY
WEST NAPA
RODGERS CREEK
HllNTING CREEK - BERRYESSA
POINT REYES
MAACAMA (South)
COLLAYOMI
BARTLETT SPRINGS
K~CAMA (Central)
MAACAMA (North)
ROUND VALLEY (N. S.F.Bay)
BATTLE CREEK
LAKE MOUNTAIN
GARBERVLLLE-BRICELAND
MENDOCINO FAULT ZONE
LITTLE SALMON (Onshore)
MAD RIVER
CASCADIA SUBDUCTION ZONE
[v!cKINLEYVILLR
TRINIDAD
FICKLE HILL
TARLE BLUFF
LITTLE SlU,MON (Offshore)
RRS)
Re3)
368.0
388,3
413,b
440.G
449.9
450.9
461.1
462.5
467.4
481.1
483.0
487.1
~,8 8. ?
522.0
53C.7
5:-14.6
535.0
536.9
548.6
':J'::d.2
5')3.2
597.7
636.CJ
637.4
656.6
66J .1
698.4
713.6
'Jl4.9
739.7
797.5
800.9
813.8
858.9
8'7 '} . 4
935.2
938.6
939.5
950.2
950.4
':)51. 5
95:2.4
9::;9.5
972.5
pagp- 4
D-37
Pugc 4
SUMMARY OF FAULT PARP~ETERS
--------------~~----_._._----------'~
----------------------.-----.-----
ABBREVI~TED
fAULT NAlVJE
SIC LhGOON - BALD M1'N.F'LT.ZONE
~**~*~**************************~*
AP PROZ. I SOURCE
! D1STA.NCE I TYPE
(km) I (~i\,G,C)
,~====cc I
987,5! B
):'**~I:_-,!,+-~4*i_!:J..A{.. ~
Page 5
D-38
~1AX SLIP tAULT
MAG~ ~~TE TYP~
(Mw! ! (mHL!YL) I (S8, DS, 8T)
=- -=!=========I==========
7.3 I 0.50 I os
k .k -.I. -J, .l. -.1..- * :.- * -j,: * -': -,~ k ..;. k -k .,}, '* ..". * * * * *' .,J~ '*
Spectral Acceleration (g)
o 0 ~ ~ ~ ~ N N N
III . . . .. . III . .
rn ~ 0 ~ rn ~ 0 N ~
o ~ 0 ~ 0 ~ 0 ~ 0
MII"I'II-'1
! i I I
. I I
-- --- _.__.~--t~._~_.~~ -....-.....--l.................
I I I II i
I I
I
I
0 0
. .
0 tv
0 (Jl
0
.
0
0
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,
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D-39
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**~********************
J. j- J. A ~ j- t..\;~). Jc-I. "1',-,I,.kx*~:,.+.k**+
UETERMINISTIC EST:::11ATION OF
PEAK p,CCELERATION [i'lWM DIGJl'lL:t..U tAULTS
JOB NUMBE:R: O~027~Fl
DATE: ()L'~ll ~2005
JOB NAME:: Transtech
Arrmvhe21d Springs San 8er'IlauiiIlo
CALCULATION NAME: 05027-Fl
FAULT~Dl\TA-FILE NAME: CDMGFLTE.DAT
SITE COORDINATES:
SITE LATITUDE;
SITE LONGITUDE:
34.18GS
117.2628
SEARCH RADIUS:
10 mi
ATTENUATION RELATION: 26) ~driss (1994)
UNCERTAINTY (M=Median, S=Sigma): M
DISTANCE MEASURE: rdist
SCOND: 0
Basement Depth: ~. (JU km Campbe LI
COMPUTE PEAK HORIZONTAL ACCELERATION
Horiz. - Soft Soil
Numhei" (jT Sigmas: 0.0
SSR:
Campbell SHR:
FAULT-DATA PILE USED: CDMGFLTE. OAT
MINIMUM DEPTH VALUE (kIn): 0.0
Paqe 1
D-40
EQFhULT SUMMARY
ut':n:RlV[INIST H~ SlTE PA;:ZAMETERS
Page I
1 ESTIMATED MAX, EARTHQrJAKF. r;:VENT
A2PROXH1ATE 1 ________n_____________________
DTSTi'lNC:!, 1 MAXIMUM I PEAK I EST. SITE
mi (kill) 1 EARTHQUAKE [ S TE I INTENS ITY
I 1 I1AC. (MH) [ ACCEL. 9 I MOD. MERe.
-===============================I==============I===~'======1==========1=========
SAN ANDREAS - Southern I O,O( 0.0) 1 7.11 1 iJ,:;ftj I X
SAN ANDREAS - San Bernurdino I O.O( 0.0) 1 7.3 I 0.570 I X
CLEGHORN I 6. I ( 9.8) 1 6.5 I 0.349 I IX
NORTH FRONTAL FAULT ZONF: (West) [ !.J( 11.'/) I 7.0 I 0.469 I X
SAN JACINTO-SAN BERNARDINO I '7. S ( 12.0)! (). 7 I ().::34 (~ I IX
C:UCA-MONGA : 9 . 8 ( 15 . 8) : 7 . 0 0 . 428 I X
*************.~ k***~~k*~*t***k***k****I~***kl~kLA*k~k**************************
ABRRF:VIAT ED
FAULT NAME
-END OF SEl\RCH-
6 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS.
THE SAN ANDREAS - San Bernardi no FAOLT IS CLOSK';T TO THl:<: :::;1 TE.
IT IS ABOUT 0.0 MILES (0.0 b-n) AWAY.
LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.5783 q
Page ;,>
D-41
450 -
400 -
350
300
250
200
150
100
50
~
o
~
-50
CALIFORNIA FAULT MAP
Transtech Arruwhead Springs San Bernardino
100
550
150
200
250
300
350
D-42
400
450
500
EARTHQUAKE MAGNl'fUDES & DISTANCES
Trans1ech l\rrowhead Springs San Bernardino
'7 c 4 - =------.~-~~<~--~~--.-".-".-"-.-..-.-.-.--...-~.---...-...-.---- ----- '---"~"~'-~'-~-<-l
I
7.3
7.2
7.1
~
~ 7.0
'-"' III .
Q)
'"0
:J cg
+J U.
C
0)
CO
~ 6.8
6.7 .
6.6
6.5
.
. 1
1
Distance (mi)
10
D-43
MAXIMUM EARTHQUAKES
Transtech Arrowhead Springs San Bernardino
r"'-"'-'--"'~''''''---''-''''----- -------
1'--
[
-
en
"-'
c . 1
0
.-
........
co
s....
())
-
(])
u
()
<(
.01
.001
1
-------.,,-------~~-------l
I
I
_ 1
1
Distance (mi)
D-44
10
STRIKE-SLIP F AUL TS
26) Idriss (1994) Horiz. - Soft Soil
M=5 M=6 M=7 M=8
~-_._.__._-----~---_._._.._-
1
~
~~~
~,
,~,
r'
0)
.........."
C .1
0
..~
-+-'
('V
5-
Q)
-
Q)
u
~
.01
.001
\
1 10 100
DistaA~e ladistl (km)
DIP-SLIP FAULTS
26) Idriss (1994) Hariz. - Soft Soil
-
M=7
M=5
r
r~--
M=6
M=8
1
~~~~~~,=
___~ " .. ._"."'&"'''''''.'''-~~~'''''''z,.''''='''''".~,.,"''~."
. -~~~~,~ "T,~:~00
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.", "'''''''',
"'"", ""","
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0)
'-'"
c . 1 ",
0
......... ~
Cti
5-
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-
Q)
0
u
<(
.01
.001
I
1 0 1 00
Distarltbe [adist] (km)
BLIND- TIlRDSTF AOL TS
26) Idriss (1994) lloriz. ~ Soft Soil
M~5 M~6 M~M~8
-~-~~\
~,_.
\~~. \
\
lr=
1
~<<~~"",r""""""-"""'_""'"""""""__", <<<
,.,-
9-
C-
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to
\0.-
m
-
(l)
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~
.1
~
,
"
'...
'"
.01
\
~
~\
'\0 '\00
Distance tadist1 (\<.01)
.00i
Arrowhead Springs/San Bernardino
05027-F1
PROFESSIONAL LIMITATIONS
Our preliminary investigation was performed using the degree of care and skill ordinarily exercised, under
similar circumstances by other reputable geotechnical consultants practicing in this general or similar
localities. No other warranty, expressed or implied, is made as to the cOilclusions and professional advise
included in this report.
The investigations are based on soil samples procured from exposed slope surface and from level areas
where accessible, consequently the recommendations provided shall be considered 'preliminary'. The
samples taken and used for testing and the observations made are believed representative of site
conditions; however, soil and geologic conditions can vary significantly between test excavations. If this
occurs. the changed conditions must be evaluated by the Project Soils Engineer and designs adjusted as
required or alternate design recommended.
The report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the information and recommendations contained herein are brought to the
attention of the project architect and engineers. Appropriate recommendations should be incorporated into
structural plans. The necessary steps should be taken to see that OLlt such recommendations in field.
The findings of this report are valid as of this present date. However, changes in the conditions of a
property can occur with the passage of time, whether they due to natural process or the works of man on
this or adjacent properties. In addition, changes in applicable or appropriate standards may occur from
legislation or broadening of knowledge Accordingly, the findings of this report may be invalidated wholly
or partially by change outside of our control. Therefore, this report is subject to review and should be
updated after a period of one year.
RECOMMENDEDSERV~ES
The review of grading plans and specifications, field observations and testing by the geotechnical
representative is an integral part of the conclusions and recommendations made in this report If Soils
Southwest, Inc. (SSW) is not retained for these services, the Client agrees to assume SSW's responsibility
for any potential claims that may arise during and after construction, or during the life-time use of the
structure and its appurtenant. The required tests, observations and consultation by the geotechnical
consultant during con struction includes, but not be limited to:
The tentative recommendations supplied should be considered valid and applicable subject to
supplemental detailed geologic and geotechnical investigation, as wefl as when the following conditions
are fulfilled:
I. Pre-grade meeting with contractor, public agency and soils engineer,
ii. Excavated bottom excavation inspections and verifications by soils engineer prior to engineered
fill soil placement,
/fl. Continuous observations and testing during site preparations and grading,
IV. Observations a nd inspections offooting trench excavations prior to steel and concrete placement,
v. Plumbing trench backfill placement inspections and compaction testing prior to steel and concrete
placement,
vi. Off-site and on-site utility trench backfill compaction testing and their verifications on on-call basis,
VII. consultations as required during construction, or upon request.
Page 26
Februrr-.4~ 2005
ssw
Arrowhead Springs/San Bernardino
05027-F1
Geologic Report
Page 27
Febrfjr.4~ 2005
ssw
JAMES R. EVANS, CEG 974
2926 HARRIS DRIVE
VlST A, CALIFORNIA, 92084
760~758-3176
February 12,,2005
Soils Southwest, 1ueo
897 Vi.a Lata, Suite N
Colton, Califomi~ 92324
Subject: Engineering Geologic Evaluation of the Arrowhead Springs Project
Gentlemen:
In accordance with your .request, we have perfonned preliminary geologic mapping
and evaluation of the proposed project. The evaluation included research of the Alquist-
Priolo zones with respect to the project in addition to examination of the numerous road
cuts and canyon slope exposures. The attached geologic map is a modification of an
enlarged portion of the Open File Geologic Map of the San Bernardino North
Quadrangle. The modifications include changes in geologic unit identificati.on when our
opinion differed from that shown on the map and identification oflandslides. In addition,
the property boundaries and Alquist-Priolo zones are shown on the map.
PROPOSED DEVELOPMENT
The project is to include expansion. of the existing hotel, adding conference faooiIities,
condominiums, and single family housing. Water sources exjst on site including hot
springs for heat sources. Grading details are not determined but "Will include leveling
terraces at various elevations for the different components of the project. Streets including
arterial width roads are to be consttucted to sen-e the project :including bridge
construction. Cuts of as much as fi:l:l:y feet are proposed.
SITE CONDITIONS
The existing hotel and grooods have been in existence since the 19405. These features
appear to be in good condition as are the bungalows. The southerly portion of the project
includes some fire damaged and abandoned homes. Aqueducts cross the project which
will have to be protected in place. Existing water tanks are to be removed as will portions
of the existing road system. Existing grading includes cut and fill grading for these roads
as well as the other existing developments including pipelines of various sorts.
Much of the site however, while not in pristi.ne condition is in a more ot" less natural
state. Watcnnan canyon on the west side has cut dOwn to bedrock during the past year as
D...50
Arrowhead Springs Project, San Bernardino
Page 2
has East Twin Creek and an unnamed tributary bordering the hotel ground on the west
side. AU of these drainages exhibit remnant boulders of enormous size.along the sides
and bottom.
REGIONAI/ GEOLOGY
The site is located at the base and extending up the flank of the San Bernardino
Mountains. These mountatns are composed of metamorphic and igneous rocks nmging .1u
age from Paleozoic to Cretaceous age. Stream and fan deposits emanating from thes
mountains reflect this diversity.
The southerly flank of these mountains is bounded by the San Andreas Fault zone
which is a designated Alquist-Priolo zone. Portions of these zones exist on the property
(see Geologic Map, Plate Gl).
SITE GEOLOGY
The site consist of ridges underlain by either Potato Fonnation or by granitic-
metllnorphic complex. These units are deeply weathered and are offset by faulting of
uncertain age. Hot springs travertines and quartz deposits mark the ridge exposures of
these faults as do active hot spri..Tlgs, Deep cut for roads aod tanks all exhibit the deep
weathering as do steep walled ravines cut into these crystaline basement units. The U. S.
G. S. map shows older rock where we have shown Potato Formation. Exposures show
bedding planes and rounded nodules in the weathered rock similar to previously
identified. Potato Formation Exposures which resulted in our reassignment ofthe units.
We also reclassified one of the Fan units to a rnudflow deposit due to a road cut
exposure and found two landslides not identified on the open file map. Other units
covering the basemen.t units were correctly mapped an remain unchanged.
Portions of Alquist-Priolo zones exist on the west side and southerly end of the
project. These active faults have not yet boen trenched to locate fault traces in a precise
manner.
SEISMIC SETTING
The entire site lies in the near source zone of the San Andreas Fault. It is 7 Km from
the near source zone of the Class B Frontal Fault system> 13 Km from this zone of the
Class A Cucumonga Fault system and 9 KIn from the near source zone of the San Jacinto
Fault
D-51
Arrowhead Springs Project
Page 3
Earthquakes on these faults could generate vibrations on site with maximum
horizontal accelerations ranging from 0.40 to 0.70 and 'With durations of strong shaking
exceeding 20 seconds
GROUNDWATER
Numerous hot springs as wen as conventional springs on the property testify to water
conducted in fractures in the rock Near surface water also has been reported to occur near
the traces ofthe San Andreas Fault in the southerly edge of the property in the fan and
other alluvial deposits which are offset by the fault(s).
SLOPE STABILITY
The cuts made in weathered bedrock materials are expected to be stable in generaL
Geologic inspection during grading however is imperative to ensure that no adversely
dippjng shear or bedding planes are exposed which would result in slope instabili'ty.
The existing landslide below the hotel grounds should be dealt with to prevent
blockage oithe creek.
SECONDARY HAZARDS
Liquefaction lS possible near the southerly end of the project due to the high
groundwater and will have to be further evaluated for mjtigation purposes.
When grading plans are nearing fmal stages, areas near steep natural slopes should be
evaluated for potential rockfall or mudflow and appropriate mitigation.
GEOLOGIC CONCLUSIONS
1) The d.evelopment can be constructed in a geologically safe and stable manner if
the finding and recommendations of this report are incorporated into project
design.
2) The Alquist-Priolo zones near the southerly edge of the project will require
trenching and detailed logging. Appropriate setbacks for structures for human
occupancy will be established at that time.
3) Faults shown on the attached geologic map should be evaluated with respect to
development plans and appropriately investigated.
4) It is our opinion based on existing exposures that cuts up to fIfty feet probably win
not require blasting.
5) Due to the nature of the bedrock aU cuts should be mspected by a qualified
geologist during grading
D-52
Arrowbead Springs Project> San Bem.ardino
Page 4
6) The site will experience at least one major earthquake during any reasonable
project lifetime with nigh accelerations and long duration.
7) Liquefaction potential requires further subsurface investigatian and evaluation at
the southerly end of the project.
8) Siting of buildings should be reviewed with respect to rockfall or mudflow.
potential at a later date for mitigation requ\rements- if any are required.
GEOLOGIC RECOMMENDATIONS
1) Grading plans should be reviewed. by this geologist
2) The project shQuld be graded under the inspection and approval af a qualified
sails engineer,
3) AU design professionals should review this report and incorporate appropriate
features into. project desigu_
This Investigation and this report have been prepared using current standards for the
profession of engineering geo.logy. No. other warranty is expressed ar implied. The repon
. . .
may be subject to review by local agencies. If this is the case, we are available for further
consultation. The user of this report should be aware that witho.Uf aU attachments and a
wet ink signature, the report is not a legal document. We appreciate this opportunity to.
have been of service to you.
VERY TRULY YOURS
JAMES R. EV ANS7 CEG 974- Exp.04
ATIACHMENTS
1) Geologic Map, Plate G 1
REFERENCES
1) Geologic Map of the San Bernardino North 7.5' Quadrangle, 2001, Miller, Matti
& Carson, U. S. G. S. Open File 01-131
2) Maps ofKnovm Active Fault Near Source Zones in California and Adjacent
Portions of Nevada, 1998, Prepared By C. D. M. G. Published By 1. C. B. O.
3) Alquist-Prialo San Bernardino North Quadrangle, 1988, C. D- M. G,
4) Landis Fairchild San Bernardino Area Photo-Map series, 1969 K43
5) Ground Motions And Soil Liquefaction During Earthquakes, 1982, Seed, H. R &
ldriss, I, M., Monograph E. E. Kl
AEIDALPHOTOGRAPHSUSED
D-53
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gl
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.,
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'"
OlS
Very Young
6~)osit3
v">cy YOllng ,!In
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'" OlJ" L
Q;~; '" dflow Q:}osits
\Older Nt!
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