HomeMy WebLinkAboutCDP 10-12; SMERUD RESIDENCE; GRADING PLAN REVIEW; 2010-08-20CHRISTIAN WHEELER
ENGINEEKING
August 20, 2010
Richard Smerud
do Martin Volk-
568 Compass Road
Oceanside, California 92054
RECEIVED
JAN 20 2011
WGNERING
DEPARTMENT
CWE 2100122.02
SUBJECT: GRADING PLAN REVIEW, PROPOSED BUENA VISTA WAY RESIDENCE
1099 BUENA VISTA WAY, CARLSBAD, CALIFORNIA
References: 1) Grading Plans for Richard Smerud Residence; The Sea Bright Company; Undated.
2) "Report of Preliminary Geotechnical Investigation, Proposed Buena Vista Way Residence",
Christian Wheeler Engineering; May 18, 2010 (CWE 2100122.01).
Dear Mr. Volk:
In accordance with a request from the Sea Bright Company, we have reviewed the referenced grading plans
for the subject project in order to ascertain that the recommendations presented in the referenced geotechnical
report have been implemented, and that no additional recommendations are needed due to changes in the
proposed construction. Based on this review, it is our opinion that in general, the plans reflect the
recommendations contained in the referenced report.
If you have any questions after reviewing this report, please do not hesitate to contact our office. This
opportunity to be of professional service is sincerely appreciated.
Respectfully submitted,
CHRISTIAN WHEELER ENGINEERING
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cc: (2) Submitted
(2) The Sea Bright Company
3980 Home Avenue + San Diego, CA 92105 + 619-550-1700 + FAX 619-550-1701
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I CHRISTIAN WHEELER
ENGINEEkING
REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION
I PROPOSED BUENA VISTA WAY RESIDENCE
1099 BUENA VISTA WAY
CARLSBAD, CALIFORNIA
SUBMITTED TO i.
RICHARD SMENUD R C/O MARTIN VOLK
568 COMPASS ROAD
OCEANSIDE, CALIFORNIA 92054
in
SUBMITTED BY I
CHRISTIAN WHEELER ENGINEERING 1 3980 HOME AVENUE
SAN DIEGO, CALIFORNIA 92105
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3980 Home Avenue + San Diego, CA 92105 + 619-550-1700 + FAX 619-550-1701
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CHR-ISTIAN WHEELEft
ENGINEEkINC
May 28, 2010
Richard Smenud
C/o Martin Volk
568 Compass Road
Oceanside, California 92054
CWE 2100122.01
SUBJECT: REPORT OF GEOTECHNICAL INVESTIGATION, PROPOSED BUENA VISTA
WAY RESIDENCE, 1099 BUENA VISTA WAY, CARLSBAD, CALIFORNIA
Dear Mr. Smenud:
In accordance with your request, and our proposal and agreement dated February 15, 2010, we have
completed a geotechnical investigation for the subject project. We are presenting herewith a report of our
findings and recommendations.
As encountered in our investigation, the site is underlain by potentially compressible fill/topsoil deposits
extending to a maximum depth of about 11/2 feet. In order to mitigate this condition, it is recommended that
the compressible materials be removed and replaced as compacted fill.
If you have questions after reviewing this report, please do not hesitate to contact our office. This
opportunity to be of professional service is sincerely appreciated.
Respectfully submitted,
CHRISTIAN WHEELER ENGINEERING
It Daniel B. Adler, RCE #36037
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OFC Charles H. Christian, RGE #00215
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CHC:CRB:DBA
Distribution: (6) Submitted
Curtis R. Burdett,
1 3980 Home Avenue + San 619-550-1700 + FAX 619-550-17
TABLE OF CONTENTS
PAGE
Introduction and Project Description ............................................................................................................... 1
Project Scope .......................................................................................................................................................... 2 Findings..................................................................................................................................................................3
SiteDescription................................................................................................................................................3
General Geology and Subsurface Conditions .............................................................................................3
Geologic Setting and Soil Description......................................................................................................3
ArtificialFill/Topsoil..............................................................................................................................3
OldParalic Deposits.................................................................................................................................3
Groundwater.................................................................................................................................................3
TectonicSetting............................................................................................................................................4
GeologicHazards..............................................................................................................................................4
SeismicDesign Factors ...............................................................................................................................4
Landslide Potential and Slope Stability.....................................................................................................5
Liquefaction..................................................................................................................................................5
Flooding.........................................................................................................................................................5
Tsunamis.......................................................................................................................................................5
Seiches............................................................................................................................................................5
Conclusions...........................................................................................................................................................6
Recommendations................................................................................................................................................ 6 Gradingand Earthwork..................................................................................................................................6
General...........................................................................................................................................................6
PregradeMeeting.........................................................................................................................................6
Observationof Grading..............................................................................................................................6
SitePreparation............................................................................................................................................7
RemovalLimits ............................................................................................................................................. 7 ImportedFill .............. ...................................................................................................................................7
Excavation Characteristics..........................................................................................................................7
Processingof Fill Areas...............................................................................................................................7
Compaction and Method of Filling ........................................................................................................... 7
SurfaceDrainage..........................................................................................................................................8
Foundations......................................................................................................................................................8
General...........................................................................................................................................................8
Dimensions...................................................................................................................................................8
BearingCapacity...........................................................................................................................................8
Foundation Reinforcement........................................................................................................................8
LateralLoad Resistance...............................................................................................................................9
ExpansiveCharacteristics...........................................................................................................................9
Settlement Characteristics...........................................................................................................................9
FoundationPlan Review.............................................................................................................................9
Foundation Excavation Observation........................................................................................................9
SolubleSulfates.................................................................................................................................................9
On-Grade Slabs..............................................................................................................................................10
InteriorFloor Slabs....................................................................................................................................10
Under-Slab Vapor Retarders....................................................................................................................10
Exterior Concrete Flatwork......................................................................................................................11
EarthRetaining Structures............................................................................................................................12
CWE 2100122.01
Proposed Buena Vista Way Residence
1099 Buena Vista Way, Carlsbad, California
TABLE OF CONTENTS (Continued)
PAGE
Foundations................................................................................................................................................12
PassivePressure..........................................................................................................................................12
ActivePressure...........................................................................................................................................12
Waterproofingand Subdrain .................................................................................................................... 12 Backfill.........................................................................................................................................................12
Limitations...........................................................................................................................................................12
Review, Observation and Testing................................................................................................................12
Uniformityof Conditions .............................................................................................................................13
Changein Scope ......... . .................................................................................................................................... 13 TimeLimitations............................................................................................................................................13
ProfessionalStandard .................................................................................................................................... 14 Client's Responsibility ................................... . ................................................................................................ 14 FieldExplorations..............................................................................................................................................14
LaboratoryTesting.............................................................................................................................................15
ATTACHMENTS
FIGURES
Figure 1 Site Vicinity Map, Follows Page 1
PLATES
Plates I Site Plan & Geologic Map
Plates 2-5 Test Pit Logs
Plate 6 Laboratory Test Results
Plate 7 Subdrain Detail
APPENDICES
Appendix A References
Appendix B Recommended Grading Specifications-General Provisions
CWE 2100122.01
Proposed Buena Vista Way Residence
1099 Buena Vista Way, Carlsbad, California
CHR-ISTIAN WHEELER
ENGINEEftING
REPORT OF GEOTECHNICAL INVESTIGATION
PROPOSED BUENA VISTA WAY RESIDENCE
1099 BUENA VISTA WAY
CARLSBAD. CALIFORNIA
INTRODUCTION AND PROJECT DESCRIPTION
This report presents the results of a geotechnical investigation performed for a propos
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residence to be located at 1099 Buena Vista Way, in the city of Carlsbad, California.
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Number 1 presents a site vicinity map showing the location of the property.
We understand that the proposed project will consist of the construction of a single-f
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structure, and an attached accessory dwelling unit. The residence will be a two-story, woo
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with an on-grade concrete floor slab; the accessory building will be a single-story struct
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concrete floor slab. We expect that both structures will be supported by conventional shal
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A retaining wall, less than four feet in height, is proposed along the eastern property line. G
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to consist of cuts and fills of less than about three to five feet from existing grades.
To assist in the preparation of this report, we were provided with a civil design plan of un
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April 27, 2010. A copy of said plan was used as the base for our Site Plan and Geotechnica
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included herewith as Plate Number 1.
This report has been prepared for the exclusive use of Richard Smenud and his design co
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application to the project described herein. Should the project be changed in any way, th
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should be submitted to Christian Wheeler Engineering for review to determine their conf
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recommendations and to determine whether any additional subsurface investigation, la
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and/or recommendations are warranted. Our professional services have been perfor
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obtained, and our recommendations prepared in accordance with generally accepted engineeri
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and practices. This warranty is in lieu of all other warranties, express or implied.
3980 Home Avenue + San Diego, CA 92105 + 619-550-1700 + FAX 619-550-1701
SITE VICINITY MAP
(Adapted from Thomas Brothers Maps)
PROPOSED BUENA VISTA WAY RESIDENCE
1099 BUENA VISTA WAY
CARLSBAD, CALIFORNIA
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C\XJE 2100122.01 May 2010 Figure 1
CWE 2100122.01 May 28, 2010 Page No. 2
PROJECT SCOPE
The scope of our preliminary investigation included: surface reconnaissance, subsurface exploration,
obtaining representative soil samples, laboratory testing, analysis of the field and laboratory data and review
of relevant geologic literature. Our scope of service did not include assessment of hazardous substance
contamination, recommendations to prevent floor slab moisture intrusion or the formation of mold within
the structure, evaluation or design of storm water infiltration facilities, or any other services not specifically
described in the scope of services presented below. More specifically, the intent of this investigation was to:
Explore the near-surface soil conditions of the site;
Evaluate, by laboratory tests and our past experience with similar soil types, the engineering
properties of the various strata that may influence the proposed construction, including
bearing capacities, expansive characteristics and settlement potential;
Describe the general geology at the site including possible geologic hazards that could have
an effect on the proposed construction, and provide seismic design parameters as required
by the 2007 edition of the California Building Code;
Address potential construction difficulties that may be encountered due to soil conditions,
groundwater or geologic hazards, and provide recommendations concerning these problems;
Develop soil engineering criteria for site preparation and grading;
Recommend an appropriate foundation system for the type of construction anticipated and
develop soil engineering design criteria for the recommended foundation design;
Present our professional opinions in this written report, which includes, in addition to our
conclusions and recommendations, a plot plan, exploration logs and a summary of the
I laboratory test results.
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CWE 2100122.01 May 28, 2010 Page No. 3
FINDINGS
SITE DESCRIPTION
The subject site is a nearly rectangular shaped parcel of land located at 1099 Buena Vista Way, in the city of
Carlsbad. The site is bounded on the south by Buena Vista Way, and is otherwise surrounded by single
family residential properties. The property is vacant at this time, but appears to once have supported a single-
family home and associated improvements. The relatively flat lot is about 67 feet wide and 150 feet deep.
Topographically, the site slopes gently to the northeast, with elevations ranging from about 741/2 feet mean
sea level (MSL) at the southwestern corner to elevation 70 feet MSL at the northeastern corner.
GENERAL GEOLOGY AND SUBSURFACE CONDITIONS
GEOLOGIC SETTING AND SOIL DESCRIPTION: The subject site is located within the Coastal Plains
Physiographic Province of San Diego County. Based on our subsurface explorations, and analysis of readily
available pertinent geologic literature, the area of the site investigated was found to be underlain by
undifferentiated artificial fill and topsoil, and old paralic deposits. Each of these units is discussed below in
order of increasing age.
ARTIFICIAL FILL/TOPSOIL: The site is underlain by a thin layer of undifferentiated fill/topsoil
extending, where exposed, to a maximum depth of about 11/2 feet below existing grade. The fill is the
result of recent grading associated with the demolition of the residential structure and associated
improvements that previously occupied the property. These materials consist of grayish-brown, dry to
damp, loose, silty sand (SM). The fill/topsoil materials were judged to possess a very low expansion
index (EI<20).
OLD PARALIC DEPOSITS (Qop): Old paralic deposits, locally referred as terrace deposits,
underlie the surficial soils. These deposits consist of orangish-brown, moist, medium dense to dense,
silty sands (SM). The formational soils were judged to possess a very low expansion index (EI<20).
GROUNDWATER: No groundwater was encountered in our subsurface explorations. However, it should be
recognized that minor groundwater seepage problems might occur after construction and landscaping at a site
even where none were present before construction. These are usually minor phenomena and are often the
result of an alteration in drainage patterns and/or an increase in irrigation water. Based on the anticipated
construction and landscaping, it is our opinion that any seepage problems that may occur will be minor in
CWE2100122.O1 May 28,2010 Page No. 4
extent. It is further our opinion that these problems can be most effectively corrected on an individual basis
if and when they occur.
TECTONIC SETTING: No active or potentially active faults are known to traverse the subject site.
However, it should be noted that much of Southern California, including the San Diego County area, is
characterized by a series of Quaternary-age fault zones that consist of several individual, en echelon faults that
generally strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults
within the zone) are classified as "active" according to the criteria of the California Division of Mines and
Geology. Active fault zones are those that have shown conclusive evidence of faulting during the Holocene
Epoch (the most recent 11,000 years). The Division of Mines and Geology used the term "potentially active"
on Earthquake Fault Zone maps until 1988 to refer to all Quaternary-age (last 1.6 million years) faults for the
purpose of evaluation for possible zonation in accordance with the Alquist-Priolo Earthquake Fault Zoning
Act and identified all Quaternary-age faults as "potentially active" except for certain faults that were
presumed to be inactive based on direct geologic evidence of inactivity during all of Holocene time or longer.
Some faults considered to be "potentially active" would be considered to be "active" but lack specific criteria
used by the State Geologist, such as .cuffident/y active and well-defined. Faults older than Quaternary-age are not
specifically defined in Special Publication 42, Fault Rupture Hazard Zones in California, published by the
California Division of Mines and Geology. However, it is generally accepted that faults showing no
movement during the Quaternary period may be considered to be "inactive".
The nearest active fault zone is the Newport-Inglewood Fault Zone located approximately 71/2 kilometers to
the west of the site. Other active fault zones in the region that could possibly affect the site include the Rose
Canyon Fault Zone to the southwest, the Palos Verde and Coronado Bank Fault Zones to the northwest; the
Elsinore, San Jacinto, and San Andreas Fault Zones to the northeast; and the Earthquake Valley Fault to the
east.
GEOLOGIC HAZARDS
SEISMIC DESIGN FACTORS: A likely geologic hazard to affect the site is ground shaking as a result of
movement along one of the major active fault zones mentioned above. The fault most likely to have a
significant effect on the site is the Newport-Inglewood Fault, located about 71/2 kilometers to the west of the
site. The seismic design factors applicable to the subject site are provided below. The seismic design factors
were determined in accordance with the 2007 California Building Code. The site coefficients and adjusted
maximum considered earthquake spectral response acceleration parameters are presented herein:
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CWE 2100122.01 May 28, 2010 Page No. 5
LI
Site Coordinates: Latitude
Longitude
33.1690
-117.3470
Site Class D
Site Coefficient Fa 1.0
Site Coefficient F 1.513
Spectral Response Acceleration at Short Periods S 1.293 g
Spectral Response Acceleration at 1 Second Period Si 0.487 g
Si5=FaSs 1.293g
SM1=FSi 0.737 g
SDs=2/3*S Is 0.862 g
SD1=2/3*SMI 0.491 g
Probable ground shaking levels at the site could range from slight to moderate, depending on such factors as
the magnitude of the seismic event and the distance to the epicenter. It is likely that the site will experience
the effects of at least one moderate to large earthquake during the life of the proposed improvements.
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LANDSLIDE POTENTIAL AND SLOPE STABILITY: As part of this investigation we reviewed the
publication, "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area" by Tan, 1995.
This reference is a comprehensive study that classifies San Diego County into areas of relative landslide
susceptibility. According to this publication, the majority of the site is located in Relative Landslide
Susceptibility Area 3-1, which is classified as "generally susceptible" to landsliding. Based on the lack of
significant slopes within the site vicinity, it is our opinion that the site potential for landsliding is negligible.
LIQUEFACTION: The near-surface soils encountered at the site possess a low risk potential for
liquefaction due to such factors.as soil density, grain-size distribution and the absence of a regional shallow
groundwater condition.
FLOODING: The site is located outside of the boundaries of both the 100-year and 500-year flood zones.
TSUNAMIS: Tsunamis are great sea waves produced by submarine earthquakes or volcanic eruptions. The site
is not subject to risk from tsunamis.
SEICHES: Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays or reservoirs.
The site will not be affected by seiches.
CWE 2100122.01 May 28, 2010 Page No. 6
CONCLUSIONS
It is our professional opinion and judgment that no geotechnical conditions exist on or in the general vicinity
of the subject property that would preclude the construction of the proposed residential project, provided the
recommendations presented herein are followed.
The main geotechnical condition affecting the subject project is the presence of a relatively thin layer of
potentially compressible fill and topsoil. Where encountered, these materials were noted to extend to a
maximum depth of about 1¼ feet below existing grade. These deposits are considered unsuitable, in their
present condition, for the support of settlement-sensitive improvements. In order to mitigate this condition,
ff it is recommended that these materials be removed and replaced as compacted fill.
The site is located in an area that is relatively free of geologic hazards that will have a significant effect on the EXI
proposed construction. The most likely geologic hazard that could affect the site is ground shaking due to
seismic activity along one of the regional active faults. However, construction in accordance with the
requirements of the most recent edition of the California Building Code and the local governmental agencies
should provide a level of life-safety suitable for the type of development proposed. a.
RECOMMENDATIONS
GRADING AND EARTHWORK
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GENERAL: All grading should conform to the guidelines presented in Appendix of the California
Building Code, the minimum requirements of the City of Carlsbad, and the Recommended Grading
Specifications and Special Provisions attached hereto as Appendix B, except where specifically superseded in
the text of this report.
PREGRADE MEETING: It is recommended that a pre-grade meeting, including the grading contractor
and a representative from Christian Wheeler Engineering be held, to discuss the recommendations of this
report and address any issues that may affect grading operations.
OBSERVATION OF GRADING: Continuous observation by the Geotechnical Consultant is essential
fi during the grading operation to confirm conditions anticipated by our investigation, to allow adjustments in
design criteria to reflect actual field conditions exposed, and to determine that the grading proceeds in general
I accordance with the recommendations contained herein.
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CWT_ 2100122.01 May 28, 2010 Page No. 7
SITE PREPARATION: Site preparation should begin with the removal of any vegetation and deleterious ' matter. Existing fill and topsoil materials underlying all areas to receive settlement-sensitive improvements
(including exterior flatwork) should be removed to expose competent formational deposits. Based on our
findings, the maximum estimated removal depth is about 11/2 feet below existing grade. However, deeper
removals may be necessary in areas of the site not investigated. Actual removal depths will be determined by
our project geologist, engineer or technician supervisor during site preparation. The bottoms of all
excavations should be approved by our representative prior to placing fills or constructing improvements,
and all areas to receive fill should be processed as described below in the "Processing of Fill Material" section
of this report.
REMOVAL LIMITS: Removal of unsuitable soils should extend at least five feet beyond the perimeter of
the proposed settlement-sensitive improvements, including exterior flatwork, or property lines, whichever is
less.
IMPORTED FILL: Imported fill may be necessary for the subject project. Imported fill should consist of
nondetrimentally expansive (Expansion Index less than 50) sands, silty sands and silty sands with clay.
Imported soils should be approved by this office prior to delivery to the site. A minimum 72-hour advance
notice is required to allow for laboratory testing required for proper evaluation.
EXCAVATION CHARACTERISTICS: It is anticipated that proposed excavations will be achieved
utilizing conventional grading equipment in good working order.
PROCESSING OF FILL AREAS: Prior to placing any new fill soils or constructing any new
improvements in areas that have been cleaned out and approved to receive fill, the exposed soils should be
scarified to a depth of 12 inches, moisture-conditioned, and compacted to at least 90 percent relative
compaction.
COMPACTION AND METHOD OF FILLING: All fill soils placed at the site should be compacted to a
relative compaction of at least 90 percent of maximum dry density as determined by ASTM Laboratory Test
D1557. Fills should be placed at or slightly above optimum moisture content, in lifts six to eight inches thick,
with each lift compacted by mechanical means. Fills should consist of approved earth material, free of trash or
I debris, roots, vegetation, or other materials determined to be unsuitable by our soil technicians or project
-M geologist. Fill material should be free of rocks or lumps of soil in excess of six inches in maximum dimension.
However, in the upper two feet of pad grade, no rocks or lumps of soil in excess of three inches should be
allowed.
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CWE 2100122.01 May 28, 2010 Page No. 8
SURFACE DRAINAGE: The drainage around the proposed improvements should be designed to collect
and direct surface water away from proposed improvements toward appropriate drainage facilities. Rain
gutters with downspouts that discharge runoff away from the structure and the top of slopes into controlled
drainage devices are recommended.
The ground around the proposed improvements should be graded so that surface water flows rapidly away
from the improvements without ponding. In general, we recommend that the ground adjacent to structures
be sloped away at a minimum gradient of two percent. Densely vegetated areas where runoff can be impaired
should have a minimum gradient of five percent for the first five feet from the structure.
FOUNDATIONS
GENERAL: Based on our findings, it is our opinion that the proposed improvements may be supported on
conventional shallow footings. The following recommendations are considered the minimum based on soil
conditions and are not intended to be lieu of structural considerations. All foundations should be designed by a
qualified structural engineer.
DIMENSIONS: Conventional footings supporting the main structure should have a minimum embedment
depth of 18 inches below lowest adjacent finish grade. Continuous and isolated footings should have a
minimum width of 15 inches and 24 inches, respectively. Footings to support the proposed accessory
building, and miscellaneous exterior improvements may be 12 inches deep and 12 inches wide. However,
footings for retaining walls should have a minimum depth and width of 18 inches and 24 inches, respectively.
BEARING CAPACITY: Continuous footings with minimum dimensions equal to 12 inches in depth and
width may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot. This value may
be increased by 600 pounds per square foot for each additional foot of embedment and 400 pounds per square
foot for each additional foot of width up to a maximum of 4,000 pounds per square foot. The beating value
may also be increased by one-third for combinations of temporary loads such as those due to wind or seismic
loads.
FOUNDATION REINFORCEMENT: The project structural engineer should provide foundation
reinforcement recommendations. However, based on the anticipated soil conditions, we recommend that the
minimum reinforcing for continuous footings should consist of at least one No. 5 bars positioned near the
bottom of the footing and one No. 5 bars positioned near the top of the footing.
CWE 2100122.01 May 28, 2010 Page No. 9
LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the
bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient
of friction between concrete and soil may be considered to be 0.35. The passive resistance may be considered
to be equal to an equivalent fluid weight of 350 pounds per cubic foot. This pressure may be increased one-
third for seismic loading. This assumes the footings are poured tight against undisturbed soil. If a combination
of the passive pressure and friction is used, the friction value should be reduced by one-third.
EXPANSIVE CHARACTERISTICS: The foundation soils were found to have a low expansive potential
(El < 50). The foundation recommendations presented in this report reflect this condition.
SETTLEMENT CHARACTERISTICS: The anticipated total and differential foundation settlement is
expected to be less than about 1 inch and 1 inch over 40 feet respectively, provided the recommendations
presented in this report are followed. It should be recognized that minor cracks normally occur in concrete
slabs and foundations due to shrinkage during curing or redistribution of stresses, therefore some cracks
should be anticipated. Such cracks are not necessarily an indication of excessive vertical movements.
FOUNDATION PLAN REVIEW: The foundation plans should be submitted to this office for review in
order to ascertain that the recommendations of this report have been implemented, and that no additional
recommendations are needed due to changes in the anticipated construction.
FOUNDATION EXCAVATION OBSERVATION: All footing excavations should be observed by
Christian Wheeler Engineering prior to placing reinforcing steel to determine if the foundation
recommendations presented herein are followed and that the foundation soils are as anticipated in the
preparation of this report. All footing excavations should be excavated neat, level, and square. All loose or
unsuitable material should be removed prior to the placement of concrete.
SOLUBLE SULFATES
The water soluble sulfate content of a randomly selected soil sample from the site was determined in
accordance with California Test Method 417. The results of this test indicate that the representative soil
sample had a soluble sulfate content of 0.075 percent. Soils with a soluble sulfate content of less than 0.1
Percent are considered to be negligible and no special recommendations are considered necessary for this
condition. Nevertheless, Type II modified Portland cement is recommended for concrete in contact with soil.
CWE 2100122.01 May 28, 2010 Page No. 10
ON-GRADE SLABS
INTERIOR FLOOR SLABS: When considered necessary due to loading conditions, the on-grade floor
slabs should be designed by a structural engineer. However, from a geotechnical perspective, we recommend
that the minimum floor slab thickness should be at least four inches (actual) and all floor slabs be reinforced
with at least No. 3 reinforcing bars placed at 18 inches on center each way. Slab reinforcement should be
supported on chairs such that the reinforcing bars are positioned at mid-height in the floor slab. The slab
reinforcement should extend into the perimeter grade beams or foundations at least six inches.
UNDER-SLAB VAPOR RETARDERS: Steps should be taken to minimize the transmission of moisture
vapor from the subsoil through the interior slabs where it can potentially damage the interior floor coverings.
Local industry standards typically include the placement of a vapor retarder, such as plastic, in a layer of
coarse sand placed directly beneath the concrete slab. In this case, two inches of sand and two inches of sand
are considered appropriate above and below the plastic, respectively. The vapor retarder should be at least 15-
mil plastic with sealed seams and should extend at least 12 inches down the sides of the interior and perimeter
footings. The sand should have a sand equivalent of at least 30, and contain less than 20% passing the
Number 100 sieve and less than 10% passing the Number 200 sieve.
Although the system described above has historically performed adequately, national standards for the
installation of vapor retarders below interior slabs are changing as evidenced in currently published standards
including ACT 302, "Guide to Concrete Floor and Slab Construction" and ASTM E1643, "Standard Practice
for Installation of Water Vapor Retarder Used in Contact with Earth or Granular Fill Under Concrete Slabs".
Rather than placing the vapor retarder between the two sand layers, both of these standards recommend
placing the sand capillary break layer onto the subgrade with a vapor retarder placed above the sand and the
concrete placed directly onto the vapor retarder. There are advantages and disadvantages to each of these
installation procedures.
An advantage to placing concrete directly onto a vapor retarder is that it eliminates the layer of sand between
the slab and vapor retarder. This layer of sand typically contains moisture prior to the placement of concrete
and can receive more moisture during the curing and construction processes. This moisture can be retained
in the sand layer for an extended period of time until the concrete moisture decreases to the point at which
the excess sand moisture is absorbed by the concrete and transmitted up through the slab. This process can
take many months depending upon the environmental conditions.
CWE2100122.O1 May 28,2010 Page No. 11
One disadvantage to placing concrete directly onto a vapor retarder is that removing the sand layer from
directly beneath the concrete restricts the ability of the concrete to lose moisture on both the top and bottom
surfaces during the initial curing period. Variations in the drying rate between the top and bottom surfaces
can result in increased concrete cracking, curling, and other finishing issues. The drying rate differences and
their potential side effects can be minimized, however, with suitable finishing and curing procedures.
Recognizing the stated benefits and limitations of these standard below-slab vapor retarder systems, the
owner and designer should select the system that they believe is most suitable for this project considering the
construction schedule and planned floor coverings. It should be understood that neither of the described
systems provides a "waterproof barrier". It should also be understood that slab concrete contains free water
and should be allowed to reach equilibrium in an environment similar to that anticipated in the completed
structure prior to installing floor coverings. We recommend that the flooring installer perform standard
moisture vapor emission tests prior to the installation of all moisture-sensitive floor coverings in accordance
with ASTM F1869 "Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete
Subfloor Using Anhydrous Calcium Chloride".
EXTERIOR CONCRETE FLATWORK. Exterior concrete slabs on grade should have a minimum
thickness of four inches and should be reinforced with at least No. 3 bars placed at 18 inches on center each
way (ocew). Driveway slabs should have a minimum thickness of 5 inches and be reinforced with at least No.
4 bars placed at 18 inches ocew. Driveway slabs should be provided with a 12-inch-deep thickened edge.
All slabs should be provided with weakened plane joints in accordance with the American Concrete Institute
(ACT) guidelines. Alternative patterns consistent with ACT guidelines can also be used.
A concrete mix with a 1-inch maximum aggregate size and a water/cement ratio of less than 0.6 is
recommended for exterior slabs. Lower water content will decrease the potential for shrinkage cracks.
Consideration should be given to using a concrete mix for the driveway that has a minimum compressive
strength of 3,000 pounds per square inch. This suggestion is meant to address early driveway use prior to full
concrete curing. Both coarse and fine aggregate should conform to the latest edition of the "Standard
Specifications for Public Works Construction" ('Greenbook").
Special attention should be paid to the method of concrete curing to reduce the potential for excessive
shrinkage and resultant random cracking. It should be recognized that minor cracks occur normally in
concrete slabs due to shrinkage. Some shrinkage cracks should be expected and are not necessarily and
indication of excessive movement or structural distress.
CWE 2100122.01 May 28, 2010 Page No. 12
EARTH RETAINING STRUCTURES
FOUNDATIONS: Foundations for proposed retaining walls should be constructed in accordance with the
recommendations for shallow foundations presented previously in this report.
PASSIVE PRESSURE: The passive pressure for the design of sliding resistance for the proposed retaining
wall footings may be considered to be 350 pounds per square foot per foot of depth. This pressure may be
increased one-third for seismic loading. The coefficient of friction for concrete to soil may be assumed to be
0.35 for the resistance to lateral movement. When combining frictional and passive resistance, the friction
should be reduced by one-third.
ACTIVE PRESSURE: The lateral soil pressure for the design of unrestrained earth retaining structures with
level backfill may be assumed to be equivalent to the pressure of a fluid weighing 38 pounds per cubic foot.
This pressure does not consider any other surcharge. If any are anticipated, this office should be contacted
for the necessary increase in soil pressure. These values are based on a drained, non-detrimentally expansive
(EI<50), granular backfill condition.
Proposed retaining walls associated with this project will be less than four feet in height. Therefore, it is our
opinion that seismic lateral earth pressures may not be considered for the design of said retaining walls.
WATERPROOFING AND SUBDRAIN: Waterproofing details should be provided by the project
architect. A suggested wall subdrain detail is provided on Plate No. 7. We recommend that the Geotechnical
Consultant observe all retaining wall subdrains to verify placement.
El BACKFILL: All backfill soils should be compacted to at least 90 percent relative compaction. Expansive or
clayey soils should not be used for backfill material. The wall should not be backfilled until the masonry has
reached an adequate strength.
LIMITATIONS
REVIEW, OBSERVATION AND TESTING
The recommendations presented in this report are contingent upon our review of final plans and
specifications. Such plans and specifications should be made available to the geotechnical engineer and
0
CWE2100122.O1 May 28,2010 Page No. 13
engineering geologist so that they may review and verify their compliance with this report and with the
California Building Code.
It is recommended that Christian Wheeler Engineering be retained to provide continuous soil engineering
services during the earthwork operations. This is to verify compliance with the design concepts,
specifications or recommendations and to allow design changes in the event that subsurface conditions differ
from those anticipated prior to start of construction.
UNIFORMITY OF CONDITIONS
The recommendations and opinions expressed in this report reflect our best estimate of the project
requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface
exploration locations and on the assumption that the soil conditions do not deviate appreciably from those
encountered. It should be recognized that the performance of the foundations and/or cut and fill slopes may
be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the
intermediate and unexplored areas. Any unusual conditions not covered in this report that may be
encountered during site development should be brought to the attention of the geotechnical engineer so that
he may make modifications if necessary.
CHANGE IN SCOPE
This office should be advised of any changes in the project scope or proposed site grading so that we may
determine if the recommendations contained herein are appropriate. This should be verified in writing or
modified by a written addendum.
TIME LIMITATIONS
The findings of this report are valid as of this date. Changes in the condition of a property can, however,
occur with the passage of time, whether they be due to natural processes or the work of man on this or
adjacent properties. In addition, changes in the Standards-of-Practice and/or Government Codes may occur.
Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our
control. Therefore, this report should not be relied upon after a period of two years without a review by us
verifying the suitability of the conclusions and recommendations.
El
9
CWE 2100122.01 May 28, 2010 Page No. 14
PROFESSIONAL STANDARD
In the performance of our professional services, we comply with that level of care and skill ordinarily
exercised by members of our profession currently practicing under similar conditions and in the same locality.
The client recognizes that subsurface conditions may vary from those encountered at the locations where our
borings, surveys, and explorations are made, and that our data, interpretations, and recommendations be
based solely on the information obtained by us. We will be responsible for those data, interpretations, and
recommendations, but shall not be responsible for the interpretations by others of the information
developed. Our services consist of professional consultation and observation only, and no warranty of any
kind whatsoever, express or implied, is made or intended in connection with the work performed or to be
performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written
reports or findings.
CLIENT'S RESPONSIBILITY
It is the responsibility of the client, or his representatives, to ensure that the information and
recommendations contained herein are brought to the attention of the structural engineer and architect for
the project and incorporated into the project's plans and specifications. It is further their responsibility to
take the necessary measures to insure that the contractor and his subcontractors carry out such
recommendations during construction.
FIELD EXPLORATIONS
Four subsurface explorations were made on May 5, 2010 at the locations indicated on the attached Plate
Number 1. These explorations consisted of hand-dug test pits. The fieldwork was conducted under the
observation of our engineering geology personnel.
The explorations were carefully logged when made. The logs are presented on the following Plate Numbers
2 through 5. The soils are described in accordance with the Unified Soils Classification System. In addition,
a verbal textural description, the wet color, the apparent moisture and the density or consistency are provided.
The density of granular soils is given as very loose, loose, medium dense, dense or very dense. The
consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff, or hard.
Relatively undisturbed chunk samples and bulk samples of the encountered earth materials were collected and
transported to our laboratory for testing.
CWE 2100122.01 May 28, 2010 Page No. 15
LABORATORY TESTING
Laboratory tests were performed in accordance with the generally accepted American Society for Testing and
Materials (ASTM) test methods or suggested procedures. A brief description of the tests performed is
presented below:
CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The
final soil classifications are in accordance with the Unified Soil Classification System.
MOISTURE-DENSITY: In-place moisture contents and dry densities of selected soil samples were
determined in accordance with ASTM D 1188. The test results are summarized in the pit logs.
MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST: The maximum
dry density and optimum moisture content of a selected soil sample were determined in accordance with
ASTM D 1557, Method A. The results of this test are presented on Plate Number 6.
DIRECT SHEAR TEST: A direct shear test was performed on a selected sample of the
on-site soils in accordance with ASTM D 3080. The results of this test are presented on Plate
Number 6.
f) SOLUBLE SULFATES: The soluble sulfate content of a selected soil sample was determined in
accordance with California Test Method 417. The test results are presented on Plate Number 6.
CWE LEGEND
e OLD PARALIC DEPOSITS
JP-4
APPROXiMATE TEST PIT LOCATION
ly. I T
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41 ••r \ / '/ . -T
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to
20.00'
- Qop - I 1-'
01 53/' P-2
L_J - U b .-i3. ./ --:; • / .
..
/ . . 0033'42" E / 150.00'
jvrjq V CIVIL P -
'-1.17.10
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.
;.1.-7 ,-,,jr IA. flrA.-..IAIAJ . .- .. . ... •.- ..:j;............
0 16' 32'
SCALE: 1" = 16'
SITE PLAN AND GEOTECHNICAL MAP
PROPOSED BUENA VISTA WAY RESIDENCE
1099 Buena Vista Way, Carlsbad, California
DATE: MAY 2010 REPORT NO.: 2100122.01
BY: DA/TSW/SCC PLATE NO.: I
CHRISTIAN WHEELER
ENGINEERING
LOG OF TEST PIT P-i Sample Type and Laboratory Test Legend
Cal Modified California Sampler CK Chunk Sample
SPTStandard Penetration Test DR Density Ring Date Excavated: 5/5/10 Equipment Hand Tools ST Shelby Tube
Logged by: DF Bucket Size: N/A MD Maximum Density DS Direct Shear
SO4 Soluble Sulfates Con Consolidation Existing Elevation: 71 feet Drive Weight N/A SA Sieve Analysis El Expansion Index
HA Hydrometer R-Val Resistance Value Proposed Elevation: 74 feet Depth to Water: N/A SE Sand Equivalent ChI Soluble Chlorides PT Plasdciry Index Res H&Reissrivitv
z 0 0 SUMMARY OF SUBSURFACE CONDITIONS TaT t-
z tI z — 0
rA (based on Unified Soil Classification System)
z - 0
0 71 SM Artificial Fill/Topsoil (Oa Grayish-brown, damp, — — —
- loose, SILTY SAND, fine to medium-grained, porous, with rootlets.
1"70
SM Old Paralic Deposits (Oop): Orangish-brown, moist, — - -
- medium dense, SILTY SAND, fine to medium-grained, slightly
2 -69 weathered to 3 feet.
CK 4.9 104.8
3 —
-
At 3 feet becomes dense.
4 — —67
T.
CK 6.6 103.9
5 -66
Test Pit terminated at 5 feet. — — — — —
-
- No water or seepage encountered.
6 -65
7 -64
Symbol Legend
! Groundwater
PROPOSED BUENA VISTA WAY RESIDENCE
I
1099 Buena Vista Way, Carlsbad, California
Apparent Seepage CHR-ISTIAN WHEELEK
I BY: DJF DATE: May 2010
* No Sample Recovery E N C I N E E R. I N G
** Nonrepresentative Blow
JOB 2100122
I
I
PLATE NO.: 2
Count (rocks present)
LOG OF TEST PIT P-2 Sample Type and Laboratory Test Legend
Cal Modified California Sampler CK Chunk Sample
Standard Penetration Test DR Density Ring
Shelby Tube
SPT Date Excavated: 5/5/10 Equipment Hand Tools ST
Logged by: DF Bucket Size: N/A MD Maximum Density DS Direct Shear
SO4 Soluble Sulfates Con Consolidation
Existing Elevation: 73.5 feet Drive Weight N/A SA Sieve Analysis El Expansion Index
HA Hydrometer R-Val Resistance Value
Proposed Elevation: 74 feet Depth to Water: N/A SE Sand Equivalent ChI Soluble Chlorides
Pt Plascitv Index Res pH & Resisuvitv
z o Z
2 Z
2 SUMMARY OF SUBSURFACE CONDITIONS
(based on Unified Soil Classification System)
r i r r
rA
0 73.5 SM Artificial Fill/Topsoil (Oafl: Grayish-brown, damp,
-
loose, SILTY SAND, fine to medium-grained, porous, with rootlets.
I -72.5
Ml
. SM Old Paralic Deposits (OOP): Orangish-brown, moist, -
medium dense to dense, SILTY SAND, fine to medium-grained,
2 -71.5 mottled, slightly weathered to 2 feet.
- CK 7.4 121.4
70.5
- . Test Pit terminated at 3.5 feet.
No water or seepage encountered.
-69.5
-68.5
6 --67.5
Symbol Le-end
PROPOSED BUENA VISTA WAY RESIDENCE
Groundwater
AN
1099 Buena Vista Way, Carlsbad, California
Apparent Seepage CHRISTIAN WHEELER * No Sample Recovery ENGINEERING
** Nonrepresentative Blow BY: DJF DATE: May 2010
Count (rocks present
JOB NO.: 2100122 PLATE NO.: 3
I
LOG OF TEST PIT P-3 Sample Type and Laboratory Test Legend
Cal Modified California Sampler CK Chunk Sample SPTStandard Penetration Test DR Density Ring Date Excavated: 5/5/10 Equipment Hand Tools ST Shelby Tube
Logged by: DF Bucket Size: N/A MD Maximum Density DS Direct Shear
SO4 Soluble Sulfates Con Consolidation
Existing Elevation: 73 feet Drive Weight N/A SA Sieve Analysis El Expansion Index
F-IA Hydrometer R-Val Resistance Value
Proposed Elevation: 74 feet Depth to Water: N/A SE Sand Equivalent ChI Soluble Chlorides
P1 Plasis'citv Index Res pH&Resistivin
Z
Z
Z 0
SUMMARY OF SUBSURFACE CONDITIONS Z Z I-
(based on on Unified Soil Classification System) C'
U tI Z n. Cl- Cl)
Cl)
0 73 SM Artificial Fill/Topsoil (Oaf): Grayish-brown, damp, — — — — -
- loose, SILTY SAND, fine to medium-grained, porous, with rootlets.
1 -72 SM Old Paralic Deposits (Oop): Orangish-brown, moist, -
- medium dense, SILTY SAND, fine to medium-grained,
- - moderately weathered to 2 feet.
2 — CK 40 113.8
3 -70
Test Pit terminated at 3 feet. -
- No water or seepage encountered.
4—-69
5— -68
6 -67
7 16
Symbol Legend
PROPOSED BUENA VISTA WAY RESIDENCE I ! Groundwater 1099 Buena Vista Way, Carlsbad, California
7
Apparent Seepage CHPJSTIAN WHEELER.
BY: DJF I DATE: May 2010
* No Sample Recovery F N G I N E E P. I N C
Nonrepresentative Blow
JOB NO.: 2100122 I PLATE NO.: 4
Count (rocks present)
LOG OF TEST PIT P-4 Sample Type and Laboratory Test Legend
Cal Modified California Sampler CK Chunk Sample
SPTSandard Penetration Test DR Density Ring Date Excavated: 5/5/10 Equipment Hand Tools ST Shelby Tube
P Logged by: DF Bucket Size: N/A bID Maximum Density DS Direct Shear SO4 Soluble Sulfates Con Consolidation Existing Elevation: 74 feet Drive Weight N/A SA Sieve Analysis El Expansion Index
HA l-lsurometer R-Val Resistance Value Proposed Elevation: 74 feet Depth to Water: N/A SE Sand Equivalent Chl Soluble Chlorides
P1 °lasncttv Index Res pH & Resistivity
z z
0 co
SUMMARY OF SUBSURFACE CONDITIONS
I (based on Unified Soil Classification System)
- t_, o
0 74 SM Artificial Fill/Topsoil (Oafl: Grayish-brown, damp, MD loose, SILTY SAND, fine to medium-grained, porous, with rootlets. DS
-- SO4
173
- SM Old Paralic Deposits (Oop): Orangish-brown, moist, -
medium dense to dense, SILTY SAND, fine to medium-grained.
2 - 72
- - CK 5.3 113.1
3=j
4 -70
- Test Pit terminated at 4 feet. -
No water or seepage encountered.
5- -69
6—-68
Symbol Legend
PROPOSED BUENA VISTA WAY RESIDENCE
Groundwater
1099 Buena Vista Way, Carlsbad, California
Apparent Seepage CHRISTIAN WHEELER.
BY: DJF 2010
* No Sample Recovery ENGINEER.ING
** Nonrepresentative Blow DATE: May
JOB NO.: 2100122 PLATE NO.: 5
Count crocks present)
LABORATORY TEST RESULTS
PROPOSED BUENA VISTA WAY RESIDENCE
1099 BUENA VISTA WAY
OCENASIDE, CALIFORNIA
MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT (ASTM D1557)
Sample Location Test Pit P-4 @ 011/2
Sample Description Gray Brown Silty Sand (SM)
Maximum Density 126.2 pcf
Optimum Moisture 8.2%
DIRECT SHEAR (ASTM D3080)
Sample Location Test Pit P-4 @ 0-11/2'
Sample Type Remolded to 90 %
Friction Angle 310
Cohesion 100 psf
SOLUBLE SULFATES (CALIFORNIA TEST 417)
Sample Location
Soluble Sulfate
Test Pit P-4 @ 0-11/2'
0.075 % (SO4)
CWE 2100122.01 May 28, 2010 Plate No. 6
CHPJSTIAN WHEELER
ENG IN EER.ING
Ii
DRAINAGE SWALE (BY OTHERS)
12' MIN.
WATERPROOFING (BY OTHERS)
3/4' CRUSHED
ROCK BACKFILL
FILTER FABRIC BETWEEN
ROCK AND SOIL
(MIRAFI NON OR EQUIVALENT)
TOP OF GROUND
OR CONCRETE SLAB
4-INCH MIN. PERFORATED PIPE
(PVC SDR 35 OR SCHEDULE 40)
1•. 12" MIN .. .
. •
. . .. .4 .t . ••• • ..
44
1•
.4
I
NOTES
I. COMPOSITE DRAINAGE MATS, SUCH AS MIRADRAIN, ARE CONSIDERED A SUITABLE ALTERNATIVE
AND SHOULD BE INSTALLED IN ACCORDANCE WITH MANUFACTURER'S SPECIFICATIONS.
2. RETAINING WALL SUBDRAIN OUTLETS SHOULD BE COORDINATED BY THE PROJECT CIVIL ENGINEER.
SUBTERRANEAN RETAINING WALLS MAY REQUIRE A SUMP AND PUMP SYSTEM.
NO SCALE
BUENA VISTA WAY RESIDENCE
1099 BUENA VISTA 'WAY
CARSLBAD, CALIFORNIA
BY: SCC DATE: MAY 28, 2010
RETAINING WALL SUBDRAIN
DETAIL
REPORT NO.: 210012201 I PLATE NO.: 7
CWE 2100122.01 May 28, 2010 Appendix A, Page A-I
REFERENCES
Tan, S.S., 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San
Diego County, California, California Division of Mines and Geology Open-File Report 95-03.
Unites States Geologic Survey, Seismic Design Values for Buildings, Java Ground Motion Calculator
Version 5.0.9a.
CWE 2100122.01 May 28, 2010 Appendix B, Page B-I
RECOMMENDED GRADING SPECIFICATIONS - GENERAL PROVISIONS
PROPOSED BUENA VISTA WAY RESIDENCE
1099 BUENA VISTA WAY
OCEANSIDE, CALIFORNIA
GENERAL INTENT
The intent of these specifications is to establish procedures for clearing, compacting natural ground,
preparing areas to be filled, and placing and compacting fill soils to the lines and grades shown on the
accepted plans. The recommendations contained in the preliminary geotechnical investigation report and/or
the attached Special Provisions are a part of the Recommended Grading Specifications and shall supersede
the provisions contained hereinafter in the case of conflict. These specifications shall only be used in
conjunction with the geotechnical report for which they are a part. No deviation from these specifications
will be allowed, except where specified in the geotechnical report or in other written communication signed
by the Geotechnical Engineer.
OBSERVATION AND TESTING
Christian Wheeler Engineering shall be retained as the Geotechnical Engineer to observe and test the
earthwork in accordance with these specifications. It will be necessary that the Geotechnical Engineer or his
representative provide adequate observation so that he may provide his opinion as to whether or not the
work was accomplished as specified. It shall be the responsibility of the contractor to assist the Geotechnical
Engineer and to keep him apprised of work schedules, changes and new information and data so that he may
provide these opinions. In the event that any unusual conditions not covered by the special provisions or
preliminary geotechnical report are encountered during the grading operations, the Geotechnical Engineer
shall be contacted for further recommendations.
If, in the opinion of the Geotechnical Engineer, substandard conditions are encountered, such as
questionable or unsuitable soil, unacceptable moisture content, inadequate compaction, adverse weather, etc.,
construction should be stopped until the conditions are remedied or corrected or he shall recommend
rejection of this work.
Tests used to determine the degree of compaction should be performed in accordance with the following
American Society for Testing and Materials test methods:
CWE 2100122.01 May 28, 2010 Appendix B, Page B-2
Maximum Density & Optimum Moisture Content - ASTM D-1557
Density of Soil In-Place - ASTM D-1 556 or ASTM D-6938
All densities shall be expressed in terms of Relative Compaction as determined by the foregoing ASTM
testing procedures.
PREPARATION OF AREAS TO RECEIVE FILL
All vegetation, brush and debris derived from clearing operations shall be removed, and legally disposed of.
All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris.
After clearing or benching the natural ground, the areas to be filled shall be scarified to a depth of 6 inches,
brought to the proper moisture content, compacted and tested for the specified minimum degree of
compaction. All loose soils in excess of 6 inches thick should be removed to firm natural ground which is
defined as natural soil which possesses an in-situ density of at least 90 percent of its maximum dry density.
When the slope of the natural ground receiving fill exceeds 20 percent (5 horizontal units to I vertical unit),
the original ground shall be stepped or benched. Benches shall be cut to a firm competent formational soil.
The lower bench shall be at least 10 feet wide or 1-1/2 times the equipment width, whichever is greater, and
shall be sloped back into the hillside at a gradient of not less than two (2) percent. All other benches should
be at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as
specified herein for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when
considered necessary by the Geotechnical Engineer.
Any abandoned buried structures encountered during grading operations must be totally removed. All
underground utilities to be abandoned beneath any proposed structure should be removed from within 10
feet of the structure and properly capped off. The resulting depressions from the above described procedure
should be backfilled with acceptable soil that is compacted to the requirements of the Geotechnical Engineer.
This includes, but is not limited to, septic tanks, fuel tanks, sewer lines or leach lines, storm drains and water
lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the
Geotechnical Engineer so that he may determine if any special recommendation will be necessary.
All water wells which will be abandoned should be backflhled and capped in accordance to the requirements
set forth by the Geotechnical Engineer. The top of the cap should be at least 4 feet below finish grade or 3
CWE 2100122.01 May 28, 2010 Appendix B, Page B-3
feet below the bottom of footing whichever is greater. The type of cap will depend on the diameter of the
well and should be determined by the Geotechnical Engineer and/or a qualified Structural Engineer.
FILL MATERIAL
Materials to be placed in the fill shall be approved by the Geotechnical Engineer and shall be free of
vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill
the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered
in the geotechnical report or Special Provisions. Expansive soils, soils of poor gradation, or soils with low
strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only
with the explicit consent of the Geotechnical Engineer. Any import material shall be approved by the
Geotechnical Engineer before being brought to the site.
PLACING AND COMPACTION OF FILL
Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in
compacted thickness. Each layer shall have a uniform moisture content in the range that will allow the
compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be
uniformly compacted to the specified minimum degree of compaction with equipment of adequate size to
economically compact the layer. Compaction equipment should either be specifically designed for soil
compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either
the Special Provisions or the recommendations contained in the preliminary geotechnical investigation
report.
When the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be
carefully filled with soil such that the minimum degree of compaction recommended in the Special
Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non-
structural fills is discussed in the geotechnical report, when applicable.
Field observation and compaction tests to estimate the degree of compaction of the fill will be taken by the
Geotechnical Engineer or his representative. The location and frequency of the tests shall be at the
Geotechnical Engineer's discretion. When the compaction test indicates that a particular layer is at less than
the required degree of compaction, the layer shall be reworked to the satisfaction of the Geotechnical
Engineer and until the desired relative compaction has been obtained.
LE
CWE 2100122.01 May 28, 2010 Appendix B, Page B-4
Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction by
sheeps foot roller shall be at vertical intervals of not greater than four feet. In addition, fill slopes at a ratio of
two horizontal to one vertical or flatter, should be trackrolled. Steeper fill slopes shall be over-built and cut-
back to finish contours after the slope has been constructed. Slope compaction operations shall result in all
fill material six or more inches inward from the finished face of the slope having a relative compaction of at
least 90 percent of maximum dry density or the degree of compaction specified in the Special Provisions
section of this specification. The compaction operation on the slopes shall be continued until the
Geotechnical Engineer is of the opinion that the slopes will be surficially stable.
Density tests in the slopes will be made by the Geotechnical Engineer during construction of the slopes to
determine if the required compaction is being achieved. Where failing tests occur or other field problems
arise, the Contractor will be notified that day of such conditions by written communication from the
Geotechnical Engineer or his representative in the form of a daily field report.
If the method of achieving the required slope compaction selected by the Contractor fails to produce the
necessary results, the Contractor shall rework or rebuild such slopes until the required degree of compaction
is obtained, at no cost to the Owner or Geotechnical Engineer.
CUT SLOPES
The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during
the grading operations at intervals determined at his discretion. If any conditions not anticipated in the
preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse
nature, unfavorably inclined bedding, joints or fault planes are encountered during grading, these conditions
shall be analyzed by the Engineering Geologist and Geotechnical Engineer to determine if mitigating
measures are necessary.
Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than
that allowed by the ordinances of the controlling governmental agency.
ENGINEERING OBSERVATION
Field observation by the Geotechnical Engineer or his representative shall be made during the filling and
compaction operations so that he can express his opinion regarding the conformance of the grading with
acceptable standards of practice. Neither the presence of the Geotechnical Engineer or his representative or
I. I r
CWE 2100122.01 May 28, 2010 Appendix B, Page B-5
the observation and testing shall release the Grading Contractor from his duty to compact all fill material to
the specified degree of compaction.
SEASON LIMITS
Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain,
filling operations shall not be resumed until the proper moisture content and density of the fill materials can
be achieved. Damaged site conditions resulting from weather or acts of God shall be repaired before
acceptance of work.
RECOMMENDED GRADING SPECIFICATIONS - SPECIAL PROVISIONS
RELATIVE COMPACTION: The minimum degree of compaction to be obtained in compacted natural
ground, compacted fill, and compacted backfill shall be at least 90 percent. For street and parking lot
subgrade, the upper six inches should be compacted to at least 95 percent relative compaction.
EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of
50 or greater when tested in accordance with ASTM D 4829.
OVERSIZED MATERIAL: Oversized fill material is generally defined herein as rocks or lumps of soil
over 6 inches in diameter. Oversized materials should not be placed in fill unless recommendations of
placement of such material is provided by the Geotechnical Engineer. At least 40 percent of the fill soils
shall pass through a No. 4 U.S. Standard Sieve.
TRANSITION LOTS: Where transitions between cut and fill occur within the proposed building pad, the
cut portion should be undercut a minimum of one foot below the base of the proposed footings and
recompacted as structural backfill. In certain cases that would be addressed in the geotechnical report,
special footing reinforcement or a combination of special footing reinforcement and undercutting may be
required.
JAN 20 2011
ENGINEERING
DEPARTMENT
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