HomeMy WebLinkAboutTract Map 3929 Lot 215 Rough Grading
I 1m INLAND, INC.
I Geotechnical Consulting
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GEOTECHNICAL REPORT OF ROUGH
GRADING, PROPOSED SINGLE FAMILY
RESIDENCE, ASSESSORS PARCEL NUMBER
921-180-004, LA SIERRA ROAD IN THE CITY
OF TEMECULA, RIVERSIDE COUNTY,
CALIFORNIA
Project No: I04734-30
Dated: February 8, 2005
Prepared For:
l'fIR. JOHN FRAZZINI
36735 Avenida Verde
Temecula. California 92592
40935 County Center Drive' Suite A' Temecula, CA 92591 . (951) 719-1076 . Fax (951) 719-1077
11m INLAND, INC.
I Geotechnical Consulting
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February 8, 2005
Project No. 104734-30
MR. JOHN FRAZZINI
36735 Avenida Verde
Temecula, California 92592
Subject:
Geotechnical Report of Rough Grading, Proposed Single Family Residence, Assessors Parcel
Number. 921-180-004, La Sierra Road in the City of Temecula, Riverside County, California
This report presents a summary ofthe observation and testing services provided by LGC Inland, Inc., (LGC) during
rough grading operations to develop the subject site in the City of Temecula, Riverside County, California.
Conclusions and recommendations pertaining to the suitability of the grading for the proposed residential
construction are provided herein, as well as foundation-design recommendations based on the as-graded soil
conditions.
The purpose of grading was to develop a pad for construction of a single family residence. The proposed structure
will be either a one- or two-story with wood or steel-framed construction and concrete slab-on-grade. Grading on
the subject pad began during December of 2004 and completed during January of2005.
1.0
REGULATORY COMPLIANCE
Removal and recompaction oflow-density surface soils, processing ofthe exposed bottom surfaces or placement of
compacted fill under the purview ofthis report have been completed under the observation and with selective testing
by LGC. Earthwork and grading operations were performed in accordance with the recommendations presented in
the referenced reports (see References) and the Grading Code of the City ofTemecula, California. The completed
earthwork has been reviewed and is considered adequate for the construction now planned. On the basis of our
observations and field and laboratory testing, the recommendations presented in this report were prepared in
conformance with generally accepted professional engineering practices and no further warranty is expressed or
implied.
2.0
ENGINEERING GEOLOGY
2.1
General
Geologic conditions exposed during the process of grading were frequently observed and mapped by LGC's
technical staff.
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40935 County Center Drive' Suite A' Temecula, CA 92591 . (951) 719-1076 . Fax (951) 719-1077
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2.2 Geoloeic Units
Earth materials within the site included colluvial clayey sands and Pauba Formation sandstones.
2.3 Groundwater
During over-excavations, no free groundwater was encountered.
2.4 Faultine
No faults were observed during grading operations on the site.
3.0 SUMMARY OF EARTHWORK OBSERVATIONS AND DENSITY TESTING
3.1 Site Clearine and Grubbine
Prior to grading, all grasses and weeds were stripped and removed from the site.
3.2 Ground Preoaration
A portion of the building pad area is located within a "cut area" which is approximately l5=" feet below
original ground. Once the pad was "cut" to finish grade, overexcavation within the cut portion of the
building pad, including 5 feet outside the building footprint, was over-excavated an additional 4 feet.
Fill in the building pad area is on the order of 20=" feet and in the form of a fill slope along the southern
portion of the pad.
Prior to placing till, the exposed bottom surfaces were scarified to depths of 6 to 8-inches, watered or
air-dried as necessary to achieve at or slightly above optimum moisture content and then recompacted in-
place to a minimum relative compaction of90 percent.
3.3 Disoosal of Oversize Rock
Oversize rock (rock generally greater than I foot in maximum dimension) was not encountered during the
removal operations.
3.4 Fill Placement and Testine
Fill materials consist of onsite soils. All fills were placed in lifts restricted to approximately 6 to 8 inches in
maximum thickness, watered or air-dried as necessary to achieve near optimum moisture conditions, then
compacted in-place to a minimum relative compaction of 90 percent by rolling with a bulldozer. The
maximum vertical depth offill placed within the subject pad as a result of grading is approximately 20 feet.
Field density and moisture content tests were performed in accordance with ASTM Test Methods D2922 and
D30l7 (nuclear gauge). Test results are presented on Table I (attached) and test locations are shown on the
enclosed Density Test Location Map (Plate I).
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Field density tests were taken at vertical intervals of approximately I to 2 feet and the compacted fills were
tested at the time of placement to verify that the specified moisture content and minimum required relative
compaction of 90 percent had been achieved. At least one in-place density test was taken for each 1,000
cubic yards of fill placed and/or for each 2 feet in vertical height of compacted fill. The actual number of
tests taken per day varied with the project conditions, such as the number of earthmovers (scrapers) and
availability of support equipment. When field density tests produced results less than the required minimum
relative compaction of 90 percent, the approximate limits of the substandard fill were established. The
substandard area was then reworked, moisture conditioned, re-compacted, and retested until the minimum
relative density was achieved.
Visual classification of earth materials in the field was the basis for determining which maximum dry density
value, summarized in Appendix B, was applicable for a given density test. One-point checks were
periodically performed to supplement visual classification.
3.5 Slooes
Slopes constructed within the subject house pad consist of moderate height 2: I horizontal to vertical (h:v)
fill slopes varying up to a maximum height of 20* feet. Prior to constructing the fill slopes, fill keys were
excavated a minimum of2 to 4 feet into the underlying bedrock. The fill key bottoms were angled back into
the slope and were a minimum equipment width wide.
The fill slopes are considered stable in their current configuration.
4.0 LABORATORY TESTING
4.1 Maximum Drv Densitv
Maximum dry density and optimum moisture content for the major soil types observed during grading were
determined in our laboratory in accordance with ASTM Test Method DI557-00. Pertinent test values are
summarized in Appendix B.
4.2 Exoansion Index Tests
Expansion index tests were performed on representative samples of soil existing at or near finish-pad grade
within the subject pads. These tests were performed in accordance with ASTM D4829-03. Test results are
summarized in Appendix B.
4.3 Soluble Sulfate Analvses
Water-soluble sulfate contents were also determined for representative samples of soil existing at or near pad
grade of the subject pads in accordance with California Test Method No. 417. These tests resulted in
negligible sulfate contents of less than 0.1 percent. Test results are summarized in Appendix B.
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5.0 POST-GRADING CONSIDERATIONS
5.1 Landscaoine and Maintenance of Graded Slooes
The slopes within the subject lot vary up to a maximum height of 20:t feet. Unless long-term mitigation
measures are taken, the slopes may be subject to a low to moderate degree of surficial erosion or degradation
during periods of heavy rainfall. Therefore, it is recommended that the slopes be landscaped with a
deep-rooted, drought-resistant, woody plant species. To provide temporary slope protection while the woody
materials mature, the slopes should be planted with an herbaceous plant species that will mature in one
season or provided with some other protection, such as jute matting or polymer covering. The temporary
protection should be maintained until the woody material has become fully mature. A landscape architect
should be consulted to determine the most suitable plant materials and irrigation requirements.
To mitigate future surficial erosion and slumping, a permanent slope-maintenance program should be
initiated. Proper slope maintenance must include regular care of drainage- and erosion-control provisions,
rodent control, prompt repair ofleaking irrigation systems and replacement of dying or dead plant materials.
The irrigation system should be designed and maintained to provide constant moisture content in the soils.
Over-watering, as well as over-drying, of the soils can lead to surficial erosion and/or slope deterioration.
Potential problems can develop when drainage on the pad and adjacent slopes is altered in any way.
Drainage can be adversely altered due to the placement of fill and construction of garden walls, retaining
walls, walkways, patios, swimming pools and planters.
5.2 Pad Drainaee
Drainage on the pad should be designed to carry surface water away from all graded slopes and structures.
Pad drainage should be designed for a minimum gradient of I percent with drainage directed to the adjacent
streets. After dwellings are constructed, positive drainage away from the structures and slopes should be
provided on the lots by means of earth swales, sloped concrete flatwork and area drains.
5.3 Utilitv Trenches
All utility-trench backfill within street right-of-ways, utility easements, under sidewalks, driveways and
building-floor slabs and 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 a LGC representative to verify
adequate compaction. Excavations for trenches that exceed 4 feet in depth should be laid-back at a
maximum gradient of I: I (h:v).
For deep trenches with vertical walls, backfills should be placed in lifts no greater than 2 feet in thickness
and then mechanically compacted with a hydra-hammer, pneumatic tampers or similar equipment. For deep
trenches with sloped walls, backfill materials should be placed in lifts no greater than 8 inches and then
compacted by rolling with a sheepsfoot tamper or similar equipment.
To avoid point-loads and subsequent distress to clay, cement, or plastic pipe, sand bedding should be placed
at least I-foot above all pipe in areas where excavated trench materials contain significant cobbles. Sand
bedding materials should be thoroughly jelled prior to placement of backfill.
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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.
6.0 FOUNDATION DESIGN RECOMMENDATIONS
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 residential structures. Foundation
recommendations are provided herein.
6.2 Allowable Bearine Values
An allowable bearing value of 1,500 pounds per square foot (pst) is recommended for design of 24-inch
square pad footings and l2-inch wide continuous footings founded at a minimum depth of l2-inches below
the lowest adjacent final grade. This value may be increased by 20 percent for each additional I-foot of
width and/or depth to a maximum value of2,500 psf. 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 1.I-inch. Differential settlement is expected to be about Y2-inch over a horizontal
distance of approximately 20 feet, for an angular distortion ratio of I :480. It is anticipated that the majority
of the settlement will occur during construction or shortly thereafter as building loads are applied.
The above settlement estimates are based on the assumption that the grading will be performed in
accordance with the grading 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 offriction ofOAO 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 placed directly against compacted fill or competent alluvium. In the
case where footing sides are formed, all backfill placed against the footings should be compacted to a
minimum of90 percent of maximum dry density.
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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 soils. 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.
Excavated 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.
6.6 Exoansive Soil Considerations
Results of the laboratory tests indicate onsite soil and bedrock materials exhibit an expansion potential of
VERY LOW as classified in accordance with 1997 UBC Table 18-I-B. The design and construction details
herein are intended to provide recommendations for the various levels of expansion potential.
6.6.1 Verv Low Exoansion Potential rExoansion 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 l8-l-B of the 1997 Uniform Building Code (UBC). Since the
onsite soils exhibit expansion indices of less than 20, 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 Footines
. Exterior continuous footings may be founded at the minimum depths indicated in UBC Table
l8-I-C (i.e. 12-inch minimum depth for one-story and IS-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 No.4 bars, one top and one
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 of24 inches square and founded
at a minimum depth of IS inches below the lowest adjacent final grade. No special
reinforcement of the pad footings will be required.
6.6.1.2 Buildine Floor Slabs
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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
of24 inches on center, both ways. All slab reinforcement should be supported on concrete
chairs or bricks to ensure the desired placement near mid-depth.
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. Concrete floor slabs should be underlain with a moisture vapor barrier consisting of a
polyvinyl chloride membrane such as 6-mil visqueen, or equivalent. A\llaps within the
membrane should be sealed, and at least 2 inches of clean sand be placed over the membrane
to promote uniform curing of the concrete.
. 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 No.4 bars, one top
and one bottom.
. Prior to placing concrete, the subgrade soils below all living-area and garage area floor slabs
should be pre-watered to promote uniform curing of the concrete and minimize the
development of shrinkage cracks.
6.7 Corrosivitv to Concrete
The National Association of Corrosion Engineers (NACE) 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 or various buried metallic elements such as rebar, piles, pipes, etc., which are in direct contact
with or within close vicinity of the foundation soil.
In general, soil environments that are detrimental to concrete have high concentrations of soluble sulfates
and/or pH values ofless than 5.5. Table 19-A-4 of the VB.C., 1997, provides specific guidelines for the
concrete mix design when the soluble sulfate content of the soils exceeds 0.1 percent by weight or 1,000
ppm.
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 ofU.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 II.
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 ofthe corrosion engineer may supersede
the above requirements.
6.8 Structural Setbacks
Structural setbacks in addition to those required in 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.
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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 35 pounds per cubic foot
(pet) 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: I (h:v), the above value should be increased to 52 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 up to 10 feet high that are restrained at the top, an at-rest earth pressure
equivalent to a fluid having a density of 53 pcf should tentatively be used for walls supporting a level
backfill. This value should be increased to 78 pcf for ascending 2: I (h:v) backfill.
7.2 Drainaee
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 l40N 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 I y, cubic feet per foot of ~- or I 'l1-inch open-graded gravel 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.
7.3 Temoorarv Excavations
All excavations should be made in accordance with OSHA requirements. LGC is not responsible for job site
safety.
7.4 Wall Backfill
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.
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8.0 MASONRY GARDEN WALLS
Footings for masonry garden walls should also be reinforced with a minimum of four No.4 bars, two top and two
bottom. In order to mitigate the potential for unsightly cracking, positive separations should also be provided in the
garden walls at a maximum horizontal spacing of20 feet. These separations should be provided in the blocks only
and not extend through the footing. The footing should be placed monolithically with continuous rebars to serve as
an effective "grade beam" below the wall.
In areas where garden walls may be proposed on or near the tops of descending slopes, the footings should be
deepened such that a minimum horizontal clearance of 5 feet is maintained between the outside bottom edges of the
footings and the face of the slope.
9.0 CONCRETE FLATWORK
9.1 Thickness and Joint Soacine
To reduce the potential of unsightly cracking, concrete sidewalks and patio type slabs should be at least 3 Y,
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.
9.2 Suberade Preoaration
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.
9.3 Drainaee
Drainage from patios and other flatwork areas should be directed to local area drains and/or graded-earth
swales designed to carry runoff water to the adjacent streets or other approved drainage structure. The
concrete flatwork should also be sloped at a minimum gradient of I percent away from building foundations,
retaining walls, masonry garden walls and slopes.
9.4 Tree Wells
Tree wells are not recommended in concrete- flatwork areas since they can introduce excessive water into the
sub grade soils or allow for root invasion, both of which can result in uplift of the flatwork.
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10.0 PLANTERS AND PLANTER WALLS AND LANDSCAPING
10.1 Planters
Planters that are located within 5 feet of building foundations, retaining walls, masonry garden walls and
slope areas should be provided with sealed bottoms and bottom drains to prevent infiltration of water into
the adjacent foundation soils. The surface of the ground in these areas should also be maintained at a
minimum gradient of2 percent and direct drainage to area drains or earth swales.
The sealed planter bottoms should consist of either reinforced concrete having a minimum thickness of 4
inches or a polyvinyl-chloride membrane of sufficient thickness to prevent puncturing by plant roots. If
concrete is used to line the planters, minimum reinforcement should consist of No. 3 bars spaced 18 inches
on centers, both ways, or 6-inch by 6-inch, No.6 by No.6 welded wire mesh. If a polyvinyl-chloride
membrane is used, a minimum thickness of 30-mil is recommended. Furthermore, the bottoms of the
planters should be sloped to direct subsurface water to collector drains connected to drain lines designed to
10.2 Planter Walls
Low height planter walls should be supported by continuous concrete footings constructed in accordance
with the recommendations presented for masonry block wall footings.
10.3 Landscaoine
In recognition that, as the homeowner, you will add either soft-scape or hard-scape after precise grading, the
following recommendations may be used as a guide. It is paramount that homeowners consult with a
professional engineer to ensure that the construction of future landscaping improvements will not cause
obstruction of existing drainage patterns or does not cause surface water to collect adjacent to the
foundation, creating saturated soils adjacent to the foundation.
Area drains should be maintained and kept clear of debris in order to properly function. Homeowners should
also be made aware that excessive irrigation of neighboring properties can cause seepage and moisture
conditions on adjacent lots. Homeowners should be furnished with these recommendations communicating
the importance of maintaining positive drainage away from structures towards streets when they design their
improvements.
The impact of heavy irrigation or inadequate runoff gradients can create perched water conditions. This may
result in seepage or shallow groundwater conditions where previously none existed. Maintaining adequate
surface drainage and controlled irrigation will significantly reduce the potential for nuisance type moisture
problems. To reduce differential earth movements such as heaving and shrinkage due to the change in
moisture content of foundation soils, which may cause distress to a residential structure and associated
improvements, moisture content of the soils surrounding the structure should be kept as relatively constant as
possible.
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10.4 Swimminf! Pools and Soas
No pools or spas are shown on the plans. In general, LGC does not recommend pools or spas be located
within 15 feet of the top of 2: I (h:v) slopes without special foundation design considerations. While
expansive soil related cracking of concrete flatwork and garden walls may only be cosmetic in nature, and
thus tolerable, such cracking in pools and/or spas cannot be tolerated. Soil expansion forces should be taken
into account for design and construction of a swimming pool and/or spa.
For soils having a Very Low expansion potential, we recommend a lateral earth pressure of78 pcfbe used
for design of pools/spa shells.
To avoid localized saturation of soils, landscaping of the backyard should not be planned with unlined
planter boxes in the immediate vicinity of the pool/spa shell.
The excavated material from the pool/spa area is often used to build elevated planter boxes and/or other
structures adjacent to the pool area. This practice imposes significant loads at the location of these structures
and induces differential settlements. This practice could jeopardize the integrity ofthe pool/spa and possibly
other improvements. Pool decking should also receive special design considerations, since the pool is
founded generally 5 to 6 feet below grade. If pool decking is not correctly designed for expansive soils,
differential movement between the flatwork and pool will occur. A geotechnical consultant should be
retained to evaluate the impact of planned improvements and provide proper recommendations for design.
Whether the pool/spa shell is in the zone of influence of the building or wall footing, the need for shoring or
support for the building or wall footing should also be taken into consideration.
11.0 POST GRADING OBSERVATIONS AND TESTING
LGC should be notified at the appropriate times in order to provide the following observation and testing services
during the various phases of post grading construction.
11.1 Buildine Construction
. Observe all footings when first excavated to verify adequate depth and competent soil bearing
conditions.
. Re-observe all footings, if necessary, if trenches are found to be excavated to inadequate depth and/or
found to contain signiticant slough, saturated or compressible soils.
11.2 Retainine Wall Construction
. Observe all footing trenches when first excavated to verify adequate depth and competent soil bearing
conditions.
. Re-observe all footing trenches, if necessary, if trenches are found to be excavated to inadequate depth
and/or found to contain significant slough, saturated or compressible soils.
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. Observe and verify proper installation of subdrain systems prior to placing wall backfill.
. Observe and test placement of all wall backfill.
11.3 Masonrv Garden Walls
. Observe all footing trenches when first excavated to verify adequate depth and competent soil bearing
conditions.
. Re-observe all footing trenches following removal of any slough and/or saturated soils and re-excavate
to proper depth.
11.4 Exterior Concrete Flatwork Construction
. Observe and test sub grade soils below all concrete flatwork areas to verify adequate compaction and
moisture content.
11.5 Utilitv- Trench Backfill
. Observe and test placement of all utility trench backfill.
11.6 Re-Gradine
. Observe and test placement of any fill to be placed above or beyond the finish grades shown on the
grading plans.
12.0 LIMITATIONS
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.
Our services were provided in order to form an opinion concerning the suitability of the proposed development
relative to the geotechnical aspects of the site. The data and information provided in this report are based on periodic
tests and observations made by representati ves of our firm during the grading and construction operations performed
by others. This report is not a warranty of the work performed by others. The presence of our personnel during the
work process did not involve the direction or supervision of the contractor.
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 architect
and/or project engineer and incorporated into the plans, and the necessary steps are taken to see that the contractor
and/or subcontractor properly implements the recommendations in the field. The contractor and/or subcontractor
should notify the owner if they consider any of the recommendations presented herein to be unsafe.
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The findings of this report are valid as of the present date. However, changes in the conditions ofa property can and
do occur with the passage oftime, whether they be due to natural processes or the works of man on this or adjacent
properties.
In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the
broadening of knowledge. Accordingly, the findings ofthis report may be invalidated wholly or partially by changes
outside our control. Therefore, this report is subject to review and modification, and should not be relied upon after a
period of 3 years.
This opportunity to be of service is sincerely appreciated. Please call if you have any questions pertaining to this
report.
Respectfully submitted,
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GEU/SMP/TMP/ts
Attachments: Table I - Summary of Field Density Tests (Rear of Text)
Appendix A - Reterences (Rear of Text)
Appendix B - Laboratory Test Criteria/Laboratory Test Data (Rear of Text)
Plate I - Density Test Location Map (In Pocket)
Distribution: (4) Addressee
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TABLE I
SUMMAKY OF FIELD DENSITY TESTS
Frazzini Kesidence
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_'" ..........t................i.....;. ..}P"l'....... Moi~t;Ure~'o, .J\ila,X'< ..'j(~I:'
1...._.......;;.
.r'1/.1 %.; 1;t;t!eY~fiOn;~ 'CblrisiYy' '. C"rlferthi Deh'S!ty; . c~t\jp.i
.ft ''1$' I~L'
~ L,' . ;.:;.~(fJ'et) : ',,'Vg.,'" ., .!l'cfL i(i)(,)
1 N 12/21/04 CF Privewav llGO 1 I1G.8 IO.G 129.5 90
2 N 12/12/04 CF Soulh fill 1145 2 114.0 11.1 12G.0 90
3 N 12/22/04 CF South fill 1147 2 113.5 11.5 12G.0 90
4 N 12/22/04 CF South fill 1149 1 117.2 9.0 129.5 91
5 N 12/23/04 CF Soulh fill 1151 I I1G.9 lOA 129.5 90
G N 12/23/04 CF South fill 1159 2 114.1 11.7 12G.0 91
7 N 12/23/04 CF South fill 1153 2 113.G 11.5 12G.0 90
8 N 12/23/04 CF North fill 11Gl 1 118.0 10.7 129.5 91
9 N 12/23/04 CF South fill 11G1 2 115.0 11.3 12G.0 91
10 N 12/27/04 CF South fill 11G2 2 108.5 11.7 12G.0 8G
11 N 12/27/04 CF Retest # 10 . 2 115.2 11.1 12G.0 91
12 N 12/27/04 CF Drivewav I1G3 2 I1G.0 I1.G 12G.0 92
13 N 12/29/04 CF House pad 11G2 2 114.2 11.0 12G.0 91
14 N 12/29/04 CF House pad 11G3 2 115.0 11.7 12G.0 91
15 N 01/17/05 CF House Dad 11G2 2 115.3 IO.G 12G.0 92
1G N 01117/05 CF House pad 11G:, 2 114.G 11.5 12G.0 91
17 N 01118/05 CF House pad IIG3 2 115.2 11.0 12G.0 91
18 N 01118/05 CF House pad I1G4 2 116.2 11.3 126.0 92
19 N 01118/05 CF House pad FG 2 115.7 12.1 126.0 92
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N - Nuclear Test Method
FG - Finish Grade
CF - Compacted Fill
February 2005
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APPENDIXA
REFERENCES
International Conference of Building Officials, 1997, Uniform Building Code, Structural Engineering
Design Provisions.
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APPENDIX B
Laboratorv Testine 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 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 tables summarizing the test results.
Exoansion Index: The expansion potential of selected samples was evaluated by the Expansion Index Test, ASTM
D4829. Specimens are molded under a given compactive energy to approximately the optimum moisture content and
approximately 50 percent saturation or approximately 90 percent relative compaction. The prepared l-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.
~4MPI.,E
Ji(JCATIOIV
House Pad
· Per Table 18-t-B of t997 UBC.
SAM}'L.g
DESCRIPTION
Clayey SAND
COMPACTED DRY
DENSITY (pcf)
112.7
EXPANSION
INDEX
17
EXPANSION
POTENTIAL *
Ve
Maximum Densitv Tests: The maximum dry density and optimum moisture content of typical materials were
determined in accordance with ASTM D1557.
SOIL SAMPLE MAXIMUM DRY OPTIMUM MOISTURE
TYPE DESCRIPTION DENSITY (pc}) CONTENT (%)
Yellowish-brown clayey
I fine to coarse sand with 129.5 9.5
traces of gravel
Olive-brown clayey fme
2 to coarse sand with traces 126.0 10.5
of gravel
Soluble Sulfates: The soluble sulfate contents of selected samples 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:
LOCATION SAMPLE SULFATE SULFATE
DESCRIPTION CONTENT (ppm) * EXPOSURE*
House Pad Clayey SAND 30 Negligible
· Based on the 1997 edition of the UnifonnBuilding Code (U.B. C.), Table No. 19-A-4,preparedbytheInternationaIConference
ofBuilding Officials (ICBO, t997).
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