HomeMy WebLinkAboutCT 04-06; Palomar Pointe; Geotechnical Engineering Investigation; 2001-11-05Geotechnical Engineering Investigation
Office Development
1815 Aston Avenue
Carlsbacl, California
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ENGINEERING
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SOILS AND GEOTECHNICAL CONSULTANTS
Geotechnical Engineering Investigation
Office Development
1815 Aston Avenue
Carlsbad, California
Prepared For:
Lanikai IVIanagement Corporation
1815 Aston, Suite 106
Carlsbad, California 92008
Attn.: Mr. Larry Jett
Project Number 9623-01
November 5, 2001
TABLE OF CONTENTS
Section Page
1.0 Project Description 2
2.0 Site Description 2
3.0 Site Exploration 2
4.0 Laboratory Tests
4.1 Field Moisture Content 3
4.2 Maximum Density Tests 3
4.3 Expansion Index Tests 4
4.4 Atterberg Limits 4
4.5 Sulfate Tests 4
4.6 Direct Shear Tests 4
4.7 Consolidation Tests 4
5.0 Seismicity Evaluation 4
6.0 Liquefaction Evaluation 5
7.0 Conclusions and Recommendations
7.1 Site Grading Recommendations 6
7.1.1 Removal and Recompaction Recommendations 6
7.1.2 Fill Blanket Recommendations 7
7.2 Shrinkage and Subsidence 8
7.3 Temporary Excavations 8
7.4 Foundation Design 8
7.5 Settlement Analysis 9
7.6 Lateral Resistance 9
7.7 Retaining Wall Design Parameters 10
7.8 Slab Design 10
7.9 Pavement Section Design 11
7.10 Utility Trench and Excavation Backfill 12
7.11 Corrosion Design Criteria 12
8.0 Closure 12
NorCal Engineering
Soils and Geotechnical Consultants
10641 Humbolt Street Los Alamitos, CA 90720
(562) 799-9469 Fax (562) 799-9459
November 5, 2001 Project Number 9623-01
Lanikai Management Corporation
1815 Aston, Suite 106
Carlsbad, California 92008
Attn.: Mr. Larry Jett
RE: Geotechnical Engineering Investigation - Proposed Office Development
(+14 Acre Parcel) - Located East of 1815 Aston Avenue, in the City of
Carlsbad, California
Dear Mr. Jett:
Pursuant to your request, this firm has performed a Geotechnical Engineering
Investigation for the proposed commercial development at the above referenced project.
The purpose of this investigation is to evaluate the subsurface conditions of the subject
site and to provide recommendations for the proposed self storage development.
The scope of work included the following: 1) site reconnaissance; 2) subsurface
geotechnical exploration and sampling; 3) laboratory testing; 4) engineering analysis of
field and laboratory data; and 5) preparation of a geotechnical engineering report. It is
the opinion of this firm that the proposed development is feasible from a geotechnical
standpoint provided that the recommendations presented in this report are followed in
the design and construction of the project.
November 5, 2001 Project Number 9623-01
Page 2
1.0 Project Description
It is proposed to construct an office development as shown on the site plan. Other
improvements will consist of property line screen walls, concrete and asphaltic
pavement and landscaping. The buildings will be supported by a conventional slab-on-
grade foundation system with perimeter-spread footings and isolated interior footings. It
is assumed that the proposed grading for the development will include minor cut and fill
procedures. Final building plans shall be reviewed by this firm prior to submittal for city
approval to determine the need for any additional study and revised recommendations
pertinent to the proposed development, if necessary.
2.0 Site Description
The approximately 14 acre subject site consists of an irregular shaped parcel located
easterly of College Avenue and southerly of Aston Avenue, in the city of Carlsbad. The
parcel is elongated in a east to west direction with topography of the property
descending from west to east. The property is currently undeveloped land which
contains minor scattered debris and small stockpiles of fill, concrete and debris in the
southeasterly portion. Outcroppings of bedrock are located throughout the site.
Moderate to heavy vegetation was noted throughout the parcel.
3.0 Site Exploration
The investigation consisted of the placement of seven (7) subsurface exploratory
trenches by a backhoe to a maximum depth of 9 feet below current ground elevations.
The explorations were visually classified and logged by a field engineer and geologist
with locations of the subsurface explorations shown on the attached Site Plan. The
depth of the excavation was limited due to the hardness of the bedrock.
The exploratory trenches revealed the existing earth materials to consist of a disturbed
top soil/fill and natural soil/bedrock. A detailed description of the subsurface conditions
are listed on the excavation logs in Appendix A.
t
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 3
Disturbed Top/Fill Soils: A disturbed/fill soil classifying as a brown, silty CLAY to
clayey SAND was encountered across the site to a depth of 6 inches. These soils
were noted to be firm to medium dense and dry due to past weathering.
Natural: An undisturbed native soil classifying as a brown, silty CLAY bedrock
material was encountered beneath the upper surface soils. These native soils were
observed to be stiff to very hard and dry to moist. The high density of these soils
limited the depths of our excavations.
The overall engineering characteristics of the earth material were relatively uniform with
each excavation. No groundwater was encountered to the depth of our trenches and no
caving occurred; however, the soils in portions of the site have contained water in the
upper +2 feet during the rainy season.
4.0 Laboratory Tests
Relatively undisturbed samples of the subsurface soils were obtained to perform
laboratory testing and analysis for direct shear, consolidation tests, and to determine in-
place moisture/densities. These relatively undisturbed ring samples were obtained by
driving a thin-walled steel sampler lined with one inch long brass rings with an inside
diameter of 2.42 inches into the undisturbed soils.
Bulk bag samples were obtained in the upper soils for expansion index tests and
maximum density tests. Wall loadings on the order of 4,000 Ibs./lin.ft. and maximum
compression loads on the order of 100 kips were utilized for testing and design
purposes. All test results are included in Appendix B, unless otherwise noted.
4.1 Field moisture content (ASTM:D 2216) and the dry density of the ring samples were
determined in the laboratory. This data is listed on the logs of explorations.
4.2 Maximum density tests (ASTM: D-1557-00) were performed on typical samples of the
upper soils. Results of these tests are shown on Table I.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 4
4.3 Expansion index tests in accordance with the Uniform Building Code Standard No. 29-
2 were performed on remolded samples of the upper soils. Results of these tests are
provided on Table II.
4.4 Atterberg Limits (ASTM: D 4318-84) consisting of liquid limit, plastic limit and plasticity
index were performed on representative soil samples. Results are shown on Table III.
4.5 Sulfate tests to determine the potential corrosive effects of soils on concrete were
performed in the laboratory. Test results are provided on Table IV.
4.6 Direct shear tests (ASTM: D-3080) were performed on undisturbed and disturbed
samples of the subsurface soils. The test is performed under saturated conditions at
loads of 500 Ibs./sq.ft., 1,000 Ibs./sq.ft., and 2,000 Ibs./sq.ft. with results shown on Plate
A.
4.7 Consolidation tests (ASTM: D-2435) were performed on undisturbed samples to
determine the differential and total settlement which may be anticipated based upon the
proposed loads. Water was added to the samples at a surcharge of one KSF and the
settlement curves are plotted on Plate B.
5.0 Seismicity Evaluation
There are no known active or potentially active faults trending toward or through the site.
The proposed development lies outside of any Alquist Priolo Special Studies Zone and
the potential for damage due to direct fault rupture is considered very remote. The site
is located in an area of high regional seismicity and a maximum credible horizontal
ground acceleration of 0.43g may occur from a Magnitude 6.9 earthquake along the
Rose Canyon fault zone, which is located approximately 6 miles away.
Ground shaking originating from earthquakes along other active faults in the region is
expected to induce lower horizontal accelerations due to smaller anticipated
earthquakes and/or greater distances to other faults.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 5
The following earthquake design parameters are based upon the 1997 Uniform Building
Code (UBC) for a Seismic Zone 4 with a Z factor of 0.40 and a Soil Profile Type of So, a
stiff soii profile.
Earthquake Fault Rose Canvon
1. Distance to Fault 10 km
2. Seismic Source Type B
3. Seismic Coefficient = Ca (0.44) Na
4. Seismic Coefficient = Cv (0.64) Nv
5. Near-Source Factor Na 1.0
6. Near-Source Factor Nv 1.0
6.0 Liquefaction Evaluation
The site is expected to experience ground shaking and earthquake activity that is typical
of Southern California area. It is during severe ground shaking that loose, granular soils
below the groundwater table can liquefy. Our analysis indicates the potential for
liquefaction at this site is considered to be very low due to the near surface bedrock
conditions at the subject site. Thus, the design of the proposed construction in
conformance with the latest Building Code provisions for earthquake design is expected
to provide mitigation of ground shaking hazards that are typical to Southern California.
7.0 Conclusions and Recommendations
Based upon our evaluations, the proposed development is acceptable from a
geotechnical engineering standpoint. By following the recommendations and guidelines
set forth in our report, the structures will be safe from excessive settlements under the
anticipated design loadings and conditions. The proposed development shall meet all
requirements of the City Building Ordinance and will not impose any adverse effect on
existing adjacent structures.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 6
The following recommendations are based upon geotechnical conditions encountered in
our field investigation and laboratory data. Therefore, these surface and subsurface
conditions could vary across the site. Variations in these conditions may not become
evident until the commencement of grading operations and any unusual conditions
which may be encountered in the course of the project development may require the
need for additional study and revised recommendations.
It is recommended that site inspections be performed by a representative of this firm
during all grading and construction of the deveiopment to verify the findings and
recommendations documented in this report. The following sections present a
discussion of geotechnical related requirements for specific design recommendations of
different aspects of the project.
7.1 Site Gradinq Recommendations
Any vegetation shall be removed and hauled from proposed grading areas prior to the
start of grading operations. Existing vegetation shall not be mixed or disced into the
soils. Any removed soils may be reutilized as compacted fill once any deleterious
material or oversized materials (in excess of eight inches) is removed. Grading
operations shall be performed in accordance with the attached "Specifications for
Placement of Compacted Fill".
7.1.1 Removal and Recompaction Recommendations
All disturbed/low density soils (6 inches) shall be removed to competent native material,
the exposed surface scarified to a depth of 12 inches, brought to within 2% of optimum
moisture content and compacted to a minimum of 90% of the laboratory standard
(ASTM: D-1557-00) prior to placement of any additional compacted fill soils, foundations,
slabs-on-grade and pavement. Grading shall extend a minimum of five horizontal feet
outside the edges of foundations or equidistant to the depth of fill placed, whichever is
greater. Wet soil conditions may be encountered of the grading operations commerce
during or immediately after the rainy season. Stabilization of wet areas may be
necessary which may include the use of gravel, filter fabrics and track mounted
equipment.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 7
It is possible that isolated areas of undiscovered fill not described in this report are
present on site. If found, these areas should be treated as discussed eariier. A diligent
search shall also be conducted during grading operations in an effort to uncover any
underground structures, irrigation or utility lines. If encountered, these structures and
lines shall be either removed or properiy abandoned prior to the proposed construction.
Any imported fill material should be preferably soil similar to the upper soils encountered
at the subject site. All soils shall be approved by this firm prior to importing at the site
and will be subjected to additional laboratory testing to assure concurrence with the
recommendations stated in this report.
Care should be taken to provide or maintain adequate lateral support for all adjacent
improvements and structures at all times during the grading operations and construction
phase. Adequate drainage away from the structures, pavement and slopes should be
provided at all times.
If placement of slabs-on-grade and pavement is not completed immediately upon
completion of grading operations, additional testing and grading of the areas may be
necessary prior to continuation of construction operations. Likewise, if adverse weather
conditions occur which may damage the subgrade soils, additional assessment by the
geotechnical engineer as to the suitability of the supporting soils may be needed.
7.1.2 Fill Blanket Recommendations
Due to the potential for differential settlement of foundations placed on compacted fill
and the underiying bedrock, it is recommended that all foundations be underiain by a
uniform compacted fill blanket at least three feet in thickness. This fill blanket shall
extend a minimum of five horizontal feet outside the edges of foundations or equidistant
to the depth of fill placed, whichever Is greater. Some difficulty in the excavations of the
bedrock may occur and ripping maybe required prior to the use of scrapers for
transporting these soils. A seismic refraction study may be necessary to be performed
by others to determine these conditions.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 8
7.2 Shrinkage and Subsidence
Results of our in-place density tests reveal that the soil shrinkage will be on the order of
5 to 10% due to excavation and recompaction, based upon the assumption that the fill is
compacted to 92% of the maximum dry density per ASTM standards. Subsidence
should be less than 0.1 feet due to earthwork operations. The volume change does not
include any allowance for vegetation or organic stripping, removal of subsurface
improvements or topographic approximations. Although these values are only
approximate, they represent our best estimate of lost yardage which will likely occur
during grading. If more accurate shrinkage and subsidence factors are needed, it is
recommended that field testing using the actual equipment and grading techniques
should be conducted.
7.3 Temporary Excavations
Temporary unsurcharged excavations in the existing site materials less than 4 feet high
may be made at a vertical gradient unless cohesionless soils are encountered.
Temporary unsurcharged excavations from 4 to 6 feet high may be trimmed at a 1 to 1
(horizontal to vertical) gradient In areas where soils with little or no binder are
encountered, where adverse geological conditions are exposed, or where excavations
are adjacent to existing structures, shoring, slot-cutting, or flatter excavations may be
required. The temporary cut slope gradients given do not preclude local raveling and
sloughing. All excavations shall be made in accordance with the requirements of CAL-
OSHA and other public agencies having jurisdiction. Care should be taken to provide or
maintain adequate lateral support for all adjacent improvements and structures at all
times during the grading operations and construction phase.
7.4 Foundation Desian
All foundations may be designed utilizing the following safe bearing capacities for an
embedded depth of 24 inches, into approved fill materials with the corresponding widths:
NorCal Engineering
November 5. 2001 Project Number 9623-01
Page 9
Allowable Safe Bearinq Capacity (psf^
Continuous Isolated
Width (ft) Foundation Foundation
1.5 2000 2500
2.0 2075 2575
4.0 2375 2875
The bearing value may be increased by 500 psf for each additional foot of depth in
excess of the 24 inch minimum depth, up to a maximum of 4,000 psf. A one third
increase may be used when considering short term loading and seismic forces. Any
foundations located along the property lines or where lateral overexcavation is not
possible may utilize a safe bearing capacity of 1,500 psf. A representative of this firm
shall inspect all foundation excavations prior to pouring concrete. All foundations shall
be reinforced with a minimum of one No. 5 bar, top and bottom.
These recommendations may change after the grading operations due to the amount of
grading to be performed. Additional laboratory testing will be performed at that time.
7.5 Settlement Analysis
Resultant pressure curves for the consolidation tests are shown on Plate B.
Computations utilizing these curves and the recommended safe bearing capacities
reveal that the foundations will experience settlements on the order of 3/4 inch and
differential settlements of less than 1/4 inch.
7.6 Lateral Resistance
The following values may be utilized in resisting lateral loads imposed on the structure.
Requirements of the Uniform Building Code should be adhered to when the coefficient of
friction and passive pressures are combined.
Coefficient of Friction - 0.35
Equivalent Passive Fluid Pressure = 200 Ibs./cu.ft.
Maximum Passive Pressure = 2,000 Ibs./cu.ft.
The passive pressure recommendations are valid only for approved compacted fill soils.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 10
7 7 Retaininq Wall Desiqn Parameters
Active earth pressures against retaining wall will be equal to the pressures developed by
the following fluid densities. These values are for granular backfill material placed
behind the walls at various ground slopes above the walls.
Surface Slope of Retained Materials Equivalent Fluid
(Horizontal to Vertican Densitv fib./cu.ft.l
Level 30
5 to 1 35
4 to 1 38
3 to 1 40
2 to 1 45
Any applicable short-term construction surcharges and seismic forces should be added
to the above lateral pressure values. A backfill zone of non-expansive material shall
consist of a wedge beginning a minimum of one horizontal foot from the base of the wall
extending upward at an inclination no less than 1/4 to 1 (horizontal to vertical). All walls
shall be waterproofed as needed and protected from hydrostatic pressure by a reliable
permanent subdrain system.
7.8 Slab Desiqn
All concrete slabs-on-grade shall be at least five inches In thickness and placed on
approved subgrade soils compacted to a minimum of 95% relative compaction in the
upper one foot. Reinforcement requirements and an increase in thickness of the slabs-
on-grade may be necessary based upon proposed loading conditions in the structures.
A vapor barrier overiain by a two inch thick sand layer should be utilized in areas which
would be sensitive to the infiltration of moisture. All concrete slab areas to receive floor
coverings should be moisture tested to meet all manufacturer requirements prior to
placement. All slabs-on-grade shall be reinforced with a minimum of No. 3 bars at 18
inches on-center in both directions positioned in the center of the slab. The upper 18
inches of the subgrade soils shall be molstured to 130% of the optimum moisture
content prior to pouring concrete.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 11
7.9 Pavement Section Desiqn
The table below provides a preliminary pavement design based upon an R-Value of 17
for the proposed pavement areas. Final pavement design may need to be based on R-
Value testing of the subgrade soils near the conclusion of rough grading to assure that
these soils are consistent with those assumed in this preliminary design.
Traffic Asphaltic Base
Type of Traffic Index Concrete (in) Material (in)
Automobile Parking Stalls 4.0 3.0 5.0
Automobile 5.0 3.0 8.0
Circulation Areas
Medium Truck Access Areas 6.0 3.5 10.5
(GVW <42,000 Ibs; 3 axle)
All concrete slabs to be utilized for pavement shall be a minimum of six inches in
thickness and placed on approved subgrade soils. Final pavement section designs for
pavement areas may need to be determined by additional testing of the subgrade near
the conclusion of grading operations. In addition, the above recommendations are
based upon estimated traffic loads. Client should submit anticipated traffic loadings,
when available, so that pavement sections may be reviewed to determine adequacy to
support these loads.
Any approved base material shall consist of a Class II aggregate or equivalent and
should be compacted to a minimum of 95% relative compaction. All pavement materials
shall conform to the requirements set forth by the City of Carisbad. The base material
and asphaltic concrete should be tested prior to delivery to the site and during
placement to determine conformance with the project specifications. A pavement
engineer shall designate the specific asphalt mix design to meet the required project
specifications.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 12
7 10 Utility Trench and Excavation Backfill
Trenches from installation of utility lines and other excavations may be backfilled with
on-site soils or approved imported soils compacted to a minimum of 90% relative
compaction. All utility lines shall be properly bedded with clean sand having a sand
equivalency rating of 30 (SE > 30) or more. This bedding material shall be thoroughly
water jetted around the pipe structure priorto placement of compacted backfill soils.
7.11 Corrosion Desiqn Criteria
Representative samples of the surficial soils, typical of the subgrade soils expected to be
encountered within foundation excavations and underground utilities were tested for
corrosion potential. The minimum resistivity value obtained for the samples tested is
representative of an environment that may be corrosive to metals. The soil pH value
was considered mildly alkaline and shall not have a significant effect on soil corrosivity.
Consideration should be given to corrosion protection systems for buried metal such as
protective coatings, wrappings or the use of PVC where permitted by local building
codes.
According to the latest 'Uniform Building Code (UBC) Table 19-A-3 - Requirements for
Concrete Exposed to Sulfate-Containing Solutions', these contents revealed negligible
levels of sulfate exposure. Therefore, a Type II cement according to latest UBC
specifications may be utilized for building foundations at this time. Additional sulfate
tests shall be performed at the completion of site grading to assure that these soils are
consistent with the recommendations stated in this design. Sulfate test results may be
found on the attached Table IV.
8.0 Closure
The recommendations and conclusions contained in this report are based upon the soil
conditions uncovered in our test excavations. No warranty of the soil condition between
our excavations is Implied. NorCal Engineering should be notified for possible further
recommendations if unexpected to unfavorable conditions are encountered during
construction phase.
NorCal Engineering
November 5, 2001
Page 13
Project Number 9623-01
It is the responsibility of the owner to ensure that all information within this report is
submitted to the Architect and appropriate Engineers for the project. This firm should
have the opportunity to review the final plans to verify that all our recommendations are
incorporated. This report and all conclusions are subject to the review of the controlling
authorities for the project.
A preconstruction conference should be held between the developer, general contractor,
grading contractor, city inspector, architect, and soil engineer to clarify any questions
relating to the grading operations and subsequent construction. Our representative
should be present during the grading operations and construction phase to certify that
such recommendations are complied within the field.
This geotechnical investigation has been conducted in a manner consistent with the
level of care and skill exercised by members of our profession currently practicing under
similar conditions in the Southern California area. No other warranty, expressed or
implied is made.
We appreciate this opportunity to be of service to you. If you have any further questions,
please do not hesitate to contact the undersigned.
Respectfully submitted,
NORCAL ENGINEERING
Keith D. Tucker
Project Engineer
R.G.E. 841
Troy D. Norrell
President
Gail S. Hunt
Project Geologist
C.E.G. 384
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 14
SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILL
Excavation
Any existing low density soils and/or saturated soils shall be removed to competent
natural soil under the inspection of the Soils Engineering Firm. After the exposed
surface has been cleansed of debris and/or vegetation, it shall be scarified until it is
uniform in consistency, brought to the proper moisture content and compacted to a
minimum of 90% relative compaction (in accordance with ASTM: D-1557-00).
In any area where a transition between fill and native soil or between bedrock and soil
are encountered, additional excavation beneath foundations and slabs will be necessary
in order to provide uniform support and avoid differential settlement of the structure.
Material For Fill
The on-site soils or approved import soils may be utilized for the compacted fill provided
they are free of any deleterious materials and shall not contain any rocks, brick,
asphaltic concrete, concrete or other hard materials greater than eight inches in
maximum dimensions. Any import soil must be approved by the Soils Engineering firm a
minimum of 24 hours prior to importation of site.
Placement of Compacted Fill Soils
The approved fill soils shall be placed in layers not excess of six inches in thickness.
Each lift shall be uniform in thickness and thoroughly blended. The fill soils shall be
brought to within 15% of the optimum moisture content, unless otherwise specified by
the Soils Engineering firm. Each lift shall be compacted to a minimum of 90% relative
compaction (in accordance with ASTM: D-1557-00) and approved prior to the placement
of the next layer of soil. Compaction tests shall be obtained at the discretion of the Soils
Engineering firm but to a minimum of one test for every 500 cubic yards placed and/or
for every 2 feet of compacted fill placed.
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 15
The minimum relative compaction shall be obtained in accordance with accepted
methods in the construction industry. The final grade of the structural areas shall be in a
dense and smooth condition prior to placement of slabs-on-grade or pavement areas.
No fill soils shall be placed, spread or compacted during unfavorable weather conditions.
When the grading is Interrupted by heavy rains, compaction operations shall not be
resumed until approved by the Soils Engineering firm.
Grading Observations
The controlling governmental agencies should be notified prior to commencement of any
grading operations. This firm recommends that the grading operations be conducted
under the observation of a Soils Engineering firm as deemed necessary. A 24 hour
notice must be provided to this firm prior to the time of our initial inspection.
Observation shall Include the clearing and gmbbing operations to assure that all
unsuitable materials have been properiy removed; approve the exposed subgrade In
areas to receive fill and in areas where excavation has resulted In the desired finished
grade and designate areas of overexcavation; and perform field compaction tests to
determine relative compaction achieved during fill placement. In addition, all foundation
excavations shall be observed by the Soils Engineering firm to confirm that appropriate
bearing materials are present at the design grades and recommend any modifications to
construct footings.
NorCal Engineering
NorCal Engineering
SOILS AND GliOTUCHNICAL CONSULTANTS
LAMKAI
PROJECT 9623-01 I MTE NOVEKCm 2001
LOCATION OF FIELD EXPLORATIONS
November 5, 2001 Project Number 9623-01
Page 16
List of Appendices
(in order of appearance)
Appendix A - Log of Excavations
Log of Test Excavations TE-1 to TE-7
• Appendix B - Laboratory Tests
• Table I - Maximum Dry Density
» Table II - Expansion Index Tests
• Table III -Sulfate Tests
• Table IV - pH Tests
• Table V - Resistivity Tests
• Table VI - Chloride Tests
• Plate A - Direct Shear
• Plate B - Consolidation
Appendix C - Report by Gall S. Hunt
NorCal Engineering
November 5, 2001 Project Number 9623-01
Page 17
Appendix A
NorCal Engineering
MAJOR OIVISION GRAPHIC
.<«YIURni
LETTER
.<«YMRni
TYPICAL DESCRIPTIONS
COARSE
GRAINED
SOILS
MORE THAN
50% OF
MATERtAL
l.S I ARGER
THAN NO.
200 SIEVE
SIZE
GRAVEL
AND
GRAVELLY
SOILS
MORE THAN
50% OF
COARSE
FRACTION
RETAINED ON
NO. 4 SIEVE
SAND
AND
SANDY
SOILS
MORE THAN
50% OF
COARSE
FRACTION
PASSING ON
NO. 4 SIEVE
CLEAN GRAVELS
(LITTLE OR NG
FINES)
o o
o Oo
GW WELL-GRADED GFIAVELS, GRAVEL.
SAND MIXTURES. LITTLE OR NO FINES
GP POORLY-GRADED GRAVELS,
GRAVEL-SAND MIXTURES, LITTLE
OR NO FINES
GRAVELS
WITH FINES
(APPRECIABLE
AMOUNT OF
FINESt
GM SILTY GRAVELS, GRAVEL-SAND-
SILT MIXTURES
GC CLAYEY GRAVELS, GRAVEL-SAND-
CLAY MIXTURES
CLEAN SAND
(LITTLE OR NO
FINES)
WAV SW WELL-GRADED SANDS, GRAVELLY
SANDS, LITTLE OR NO FINES
SP
POORLY-GRADED SANDS, GRAVEL-
LY SANDS, LITTLE OR NO FINES
SANDS WITH
FINE
(APPRECIABLE
AMOUNT OF
FINES)
SM SILTY SANDS, SAND-SILT
MIXTURES
SC CLAYEY SANDS. SAND-CLAY
MIXTURES
FINE
GRAINED
SOILS
MORE THAN
50% OF
MATERIAL
ISSMALLEB
THAN NO.
200 SIEVE
SIZE
ML
INORGANIC SILTS AND VERY FINE
SANDS, ROCK FLOUR, SILTY OR
CLAYEY FINE SANDS OR CLAYEY
SILTS WITH SLIGHT PLASTICITY
SILTS
AND
CLAYS
LIQUID LIMIT
SILTS
AND
CLAYS
LIQUID LIMIT
50
CL
INORGANIC CLAYS OF LOW TO
MEDIUM PLASTICITY, GRAVELLY
CLAYS, SANDY CLAYS, SILTY
CLAYS, LEAN CLAYS
OL ORGANIC SILTS AND ORGANIC
SILTY CLAYS OF LOW PLASTICITY
MH INORGANIC SILTS, MICACEOUS OR
DIATOMACEOUS FINE SAND OR
SILTY SOILS
CH INORGANIC CLAYS OF HIGH
PLASTICITY, FAT CLAYS
OH ORGANIC CLAYS OF MEDIUM TO
HIGH PLASTICITY, ORGANIC SILTS
HIGHLY ORGANIC SOILS PT
PEAT. HUMUS. SWAMP SOILS WITH
HIGH ORGANIC CONTENTS
NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS
UNIFIED SOIL CLASSIFICATION SYSTEM
NorCal Engineering
KEY:
m
B
3
ZI
Indicates 2.5-inch Inside Diameter. Ring Sample.
Indicates 2-Inch OD Split Spoon Sample (SPT).
Indicates Shelby Tube Sample.
Indicates No Recovery.
Indicates SPT with 140# Hammer 30 in. Drop.
Indicates Bulk Sample.
Indicates Small Bag Sample.
Indicates Non-Standard
Indicates Core Run. COMPONENT PROPORTIONS
COMPONENT DEFINITIONS
COMPONENT SIZE RANGE
Boulders
Cobbles
Gravel
Coarse gravel
Fine gravel
Sand
Coarse sand
Medium sand
Fine sand
Silt and Clav
Larger than 12 in
3 in to 12 in
3 in to No 4 (4.5mm )
3 in to 3/4 in
3/4 in to No 4 (4.5mm )
No. 4 ( 4.5mm ) to No. 200 ( 0.074mm )
No. 4 ( 4.5 mm ) to No. 10 ( 2.0 mm )
No. 10 ( 2.0 mm ) to No. 40 ( 0.42 mm )
No. 40 ( 0.42 mm ) to No. 200 ( 0.074 mm )
Smaller than No. 200 ( 0.074 mm )
DESCRIPTIVE TERMS RANGE OF PROPORTION
Trace 1 - 5%
Few 5-10%
Little 10-20%
Some 20 - 35%
And 35 - 50%
MOISTURE CONTENT
DRY Absence of moisture, dusty. DRY dry to the touch.
DAMP Some perceptible DAMP moisture; below optimum
MOIST No visible water; near optimum MOIST moisture content
WET Visible free water, usually WET
soil is below water table.
RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N -VALUE
COHESIONLESS SOILS COHESIVE SOILS
Density N ( blows/ft) Consistency N (blows/ft) Approximate Density N ( blows/ft)
Undrained Shear
Strength (psf)
Very Loose
Loose
Medium Dense
Dense
Very Dense
Oto 4
4 to 10
10 to 30
30 to 50
over 50
Very Soft
Soft
Medium Stiff
Stiff
Very Stiff
Hard
Oto 2
2 to 4
4 to 8
Sto 15
15 to 30
over 30
<250
250 - 500
500-1000
1000-2000
2000 - 4000
>4000
NorCal Engineering
Log of Test Excavation TE-1
Project: Lanikai/Carlsbad
Date of Drilling: 10/9/01 Groundwater Oepth: None Encountered
Drilling Method: Extension Backhoe
Hammer Weight: Drop: Laboratory
iDepth
1 (feet)
10
15
-20
25
30
35
Geotechnical Description
Surface Elevation: Not Measured
6" DISTURBED TOP SOILS
Silty CLAY
Firm, dry
NATURAL SOILS
Silty CLAY
\ Brow/n, stiff to very stiff, moist
Weathered Shale Bedrock
\Light brown, dry
Boring completed at depth of 4'
NorCal Engineering
Lith-ology
Samples"
« a
Project No.
9623-01
(A
O 3
m o
3.6
21.6
21.7
Q
104.7
105.9
Log of Test Excavation TE-2
Project: Lanikai/Carlsbad
Date of Drilling: 10/9/01 Groundwater Depth: None Encountered
Drilling Method: Extension Backhoe
Hammer Weight: Drop:
Oepth
(feet) Geotechnical Description
Surface Elevation: Not Measured
Lith-ology
tf)
O 3
ca
Tl
3 —
o
JZ
Q is
tf)
- 10
I 15
20
25
30
35
6" DISTURBED TOP SOILS
Silty CLAY
- Firm, div 18.1 104.6
NATURAL SOILS
Silty CLAY
\ Brown, stiff with occasional shale fragments, moist
Weathered Shale Bedrock
,^Light brown, hard, damp
Shale Bedrock with large cobbles
Light brown, very hard
14.1
16.8
101.6
108.1
Boring completed at depth of 9"
NorCal Engineering Project No.
9623-01
Log of Test Excavation TE-3
Project: Lanikai/Carlsbad
Date of Drilling: 10/9/01 Groundwater Depth: None Encountered
Drilling Method: Extension Backhoe
Hammer Weight: Drop:
Laboratory }epth
|(feet)
10
15
20
25
-30
35
Geotechnical Description
Surface Elevation: Not Measured
6" DISTURBED TOP SOILS
Silty CLAY
\Firm, dry
NATURAL SOILS
Silty CLAY
Brown, stiff, damp
Claystone Bedrock
Grey, very hard, damp to moist
Boring completed at depth of 7'
Lith-ology
Samples"
« a
tf)
J c
O 3
"5"
3^
O
JS
14.6
Q gs
108.7
tf)
il.
NorCal Engineering Project No.
9623-01
Log of Test Excavation TE-4
Project: Lanikai/Carlsbad
Date of Drilling: 10/9/01 Groundwater Depth: None Encountered
Drilling Method: Extension Backhoe
Hammer Weight: Drop:
Samples" Laboratory )epth
|<feet)
10
15
20
25
30
35
Geotechnical Description
Surface Elevation: Not Measured
6" DISTURBED TOP SOILS
Clayey SAND with large amounts of gravel, rock and cobbles
Dense, damp
Conglomerate
Extremely dense
Could not penetrate
Boring completed at depth of 1'
Lith-ology »
a.
$ c
O 3
CO ,9
3^
o'^ JE_ Q gs a
tf)
NorCal Engineering Project No.
9623-01
Log of Test Excavation TE-5
Project: Lanikai/Carlsbad
Date of Drilling: 10/9/01 Groundwater Depth: None Encountered
Drilling Method: Extension Backhoe
Hammer Weight: Drop:
• Depth
I (feet)
- 5
10
15
20
•25
30
35
Geotechnical Description
Surface Elevation: Not Measured
6" DISTURBED TOP SOILS
Clayey SAND with gravel, rock and cobbles
Conglomerate
Could not penetrate
Boring completed at depth of 2"
NorCal Engineering
Lith-ology
Samples
«
Q.
Project No.
9623-01
O 3
ffi
3
tf)5->
^
Laboratory
£••2 o" Q gs
Log of Test Excavation TE-6
Project: Lanikai/Carlsbad
Samoles Laboratorv
Oate of Drilling: 10/9/01 Groundwater Depth: None Encountered
Samoles Laboratorv
Drilling Method: Extension Backhoe
Samoles Laboratorv
Hammer Weight: Drop:
Samoles Laboratorv
(feet)
I
I
-10
I
I
I
I
I
I
15
25
30
35
Geotechnical Description
Surface Elevation: Not Measured
6" DISTURBED TOP SOILS
-^ Clayey SAND with large amounts of gravel, rock and cobbles
Conglomerate
Very dense
\Could not penetrate
Boring completed at depth of 2'
Lith-ology a. >«
tf)
O 3
ffi
Mc Q gs Q
«
NorCal Engineering Project No.
9623-01
Log of Test Excavation TE-7
Project: Lanikai/Carlsbad
Date of Drilling: 10/9/01 Groundwater Depth: None Encountered |
Drilling Method: Extension Backhoe
Hammer Weight: Drop:
• Depth
(feet)
! - 0
10
15
20
25
30
35
Geotechnical Description
Surface Elevation: Not Measured
6" DISTURBED TOP SOILS
Silty CLAY with occasional gravel, firm, dry
Silty CLAY
Brown, stiff, damp
Claystone Bedrock
Very stiff
Could not penetrate
Boring completed at depth of 4'
NorCal Engineering
Lith-ology
Samples"
a
Project No.
9623-01
tf)
* c
O 3 ffi O
Laboratory
3^
IS 3?
2.
7.4
Q gs
105.9
tf)
November 5, 2001 Project Number 9623-01
Page 18
Appendix B
NorCal Engineering
Novembers, 2001
Page 20
Project Number 9623-01
Sample
TBI @ 1-3'
TABLE I
MAXIMUM DENSITY TESTS
(ASTM: D-1557-00)
Optimum
Classification Moisture
Silty CLAY 14.0
Maximum Dry
nansitvnbs./cu.ft.)
116.0
Soil Tvoe
TEI @ 1-3'
TABLE II
EXPANSION INDEX TESTS
(U.B.C. STD. 29-2)
Classification
Silty CLAY
Expansion
Index
83
Sample
TEI @ 1-3'
TABLE III
SULFATE TESTS
Sulfate (%)
0.040
ND denotes not detected
% by weight
TABLE IV
DH TESTS
Sample
TEI @ 1-3' 7.2
NorCal Engineering
November 5, 2001
Page 21
Project Number 9623-01
TABLE Y
RESISTIVITY TESTS
(CA 643)
Sample
TEI @ 1-3'
Resistivitv (ohm-cm)
600
TABLE VI
CHLORIDE TESTS
(CA 420.1))
Sample
TEI m 1-3'
Concentration (ppm)
40
NorCal Engineering
2S00
500 1000 1500 2000
NOmU. STRESS (PSF)
2500 3000
srma BORING
NUBER
DEPTH
(FEET) 0
(DEGREES)
C
(PSF)
DRY
DENSITY
(PCF)
NOISTURE
covTEjrr
(X)
X 2 2.5 19 500 104.6 18.1
o 3 4.0 24 625 108.7 14.6
A 7 2.0 14 575 105.9 7.4
•
NOTE: TESTS PERFORMED ON SATURATED SAMPLES UNLESS SHOWN BELOW.
(FM) FIELD MOISTURE
TESTS PERFORMED ON UNDISTURBED SAMPLES UNLESS SHOWN BELOW.
(R) SAMPLES REMOLDED AT 90X OF NKXIMUM DRY DENSITY
NorCal Engineering |
SOILS AND GEOTECHNICAL CONSULTANTS!
PROJECT 9623-01 DATE
DIMECT SHEAR TEST RESULTS
Plate A
SYIML MUK DEPTH
(FEET)
DRY
DEISITY
(PCF)
MOISTURE
canon
(X)
LIQUID
LimT
(X)
PLASTICITY
ISO
(X)
X 2 5 101.6 14.1
O 2 9 108.1 16.8
A 3 4 108.7 14.6
• -
Kt UK ialuii
NorCal Engineering
SOmS AND GEOTECHNICAL CONSULTANTS
PROJECT 9623-01 I DATE
coisiiLiSinai TEST RESULTS
Plate B
November 5, 2001 Project Number 9623-01
Page 19
Appendix C
NorCal Engineering
Gail Hunt Consultant Geologist
P. 0. Box 684
Santa Margarita, CA 93453
Tel: 805 438 4889
October 22, 2001
Subject: Carlsbad Airport. Summit Project
PURPOSE AND DESCRIPTION
The site is being developed as an industrial complex off College Drive and adjacent to
Palomar Airport. The plans call for three buildings; two, two story buildings and one
single story building. The buildings range between 26 thousand and 31 thousand
square feet. Development will require grading of the higher elevations and some filled
areas on the east side of the property. Grading will also require cutting a new access
road to College Blvd.
GEOLOGIC SETTING
The site is located on a Pleistocene age, marine cut terrace surface with a thin veneer
of older colluvium in the lower areas on the east side of the property. The underiying
bedrock was massive white to gray claystone in Test Pits 3 and 7. The bedding was
indistinct but there were some red veins that had a slight dip to the east. The apparent
bedding is shown on Figure 1. Bedding in the five other test pits was a very hard
sandstone and conglomerate with a softer, weathered zone that varied in depth to
several feet or more. The hardest materials were in the center of the site at Test Pits 4
and 5 and along the access road at TP 7.
The claystone bedrock is believed to be part of the Point Loma fomiation of Cretaceous
age. Clay pit excavations are shown in the area. The harder sandstone and
conglomerate are believed to be part of the Santiago formation of Eocene age.
The Tertiary rocks appear to overiay the claystone at elevations of about 315 to 320
feet. The contact between the clay and sandstone/conglomerate was not mapped and
Figure 1 shows the entire site as being underiain by the hard, Tertiary sandstone and
conglomerate sediments. Further mapping may be required.
The elevation of the property varies between about 250 feet in the Northwest corner to
slightly over 330 feet near the center of the property. The pad will vary between
elevation 336 to 322. This grading will remove the upper most ten-ace surface and fill
the lower areas that are covered with a veneer of colluvium.
The sandstone and conglomerate bedrock was difficult to excavate with a backhoe and
could be difficult to excavate even by ripping with heavy equipment.
Published references indicate no significant faults projecting towards the site. The site
is not within a Fault Rupture Hazard Zone as defined by the Califomia Division of Mines
and Geology.
FIELD INVESTIGATIONS
Seven backhoe pits were excavated on the property as shown on the geology map
Figure 1. The pits were logged by me and sampled by you. The pits ranged in depth
to about 9 feet below the ground surface. The location of the pits are shown on Figure
1. Test pits 4 and 5 were terminated at 1 foot depth because the cemented sandstone
and conglomerate was difficult to excavate with the backhoe.
The bedrock, underiying the disturbed surface materials, is mostly massive sandstone,
however claystone was found in Test pits 3 and 7. As discussed above, two geologic
formations are exposed on the site.
GROUNDWATER
There was no evidence of groundwater on the site and future naturally occurring
groundwater is not expected.
EARTHQUAKES AND SEISMICITY
No mapped active faults cross or project towards the site and the potential for active
faulting across the site, within the lifetime ofthe stmcture, is considered remote.
Following are nearby faults with estimated magnitude and peak accelerations which
could be expected to cause strong shaking at the site within the lifetime of the
structure. These accelerations are computed from EQFAULT using attenuation
relationships from Boore et al. (1997).
Fault Distance (miles) Richter Magnitude Peak Acceleration
Rose Canyon 6 6.9 0.32
Newport-Inglewood 9 6.9 0.24
(Ofshore)
Coronado Bank 22 7.4 0.16
Elsinore-Julian 24 7.1 0.13
Other faults at greater distances my cause strong shaking but shouid not exceed the
accelerations values listed above. The seismic risk here is similar to many sites in
Southem Califomia.
The location of the site on competent bedrock is considered to be a favorable condition
for building response to earthquake shaking at the site. Severe damage is possible but
collapse and stmctural failure of the wood frame stmcture is unlikely.
CONCLUSIONS AND RECOMMENDATIONS
The site is considered feasible from a geologic standpoint and the dip of the bedding
does not appear to be an adverse geologic condition. The sandstone is massive and
major slope failures are unlikely. The claystone may be expansive and may have
unfavorable strength characteristics. Separate footing types may be necessary based
upon the results of the soils tests. Ripping or even blasting may be required on the
hard surface of the Santiago formation sandstone and conglomerate. If the two
bedrock types require different treatment, additional exploration may be required.
For preliminary, design assume everything above elevation 315 is in the hard
sandstone/conglomerate.
The footings for the buildings and walls should be in competent bedrock or as directed
by the soils engineer.
Footings in bedrock should be inspected and approved by an engineering geologist.
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