HomeMy WebLinkAboutMS 16-04; VIASAT BRESSI RANCH CAMPUS; UPDATE GEOTECHNICAL INVESTIGATION; 2019-08-29UPDATE GEOTECHNICAL INVESTIGATION
VIASAT BRESSI RANCH - PHASE 5
BUILDINGS 16, 17, AND PARKING STRUCTURE 3
SOUTHWEST CORNER OF
GATEWAY ROAD AND ALICANTE ROAD
CARLSBAD, CALIFORNIA
PREPARED FOR
ViasatT
SAN DIEGO, CALIFORNIA
FEB 2 7 ZoZj
AUGUST 29, 2019 LAND DEVELOP!INT PROJECT NO. G1928-52-02
<,' ow) GEOCON
v
MICHAEL C. Q,
0'( ERTW1NE
No. 2659
i CERTIFIED * ENGINEERING
GEOLOGIST
9vda~3D Michael C. Ertwine
CEG 2659
No. 2714
OF
t
MRL: SFW:MCE:
GEOCON INCORPORATED
Ma
RCE 84154
Aok'
Shawn Foy Weedon
GE 2714
GEOCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL U
Project No. G1928-52-02
August 29, 2019
MATE RI AL S
Viasat
6155 El Camino Real
Carlsbad, California 92009
Attention: Mr. Ryan Hatch
Subi ect: UPDATE GEOTECITINICAL INVESTIGATION
VIASAT BRESSI RANCH - PHASE 5
BUILDINGS 16, 17, AND PARKING STRUCTURE 3
SOUTHWEST CORNER OF GATEWAY ROAD AND ALICANTE ROAD
CARLSBAD, CALIFORNIA
Dear Mr. Hatch:
In accordance with your request and authorization of our Proposal No. LG-19223 dated July 25, 2019,
we herein submit the results of our update geotechnical investigation for the subject project. We
performed our investigation to evaluate the underlying soil and geologic conditions and potential
geologic hazards, and to assist in the design of the proposed building and associated improvements.
The accompanying report presents the results of our study and conclusions and recommendations
pertaining to geotechnical aspects of the proposed project. The site is suitable for the proposed
buildings and improvements provided the recommendations of this report are incorporated into the
design and construction of the planned project.
Should you have questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
(e-mail) Addressee
6960 Flanders Drive 0 San Diego, California 92121-2974 U Telephone 858.558.6900 U Fax 858.558.6159
TABLE OF CONTENTS
PURPOSE AND SCOPE.................................................................................................................
SITE AND PROJECT DESCRIPTION ........................................................................................... 1
GEOLOGIC SETTING .................................................................................................................... 2
SOIL AND GEOLOGIC CONDITIONS ........................................................................................3
4.1 Undocumented Fill (Qudf) ....................................................................................................3
4.2 Previously Placed Compacted Fill (Qpcf).............................................................................3
4.3 Santiago Formation (Ts)........................................................................................................3
G.OUNDWATER ..........................................................................................................................4
GEOLOGIC HAZARDS .................................................................................................................4
6.1 Faulting and Seismicity .........................................................................................................4
6.2 Ground Rupture.....................................................................................................................6
6.3 Liquefaction...........................................................................................................................6
6.4 Storm Surge, Tsunamis, and Seiches.....................................................................................6
6.5 Landslides ........ ..................................................................................................................... 7
CONCLUSIONS AND RECOMMENDATIONS...........................................................................8
7.1 General...................................................................................................................................8
7.2 Excavation and Soil Characteristics ......................................................................................9
7.3 Grading................................................................................................................................10
7.4 Subdrains.............................................................................................................................13
7.5 Excavation Sloçes, Shoring and Tiebacks...........................................................................13
7.6 Soil Nail Wall ......................................................................................................................19
7.7 Seismic Design Criteria.......................................................................................................21
7.8 Settlement Due to Fill Loads...............................................................................................23
7.9 Shallow Foundations (Parking Structure)............................................................................24
7.10 Drilled Pier Recommendations (Buildings 16 and 17)........................................................26
7.11 Concrete Slabs-On-Grade .................................................................................................... 28
7.12 Exterior Concrete Flatwork .................................................................................................30
7.13 Retaining Walls ...................................................................................................................31
7.14 Lateral Loading .................................................................................................................... 34
7.15 Preliminary Pavement Recommendations...........................................................................35
7.16 Site Drainage and Moisture Protection................................................................................38
7.17 Grading and Foundation Plan Review.................................................................................38
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geologic Map (Map Pocket)
Figure 3, Geologic Cross Sections (Map Pocket)
Figure 4, Fill Thickness Map (Map Pocket)
APPENDIX A
PREVIOUS FIELD INVESTIGATION
I
TABLE OF CONTENTS (Concluded)
APPENDIX B
I PREVIOUS LABORATORY TESTING
APPENDIX C
I RECOMMENDED GRADING SPECIFICATIONS
LIST OF REFERENCES
I
I
I
I
I
I
L
I
I
I
I
I
I
I
I
UPDATE GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of our update geotechnical investigation for a new commercial
development located within the Viasat Bressi Ranch campus in the City of San Diego, California (see
Vicinity Map, Figure 1). The purpose of the geotechnical investigation is to evaluate the surface and
subsurface soil conditions and general site geology, and to identify geotechnical constraints that may
affect development of the property including faulting, liquefaction and seismic shaking based on the
2016 CBC seismic design criteria. In addition, we provided recommendations for remedial grading,
shallow and deep foundations, concrete slabs-on-grade, concrete flatwork, pavement and retaining
walls. We reviewed the following plans and geotechnical documents in preparation of this report:
Grading Plans For. Viasat Bressi Ranch, Drawing No. 4974A, Carlsbad, California,
prepared by Pasco Laret Suiter & Associates, approved January 1, 2017.
Minor Site Development Plan for: Viasat Bressi Ranch - SDP Minor Lot 3, Buildings 16-17
and Parking Structure, Carlsbad, California, prepared by Pasco Laret Suiter & Associates,
dated August 19, 2019.
Geotechnical Investigation, Viasat, Bressi Ranch, Carlsbad, California, prepared by Geocon
Incorporated, dated July 5, 2016 (Project No. G1928-52-01).
As-Graded Geotechnical Report, Viasat Bressi Ranch Campus, Gateway Road, Carlsbad,
California, prepared by Christian Wheeler Engineering, dated May 31, 2019 (Project
No. 2170158.26).
The scope of this investigation included reviewing readily available published and unpublished
geologic literature (see List of References), performing engineering analyses, and preparing this
report. Appendices A and B present previous exploratory excavation and laboratory data from our
previous investigation at the site, respectively.
2. SITE AND PROJECT DESCRIPTION
The subject property is located in Bressi Ranch Corporate Center east of El Camino Real, south of
Ga:eway Road, west of Alicante Road and north of Town Garden Road in Carlsbad, California (see
Vicinity Map, Figure 1). We understand the proposed Phase 5 development of the Viasat Campus will
consist of improvements to Parcel 3 located within the northeast portion of the campus. The site is
developed as a sheet-graded pad with storm water basins and a soil stockpile. The soil stockpiles is
located in the southern portion of the site and is up to 35 feet in height. Based on the referenced
grading plans, we expect existing grades range from about 290 feet above mean sea level (MSL) at the
south end of the site adjacent to Town Garden Road to about 325 feet MSL at the northeast property
line adjacent to the intersection of Gateway Road and Alicante Road.
Geocon Project No. G1928-52-02 - I - August 29. 2019
The previous mass grading operations for the Viasat Campus site (prior to the recent development)
were performed between June 2003 and January 2004, resulting in three sheet-graded pads (Parcels 1
through 3). Leighton and Associates performed testing and observation services during the mass
grading operations. Fills of up to approximately 90 feet were placed and cuts of up to approximately
15 feet were made during the overall mass grading operations. The mass grading of the site included
removal of undocumented fill, topsoil, colluvium, alluvium, landslide deposits and weathered
formational material, prior to placing new fill. Canyon subdrain systems were installed in the previous
drainages.
Grading was performed between March 2017 and February 2019 for Parcels 1 and 2 and included
construction of the storm water basin in the southeastern corner of the site. The recent grading
operations were performed for the recently constructed complex for Parcels 1 and 2. Christian Wheeler
performed testing and observation services during the recent grading operations as summarized in the
referenced as-graded report dated May 31, 2019.
The improvements for Phase 5 will consist of the grading for Buildings 16, 17 and Parking Structure P-3.
We understand Building 16 and Parking Structure P-3 will be constructed and Building 17 will be pad-
graded and developed at a later time. We expect Building 16 will be supported on a deep foundation
system likely consisting of drilled piers embedded in the Santiago Formation. We estimate the depths
of the piles will range from approximately 10 to 65 feet below proposed grades. The parking structure
will have 2 subterranean levels and will require the construction of a soil nail wall along the north and
eastern perimeters of the building footprint. We understand the parking structure will be supported on
a conventional shallow foundation system embedded in properly compacted fill.
The locations, site descriptions and proposed development are based on our site reconnaissance,
review of published geologic literature, field investigations, and discussions with project personnel. If
development plans differ from those described herein, Geocon Incorporated should be contacted for
review of the plans and possible revisions to this report.
3. GEOLOGIC SETTING
The site is located within the Peninsular Ranges Geomorphic Province. The region is characterized by
northwest-trending structural blocks and intervening fault zones. The rock types in the Peninsular
Ranges include igneous intrusive rocks associated with the Cretaceous-age Southern California
Batholith, intruded into older volcanic and sedimentary units that were metamorphosed in western and
central San Diego County. In the western part of the county and along the coastal areas, the basement
rocks are overlain by a thick sequence of intermittently deposited Cretaceous to Tertiary-age marine
sedimentary formations, which are the result of transgressive and regressive cycles of the ocean. These
deposits in turn are partially covered by several near shore marine and non-marine, Quaternary-age
terrace deposits that are geologically younger to the west. The site is located in the western portion of
Geocon Project No. G1928-52-02 -2- August 29. 2019
the coastal plain, the site underlain by Eocene-age marine sedimentary deposits of the Santiago
Formation.
4. SOIL AND GEOLOGIC CONDITIONS
Based on our previous investigation at the site and review of the referenced geotechnical reports, we
understand the site geologic conditions consists of one surficial material (consisting of previously
placed compacted fill) overlying one geologic formation (consisting of the Santiago Formation). The
occurrence, distribution, and description of each unit encountered is shown on the Geologic Map,
Figure 2 and on the boring logs in Appendix A. The Geologic Cross-Sections, Figure 3, show the
approximate subsurface relationship between the geologic units. The surficial soil and geologic units
are described herein in order of increasing age.
4.1 Undocumented Fill (Qudf)
A s:ockpile of undocumented fill is located in the area of the proposed P-3 Parking Structure. The
stockpile is associated with the recent development and is about 300 feet wide, 200 feet long and 35
feet high. The undocumented fill is likely comprised of on-site excavations in the existing fill and
formational materials that consist of silty to clayey sand and sandy silt and clay. The undocumented
fill is not appropriate for supporting proposed structures and will require remedial grading or removal.
4.2 Previously Placed Compacted Fill (Qpcf)
Previously placed compacted fill exists at-grade across the majority of the Phase 5 project site. The fill
is associated with the original grading of the site and was observed by Leighton and Associates in
2003 and 2004. The fill consists of silty to clayey sand and sandy silt and clay. The fill was likely
derived from previously existing surficial soil and excavations into the Santiago Formation. The fill
possesses a "very low" to "high" expansion potential (expansion index of 130 or less). We opine that
the previously placed fill is considered suitable for additional fill for structural loads; however,
remedial grading of the upper portion of the fill will be required as discussed herein.
4.3 Santiago Formation (Ts)
The Eocene-aged Santiago Formation is exposed at-grade along the northeastern edge of the site in the
area of proposed Buildings 16 and in the eastern portion of the site in the area of proposed Building 17
and the P-3 Parking Structure. The Santiago Formation was encountered in our previous borings
below the previously placed fill across the remainder of the site. The Santiago Formation consists
primarily of interbedded, yellowish to grayish brown, dense to very dense silty sandstone and hard
claystone and siltstone. Due to the presence of cemented zones (concretions), difficulty in excavation
within the formational materials should be expected. The Santiago Formation is suitable for the
support of proposed structures.
Geocon Project No. G 1928-52-02 - 3 - August 29. 2019
5. GROUNDWATER
We previously encountered seepage perched above the Santiago Formation in our Borings B-2 at
approximately 55 feet below existing grade. We do not expect groundwater to adversely impact the
development of the property. Canyon subdrains were previously constructed throughout the overall
project site, as shown on the Geologic Map, Figure 2. It is not uncommon for groundwater or seepage
conditions to develop where none previously existed. Groundwater elevations are dependent on
seasonal precipitation, irrigation, land use, among other factors, and vary as a result. Proper surface
drainage will be important to future performance of the project.
6. GEOLOGIC HAZARDS
6.1 Faulting and Seismicity
A review of the referenced geologic materials and our knowledge of the general area indicate that the
site is not underlain by active, potentially active, or inactive faults. An active fault is defined by the
California Geological Survey (CGS) as a fault showing evidence for activity within the last
11,000 years. The site is not located within a State of California Earthquake Fault Zone.
According to the computer program EZ-FRISK (Version 7.65), 9 known active faults are located
within a search radius of 50 miles from the property. We used the 2008 USGS fault database that
provides several models and combinations of fault data to evaluate the fault information. Based on this
database, the nearest known active fault is the Newport-Inglewood Fault system, located
approximately 7 miles west of the site, and is the dominant source of potential ground motion.
Earthquakes that might occur on the Newport-Inglewood Fault or other faults within the southern
California and northern Baja California area are potential generators of significant ground motion at
the site. The estimated deterministic maximum earthquake magnitude and peak ground acceleration
for the Newport-Inglewood Fault are 7.5 and 0.32g, respectively. Table 6.1.1 lists the estimated
maximum earthquake magnitude and peak ground acceleration for the most dominant faults in
relationship to the site location. We calculated peak ground acceleration (PGA) using Boore-Atkinson
(2008) NGA USGS2008, Campbell-Bozorgnia (2008) NGA USGS 2008 and Chiou-Youngs (2007)
NGA USGS2008 acceleration-attenuation relationships.
I
I
I
I
I
I
I
I
U
I
I
I
I
I
I
I
[1
Geoon Project No. G 1928-52-02 - 4 - August 29. 2019
TABLE 6.1.1
DETERMINISTIC SPECTRA SITE PARAMETERS
Peak IiGround WAcceleration
Distance iu,r Chiou- Fl
(miles) Magnitude (Mw) Atkinson Bozorgnia Youngs
I Newport-Inglewood 7 7.50 0.28 0.26 0.32
Rose Canyon 7 6.90 0.23 0.24 0.26
Elsinore 21 7.85 0.18 0.13 0.17
Coronado Bank 23 7.40 0.14 0.11 0.12
Palos Verdes Connected 23 7.70 0.16 0.12 0.14
Palos Verdes 39 7.30 0.07 0.06 0.06
Earthquake Valley 39 6.80 0.07 0.05 0.04
San Joaquin Hills 40 7.10 0.08 0.08 0.07
San Jacinto 46 7.88 0.10 007 0.09
We used the computer program EZ-FRISK to perform a probabilistic seismic hazard analysis. The
computer program EZ-FRISK operates under the assumption that the occurrence rate of earthquakes on
each mappable Quaternary fault is proportional to the faults slip rate. The program accounts for fault
rup:ure length as a function of earthquake magnitude, and site acceleration estimates are made using
the earthquake magnitude and distance from the site to the rupture zone. The program also accounts
for uncertainty in each of following: (1) earthquake magnitude, (2) rupture length for a given
magnitude, (3) location of the rupture zone, (4) maximum possible magnitude of a given earthquake,
and (5) acceleration at the site from a given earthquake along each fault. By calculating the expected
accelerations from considered earthquake sources, the program calculates the total average annual
expected number of occurrences of site acceleration greater than a specified value. We utilized
acceleration-attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS 2008,
Campbell-Bozorgnia (2008) NGA USGS 2008 and Chiou-Youngs (2007) NGA USGS2008 in the
analysis. Table 6.1.2 presents the site-specific probabilistic seismic hazard parameters including
acceleration-attenuation relationships and the probability of exceedence.
TABLE 6.1.2
PROBABILISTIC SEISMIC HAZARD PARAMETERS
Geocon ProlectNo. GI928-52-02 -5- - August 29. 2019
While listing peak accelerations is useful for comparison of potential effects of fault activity in a
region, other considerations are important in seismic design, including the frequency and duration of
motion and the soil conditions underlying the site. Seismic design of the structure should be evaluated
in accordance with the California Building Code (CBC) guidelines currently adopted by the City of
Carlsbad.
6.2 Ground Rupture
Ground surface rupture occurs when movement along a fault is sufficient to cause a gap or rupture
where the upper edge of the fault zone intersects the ground surface. The potential for ground rupture
is considered to be very low due to the absence of active faults at the subject site.
6.3 Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are
cohesionless or silt/clay with low plasticity, groundwater is encountered within 50 feet of the surface
and soil densities are less than about 70 percent of the maximum dry densities. If the four previous
criteria are met, a seismic event could result in a rapid pore water pressure increase from the
earthquake-generated ground accelerations. Due to the lack of a permanent, near-surface groundwater
table and the very dense nature of the underlying fill and formational materials, liquefaction potential
for the site is considered very low.
6.4 Storm Surge, Tsunamis, and Seiches
Storm surges are large ocean waves that sweep across coastal areas when storms make landfall. Storm
surges can cause inundation, severe erosion and backwater flooding along the water front. The site is
located approximately 3','2 miles from the Pacific Ocean and is at an elevation of about 290 feet or
greater above Mean Sea Level (MSL). Therefore, the potential of storm surges affecting the site is
considered low.
A tsunami is a series of long period waves generated in the ocean by a sudden displacement of large
volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or offshore
slo?e failures. The site is at a minimum elevation of 290 above feet MSL and is about 31/2 miles from
the Pacific Ocean. Therefore, the potential for the site to be affected by a tsunami is negligible.
A seiche is a run-up of water within a lake or embayment triggered by fault- or landslide-induced
grcund displacement. The site is not located in the vicinity of or downstream from such bodies of
water. Therefore, the risk of seiches affecting the site is negligible.
Geocon Project No. G1928-52-02 -6- August 29. 2019
6.5 Landslides
Based on the examination of aerial photographs and review of published geologic maps compiled by
Kennedy and Tan (2008), it is our opinion that landslides are not present at the property or at a
location that could impact the subject site. According to Leighton and Associates (2011), several
ancient landslides were encountered during the mass grading of the site, and the landslide deposits
were completely removed to competent formational material. Buttresses were also installed to increase
the factor of safety for slope stability to at least 1.5 in accordance with the City of Carlsbad.
Geocon Project No. G1928-52-02 - 7 - August 29., 2019
7. CONCLUSIONS AND RECOMMENDATIONS
7.1 General
7.1 .1 We do not expect that soil or geologic conditions are present at the site that would preclude
the proposed development, provided the preliminary recommendations presented herein are
followed and implemented during design and construction. We will provide supplemental
recommendations if we observe variable or undesirable conditions during construction, or if
the proposed construction will differ from that anticipated herein.
7.1.2 With the exception of possible moderate to strong seismic shaking, we did not observe or
know of significant geologic hazards to exist on the site that would adversely affect the
proposed project.
7.1 .3 Our previous field investigation and subsequent grading reports (by others) indicate the site
is underlain by previously placed compacted fill and dense to very dense Santiago
Formation. The previously placed fill ranges up to 90 feet below existing grades, where
present, and possesses a potential for future settlement on the range up to about 1.6 inches.
The previously placed fill and the Santiago Formation are considered suitable for the
support of additional compacted fill and structures, provided the design team determines
that the proposed structures can tolerate the potential settlements provided. Alternatively, a
deep foundation system can be extended through the fill to the formational materials to
mitigate the potential settlement.
7.1 .4 We did not encounter groundwater during our subsurface exploration and we do not expect
I
it to be a constraint to project development. However, seepage may be encountered during
the grading operations, especially during the rainy seasons. Additionally, seepage could be
I
encountered during drilling operations if deep foundations are planned and constructed. We
encountered seepage at the fill/formational contact in Boring B-2.
7.1.5
Proper drainage should be maintained in order to preserve the engineering properties of the
fill in both the building pads and slope areas. Recommendations for site drainage are
provided herein.
7.1.6 Based on our review of the project plans, we opine the planned development can be
constructed in accordance with our recommendations provided herein. We do not expect the
planned development will destabilize or result in settlement of adjacent properties.
7.1.7 Surface settlement monuments and additional canyon subdrains will not be required on this
project.
Geocori Project No. G1928-52-02 -8 - August 29. 2019
I
1 7.2 Excavation and Soil Characteristics
I
7.2.1 Excavation of the in-situ soil should be possible with moderate to heavy effort using
conventional heavy-duty equipment. Excavation of the formational materials will require
very heavy effort and may generate oversized material using conventional heavy-duty
I equipment during the grading operations. Oversized rock (rocks greater than 12-inches in
dimension) may be generated with the formational materials that can be incorporated into
landscape use or deep compacted fill areas, if available. Oversized materials may be present I in the fill materials as well if buried during the previous grading operations.
I 7.2.2 The soil encountered in our previous field investigation and previous grading operations is
considered to be "expansive" (expansion index [El] of greater than 20) as defined by 2016
I
California Building Code (CBC) Section 1803.5.3. Table 7.2.1 presents soil classifications
based on the expansion index. We expect a majority of the soil encountered possess a "low"
to "high" expansion potential (El of 21 to 130) in accordance with ASTM D 4829.
TABLE 7.2.1
EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX
7.2.3
Previously laboratory test results indicate the on-site materials at the locations tested possess
"SO" to "S2" sulfate exposure to concrete structures as defined by 2016 CBC Section 1904
and ACT 318-14 Chapter 19. The previous laboratory test results are presented in
Appendix B. Table 7.2.2 presents a summary of concrete requirements set forth by 2016
CBC Section 1904 and ACT 318. The presence of water-soluble sulfates is not a visually
I discernible characteristic; therefore, other soil samples from the site could yield different
concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and
other soil nutrients) may affect the concentration. We should perform additional laboratory
I water-soluble sulfate testing during grading operations to evaluate the sulfate exposure at
finish grade elevations of the proposed structure.
'I
Gocon Project No. G1928-52-02 - 9 - August 29, 2019
I
I
I
TABLE 7.2.2
REQUIREMENTS FOR CONCRETE EXPOSED TO
SULFATE-CONTAINING SOLUTIONS
'Maximum water to cement ratio limits do not apply to lightweight concrete
7.2.4 We previously tested samples for potential of hydrogen (pH) and resistivity laboratory tests
to aid in evaluating the corrosion potential to subsurface metal structures. The laboratory
test results are presented in Appendix B..
7.2.5 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore,
further evaluation by a corrosion engineer may be performed if improvements susceptible to
corrosion are planned.
7.3 Grading
7.3.1 Grading should be performed in accordance with the recommendations provided in this
report, the Recommended Grading Specifications contained in Appendix C and the City of
Carlsbad's Grading Ordinance. Geocon Incorporated should observe the grading operations
on a full-time basis and provide testing during the fill placement.
7.3.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the county inspector, developer, grading and underground contractors, civil engineer, and
geotechnical engineer in attendance. Special soil handling and/or the grading plans can be
discussed at that time.
7.3.3 Site preparation should begin with the removal of deleterious material, debris, and
vegetation. The depth of vegetation removal should be such that material exposed in cut
areas or soil to be used as fill is relatively free of organic matter. Material generated during
stripping and/or site demolition should be exported from the site. Asphalt and concrete
should not be mixed with the fill soil unless approved by the Geotechnical Engineer.
Geocon Project No. G1928-52-02 - 10- August 29. 2019
7.3.4 Abandoned foundations and buried utilities (if encountered) should be removed and the
resultant depressions and/or trenches should be backfilled with properly compacted material
as part of the remedial grading.
7.3.5 We expect Buildings 16 and 17 will be supported on a deep foundation system. The upper 2
feet of materials or 2 feet below the proposed grade (whichever results in a deeper removal)
should be removed and replaced with properly compacted fill. The removals should extend
at least 10 feet outside of the proposed foundation zones.
7.3 .6 We expect the planned P-3 Parking structure will be supported on a shallow foundation
system. The upper 5 feet or 2 feet below the proposed foundations (whichever results in a
deeper excavation) should be removed and replaced with properly compacted fill. The
removals should extend at least 10 feet outside of the proposed foundation system, where
possible. iTlils woulil-li reuiFëthe
excavati0
7.3.7 In areas of proposed improvements outside of the building areas, the upper 1 to 2 feet of
existing soil should be processed, moisture conditioned as necessary and recompacted.
Deeper removals may be required in areas where loose or saturated materials are
encountered. The removals should extend at least 2 feet outside of the improvement area,
where possible. Table 7.3.1 provides a summary of the grading recommendations.
TABLE 7.3.1
SUMMARY OF GRADING RECOMMENDATIONS
Area Removal &iIIRequirements
Building Pad - Bldgs. 16 and 17 Removal of Upper 2 Feet of Existing
Materials or 2 Feet Below Pad Grade
Building Pad - Parking P-3 Removal to 5 Feet Below Pad Grade
or 2 Feet Below Footings
Site Development Process Upper 1 to 2 Feet of Existing Materials
Grading Limits 10 Feet Outside of Buildings/2 Feet Outside of
Improvement Areas, Where Possible
Exposed Bottoms of Remedial Grading Scarify Upper 12 Inches
7.3.8 The bottom of the excavations should be sloped 1 percent to the adjacent street or deepest
fill. Prior to fill soil being placed, the existing ground surface should be scarified, moisture
conditioned as necessary, and compacted to a depth of at least 12 inches. Deeper removals
may be required if saturated or loose fill soil is encountered. A representative of Geocon
should be on-site during removals to evaluate the limits of the remedial grading.
Geocon Project No. G1928-52-02 - 11 - August 29, 2019
7.3.9 Some areas of overly wet and saturated soil could be encountered due to the existing
landscape and pavement areas. The saturated soil would require additional effort prior to
placement of compacted fill or additional improvements. Stabilization of the soil would
include scarifying and air-drying, removing and replacement with drier soil, use of
stabilization fabric (e.g. Tensar TX7 or other approved fabric), or chemical treating (i.e.
cement or lime, treatment).
7.3.10 The contractor should be careful during the remedial grading operations to avoid a
"pumping" condition at the base of the removals. Where recompaction of the excavated
bottom will result in a "pumping" condition, the bottom of the excavation should be tracked
with low ground pressure earthmoving equipment prior to placing fill. [fedëWiöimprove
flTe i15ilit5fihe excavatiiibttoms,
compactEFfil1J
7.3.11 The site should then be brought to final subgrade elevations with fill compacted in layers. In
general, soil native to the site is suitable for use from a geotechnical engineering standpoint
as fill if relatively free from vegetation, debris and other deleterious material. Layers of fill
should be about 6 to 8 inches in loose thickness and no thicker than will allow for adequate
bonding and compaction. Fill, including backfill and scarified ground surfaces, should be
compacted to a dry density of at least 90 percent of the laboratory maximum dry density
near to slightly above optimum moisture content in accordance with ASTM Test Procedure
D 1557. Fill materials placed below optimum moisture content may require additional
moisture conditioning prior to placing additional fill. The upper 12 inches of subgrade soil
underlying pavement should be compacted to a dry density of at least 95 percent of the
laboratory maximum dry density near to slightly above optimum moisture content shortly
before paving operations.
7.3.12 Import fill (if necessary) should consist of the characteristics presented in Table 7.3.2.
Geocon Incorporated should be notified of the import soil source and should perform
laboratory testing of import soil prior to its arrival at the site to determine its suitability as
fill material.
TABLE 7.3.2
SUMMARY OF IMPORT FILL RECOMMENDATIONS
Gocon Project No. G 1928-52-02 - 12 - August 29.. 2019
I
1 7.4 Subdrains
7.4.1 With the exception of retaining wall drains, we do not expect the installation of other
1 subdrains.
I 7.4.2 A canyon subdrain exists in the northern portion of the property and drains in a northeast-to-
southwest direction. The drain is located in the southeastern portion of Building 16 and
I
northwestern portion of Building 17. The proposed drilled piers should be located in areas
outside of the drain so the continued operation of the drain occurs.
I 7.5 Excavation Slopes, Shoring and Tiebacks
7.5.1 The recommendations included herein are provided for stable excavations. It is the
I responsibility of the contractor to provide a safe excavation during the construction of the
proposed project.
7.5.2 Temporary excavations should be made in conformance with OSHA requirements and as
directed by the assigned competent person in the field (contractor). In general, special
I shoring requirements may not be necessary if temporary excavations will be less than 4 feet
in height. Temporary excavations greater than 4 feet in height, however, should be sloped
I back at an appropriate inclination. These excavations should not be allowed to become
saturated or to dry out. Surcharge loads should not be permitted to a distance equal to the
height of the excavation from the top of the excavation. The top of the excavation should be
I a minimum of 15 feet from the edge of existing improvements. Excavations steeper than
those recommended or closer than 15 feet from an existing surface improvement should be
I shored in accordance with applicable OSHA codes and regulations. ' 7.5.3 The design of temporary shoring is governed by soil and groundwater conditions, and by the
depth and width of the excavated area. Continuous support of the excavation face can be
provided by a system of soldier piles and wood lagging or sheet piles. Excavations
I exceeding 15 feet may require soil nails, tieback anchors or internal bracing to provide
additional wall restraint.
7.5.4 The condition of existing buildings, streets, sidewalks, and other structures/improvements
around the perimeter of the planned excavation should be documented prior to the start of
shoring and excavation work. Special attention should be given to documenting existing
cracks or other indications of differential settlement within these adjacent structures,
I pavements and other improvements. Underground utilities sensitive to settlement should be
videotaped prior to construction to check the integrity of pipes. In addition, monitoring
points should be established indicating location and elevation around the excavation and
Geocon Project No. G1928-52-02 - 13- August 29. 2019
upon existing buildings. These points should be monitored on a weekly basis during
excavation work and on a monthly basis thereafter. Inclinometers should be installed and
monitored behind any shoring sections that will be advanced deeper than 30 feet below the
existing ground surface.
7.5.5 In general, ground conditions are moderately suited for soldier pile and tieback anchor wall
construction techniques. However, gravel, cobble, and oversized material may be
encountered in the existing materials that could be difficult to drill. Additionally, if
cohesionless sands are encountered, some raveling may result along the unsupported
portions of excavations. Cemented zones may be encountered within the formational units
and could cause difficult excavations.
7.5.6 Temporary shoring with a level backfill should be designed using a lateral pressure
envelope acting on the back of the shoring as presented in Table 7.5.1 assuming a level
backfill. The distributions are shown on the Active Pressures for Temporary Shoring.
Triangular distribution should be used for cantilevered shoring and, the trapezoidal and
rectangular distribution should be used for multi-braced systems such as tieback anchors and
rakers. The project shoring engineer should determine the applicable soil distribution for the
design of the temporary shoring system. Additional lateral earth pressure due to the
surcharging effects from construction equipment, sloping backfill, planned stockpiles,
adjacent structures and/or traffic loads should be considered, where appropriate, during
design of the shoring system.
TABLE 7.5.1
SUMMARY OF TEMPORARY SHORING WALL RECOMMENDATIONS
11Parameter L(
Triangular Distribution, A 26H psf
Rectangular Distribution, B 17H psf
Trapezoidal Distribution, C 21H psf
Passive Pressure, P 350D + 500 psf
Effective Zone Angle, E 29 degrees
Maximum Design Lateral Movement 1 Inch
Maximum Design Vertical Movement '/2 Inch
Maximum Design Retained Height, H 30 Feet
H equals the height of the retaining portion of the wall in feet
D equals the embedment depth of the retaining wall in feet
Geocon Project No. G 1928-52-02 - 14 - August 29, 2019
SIDIDIER P
WALL $
EXCAVATION
BOUO
rvW '.1k'e6 LQ I flIV I TVII
Active Pressures on Temporary Shoring
7.5.7 The passive resistance can be assumed to act over a width of three pile diameters. Typically,
soldier piles are embedded a minimum of 0.5 times the maximum height of the excavation
(this depth is to include footing excavations) if tieback anchors are not employed. The
project structural engineer should determine the actual embedment depth.
7.5.8 Lateral movement of shoring is associated with vertical ground settlement outside of the
excavation. Therefore, it is essential that the soldier pile and tieback system allow very
limited amounts of lateral displacement. Earth pressures acting on a lagging wall can cause
movement of the shoring toward the excavation and result in ground subsidence outside of
the excavation. Consequently, horizontal movements of the shoring wall should be
accurately monitored and recorded during excavation and anchor construction.
Geccon Project No. @1928-52-02 -15- August 29. 2019
I
I
I
I
I
I
I
I
I
I
I
1
I
I
I
I
I
I
I
I
I
EXCAVATION
BOTTOM
r
D(ft)
GROUTED
F SOLDIER PILE
Passive Pressures on Temporary Shoring
7.5.9 Survey points should be established at the top of the pile on at least 20 percent of the soldier
piles. An additional point located at an intermediate point between the top of the pile and the
base of the excavation should be monitored on at least 20 percent of the piles if tieback
anchors will be used. These points should be monitored on a weekly basis during excavation
work and on a monthly basis thereafter until the permanent support system is constructed.
7.5.10 The project civil engineer should provide the approximate location, depth, and pipe type of
the underground utilities to the shoring engineer to help select the shoring type and shoring
design. The shoring system should be designed to limit horizontal soldier pile movement to
a maximum of 1 inch. The amount of horizontal deflection can be assumed to be essentially
zero along the Active Zone and Effective Zone boundary, as shown in the Active Zone
Detail herein. The magnitude of movement for intermediate depths and distances from the
shoring wall can be linearly interpolated.
I
I Geocon Project No. G1928-52-02 -16- August 29, 2019
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
ESTIMATED 1 MAXIMUM
HORIZONTAL MOVEMENT\\ EXISTING GROUND SURFACE
ESTIMATED 17 MAXIMUM
VERTICAL MOVEMENT /
IVE / NE /
/ T
Active Zone Detail
7.5.1 1 We should observe the drilled shafts for the soldier piles prior to the placement of steel
reinforcement to check that the exposed soil conditions are similar to those expected and
that footing excavations have been extended to the appropriate bearing strata and design
depths. If unexpected soil conditions are encountered, foundation modifications may be
required.
7.5.12 Experience has shown that the use of pressure grouting during formation of the bonded
portion of the anchors will increase the soil-grout bond stress. A pressure grouting tube
should be installed during the construction of the tieback. Post grouting should be performed
if adequate capacity cannot be obtained by other construction methods.
7.;5. 13 Anchor capacity is a function of construction method, depth of anchor, batter, diameter of
the bonded section and the length of the bonded section. Anchor capacity should be
evaluated using the strength parameters shown in Table 7.5.2.
Geocoii Project No. G1928-52-02 - 17- August 29. 2019
TABLE 7.5.2
SOIL STRENGTH PARAMETERS FOR TEMPORARY SHORING
7.5.14 Grout should only be placed in the tieback anchor's bonded section prior to testing. Tieback
anchors should be proof-tested to at least 130 percent of the anchor's design working load.
Following a successful proof test, the tieback anchors should be locked off at 80 percent of
the allowable working load. Tieback anchor test failure criteria should be established in
project plans and specifications. The tieback anchor test failure criteria should be based
upon a maximum allowable displacement at 130 percent of the anchor's working load
(anchor creep) and a maximum residual displacement within the anchor following stressing.
Tieback anchor stressing should only be conducted after sufficient hydration has occurred
within the grout. Tieback anchors that fail to meet project specified test criteria should be
replaced or additional anchors should be constructed.
7.5.15 Lagging should keep pace with excavation. The excavation should not be advanced deeper
than three feet below the bottom of lagging at any time. These unlagged gaps of up to three
feet should only be allowed to stand for short periods of time in order to decrease the
probability of soil instability and should never be unsupported overnight. Backfilling should
be conducted when necessary between the back of lagging and excavation sidewalls to
reduce sloughing in this zone and all voids should be filled by the end of each day. Further,
the excavation should not be advanced further than four feet below a row of tiebacks prior to
those tiebacks being proof tested and locked off unless otherwise specific by the shoring
engineer.
7.5.16 If tieback anchors are employed, an accurate survey of existing utilities and other
underground structures adjacent to the shoring wall should be conducted. The survey should
include both locations and depths of existing utilities. Locations of anchors should be
adjusted as necessary during the design and construction process to accommodate the
existing and proposed utilities.
7.5.17 The shoring system should incorporate a drainage system for the proposed retaining wall as
shown herein.
Geocon Project No. G1928-52-02 - 18- August 29. 2019
FINISH
GRADE
SLAB.• ... I
SOLDIER PILE AND WOOD
(IF PLANNED) LAGGING SHORING WALL SLAB
BUItDING
RETAINING
WALL MIRADRAIN 6000 OR
EQUIVALENT DRAINAGE
PANELS
WATERPROOFING
PER PRO' ECT__.J_1 r I H (FT.)
ARCHITECT
I PERFORATED COLLECTOR DRAIN (OR OTHER) IA SCHEDULE 40 PVC PIPE UNIFORMLY SOLID SCHEDULE 40 IA SLOPED LEADING TO POSITIVE PVC PIPE (IF REQUIRED) 1.1 GRAVITY OUTLET OR SUMP PUMP
SLAB
CONNECTED TO
CONTROLLED
DRAINAGE DEVICE
PROPERLY WATERPROOFED AT
WALL TO PREVENT WATER FROM
MIGRATING BELOW SLAB
Shoring Drainage System Detail
7.6 Soil Nail Wall
7.6.1 As an alternative to temporary shoring followed by construction of a permanent basement
wall, a soil nail wall can be used. Soil nail walls consist of installing closely spaced steel
bars (nails) into a slope or excavation in a top-down construction sequence. Following
installation of a horizontal row of nails, drains, waterproofing and wall reinforcing steel are
placed and shotcrete applied to create a final wall. The wall should be designed by an
engineer familiar with the design of soil nail walls.
7..6.2 Temporary soil nail walls should not be considered a permanent design to support the
seismic lateral loads and soil pressures on a building wall. Therefore, the proposed building
should be designed to support the expected lateral loads.
7.6.3 In general, ground conditions are moderately suited to soil nail wall construction techniques.
However, localized gravel, cobble and oversized material could be encountered in the
existing materials that could be difficult to drill. Additionally, relatively clean sands may be
Geocon Project No. G1928-52-02 - 19- August 29, 2019
encountered within the existing soil that may result in some raveling of the unsupported
excavation. Casing or specialized drilling techniques should be planned where raveling
exists.
7.6.4 Testing of the soil nails should be performed in accordance with the guidelines of the
Federal Highway Administration or similar guidelines. At least two verification tests should
be performed to confirm design assumptions for each soil/rock type encountered.
Verification tests nails should be sacrificial and should not be used to support the proposed
wall. The bond length should be adjusted to allow for pullout testing of the verification nails
to evaluate the ultimate bond stress. A minimum of 5 percent of the production nails should
also be proof tested and a minimum of 4 sacrificial nails should be tested at the discretion of
Geocon Incorporated. Consideration should be given to testing sacrificial nails with an
adjusted bond length rather than testing production nails. Geocon Incorporated should
observe the nail installation and perform the nail testing.
7.6.5 The soil strength parameters listed in Table 7.6 can be used in design of the soil nails. The
bond stress is dependent on drilling method, diameter, and construction method. Therefore,
the designer should evaluate the bond stress based on the existing soil conditions and the
construction method.
TABLE 7.6
SOIL STRENGTH PARAMETERS FOR SOIL NAIL WALLS
*Assuming gravity fed, open hole drilling techniques.
7.6.6 A wall drain system should be incorporated into the design of the soil nail wall as shown
herein. Corrosion protection should be provided for the nails if the wall will be a permanent
structure.
Geocon Project No. G1928-52-02 -20- - August 29. 2019
_.- MIRADRAIN 6000 OR EQUIVALENT 12 L
6
MN.
0 MIN.
WHERE
I PLATE
EXCAVATION AND NUT
FACE
FIRST LAYER OF
SHOT CRETE FACING
SOIL NAIL
AND GROUT
=I FINISH FACE OF
SOIL NAIL WALL
MIRADRAIN &EO
OR EQUIVALENT
DRAINAGE PANELS
DRAINAGE PANELS PER SOIL NAIL WALL ENGINEER EXCAVATION
FACE
PERFORATED COLLECTOR DRAIN
SCHEDULE 40 PVC PIPE IOR OTHER)
UNIFORMLY SLOPED LEADING TO SOIL NAIL
POSITIVE GRAVITY OUTLET OR
CONTROLLED DRAINAGE DEVICE
GROUT
FINISH
SURFACE \
Soil Nail Wall Detail
7.7 Seismic Design Criteria
7.7.1 We used the computer program Seismic Design Maps, provided by the Structural Engineers
Association of California and based on guidelines provided by the California Building
Code. Table 7.7.1 summarizes site-specific design criteria obtained from the 2016 California
Building Code (CBC; Based on the 2015 International Building Code [IBC] and ASCE 7-
10), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral
response uses a period of 0.2 second. The buildings and improvements should be designed
using a Site Class D. We evaluated the Site Class based on the discussion in
Section 1613.3.2 of the 2016 CBC and Table 20.3-1 of ASCE 7-10. The values presented in
Table 7.7.1 are for the risk-targeted maximum considered earthquake (MCER).
Geocon Project No. G1928-52-02 -21 - August 29. 2019
I
I
1
I
I
TABLE 7.7.1
2016 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2016 CBC Reference
Site Class I D I
Section 1613.3.2
MCER Ground Motion Spectral Response 1.050g Figure 1613.3.1(1) Acceleration — Class B (short), Ss
MCER Ground Motion Spectral Response O.407g Figure 1613.3.1(2) Acceleration - Class B (1 sec),
Site Coefficient, FA 1.080g Table 1613.3.3(1)
Site Coefficient, Fv 1.593g Table 1613.3.3(2)
Site Class Modified MCER Spectral
Response Acceleration (short), SMS 1.134g Section 1613.3.3 (Eqn. 16-37)
Site Class Modified MCER Spectral
Response Acceleration (1 sec), SMI 0.648g Section 16 13.3.3 (Eqn. 16-38)
5% Damped Design Spectral
Response Acceleration (short), SDS 0.756g Section 1613.3.4 (Eqn. 16-39)
5% Damped Design Spectral
Response Acceleration (1 sec), 0.432g Section 1613.3.4 (Eqn. 16-40)
7.7.2 Table 7.7.2 presents additional seismic design parameters for projects located in Seismic
Design Categories of D through F in accordance with ASCE 7-10 for the mapped maximum
considered geometric mean (MCEG).
TABLE 7.7.2
2016 CBC SITE ACCELERATION DESIGN PARAMETERS
11Parameter 'fur
Site Class I D --
Mapped MCEG
Peak Ground Acceleration, PGA 0.403g Figure 22-7
Site Coefficient, FPGA 1.097 Table 11.8-1
Site Class Modified MCEG
Peak Ground Acceleration, PGAM 0.442g Section 11.8.3 (Eqn. 11.8-1)
7.7.3 Conformance to the criteria in Tables 7.7.1 and 7.7.2 for seismic design does not constitute
any kind of guarantee or assurance that significant structural damage or ground failure will
not occur if a large earthquake occurs. The primary goal of seismic design is to protect life,
not to avoid all damage, since such design may be economically prohibitive.
Geocon Project No. G1928-52-02 -22 - August 29. 2019
I
I
I
I
7.7.4 The project structural engineer and architect should evaluate the appropriate Risk Category
and Seismic Design Category for the planned structures. The values presented herein
assume a Rick Category of I, II or III and resulting in a Seismic Design Category D.
7.8 Settlement Due to Fill Loads
7.8.1 Fill soil, even if properly compacted, will experience settlement over the lifetime of the
improvements that it supports. The ultimate settlement potential of the fill is a function of
the soil classification, placement relative compaction, and subsequent increases in the soil
moisture content.
7.8.2 The Phase 5 development area is underlain by a maximum fill thickness on the order of
90 feet (75 feet within the building areas). The settlement of compacted fill is expected to
continue over a relatively extended time period resulting from both gravity loading and
hydrocompression upon wetting from rainfall and/or landscape irrigation. The previously
placed fill has existed for approximately 15 years; therefore, a majority of the expected
settlement has likely occurred.
7.8.3 Due to the variable fill thickness, a potential for differential settlement across the proposed
buildings exist and special foundation design consideration as discussed herein will be
necessary. Based on measured settlement of similar fill depths on other sites and the time
period since the fill was placed, we estimate that maximum settlement of the compacted fill
will be approximately 0.15 percent for the existing compacted fills. The Fill Thickness and
Settlement Map, Figure 4 provides the approximate thickness of fill and estimated
maximum fill settlement in the area of the proposed buildings and improvements.
7.8.4 Table 7.8 presents the estimated total and differential fill thickness and settlements of the
building pads for the proposed pad grades provided on the referenced plans. These
settlement magnitudes should be considered in design of the foundation system and adjacent
flatwork that connects to the proposed buildings.
TABLE 7.8
EXPECTED DIFFERENTIAL SETTLEMENT OF FILL SOIL
I
Geocon Project No. G1928-52-02 -23 - August 29, 2019
1 7.8.5 Deep foundations such as driven piles or drilled piers are the most effective means of
reducing the ultimate settlement potential of the proposed structures to a negligible amount.
Alternatively, highly reinforced shallow foundation systems and slabs-on-grade may be
used for support of the buildings; however, the shallow foundation systems would not
eliminate the potential for cosmetic distress related to differential settlement of the
underlying fill. Some cosmetic distress should be expected over the life of the structure as a
result of long-term differential settlement. The owner, tenants, and future owners should be
made aware that cosmetic distress, including separation of caulking at wall joints, small
non-structural wall panel cracks, and separation of concrete flatwork is likely to occur.
Recommendations for deep foundations can be provided to evaluate the comparative risks
and costs upon request.
1 7.9 Shallow Foundations (Parking Structure)
7.9.1 We understand the proposed P-3 Parking Structure can be supported on a shallow
foundation system founded in compacted fill materials. Foundations for the structure should
consist of continuous strip footings and/or isolated spread footings. Table 7.9 provides a
summary of the foundation design recommendations. The fill settlements, discussed herein,
should be incorporated into the design of the parking structure as well.
TABLE 7.9
SUMMARY OF FOUNDATION RECOMMENDATIONS
Parameter
Bearing Material
'1tii•
I Compacted Fill
Minimum Continuous Foundation Width 12 inches
Minimum Isolated Foundation Width 24 inches
Minimum Foundation Depth 24 Inches Below Lowest Adjacent Grade
Minimum Steel Reinforcement -
Continuous Foundations 4 No. 5 Bars, 2 at the Top and 2 at the Bottom
Bearing Capacity - Fill 2,500 psf
Bearing Capacity Increase 5 00 psf per Foot of Depth
500 psf per Foot of Width
Maximum Bearing Capacity - Fill 4,000 psf
Estimated Total Settlement 1 Inch
Estimated Differential Settlement V2 Inch in 40 Feet
Footing Size Used for Settlement 10-Foot Square
Design Expansion Index 130 or less
Geocon Project No. G)928-52-02 -24- August 29. 2019
I
I
I
I
1
7.9.2 The foundations should be embedded in accordance with the recommendations herein and
the Wall/Column Footing Dimension Detail. The embedment depths should be measured
from the lowest adjacent pad grade for both interior and exterior footings. Footings should
be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally
from the face of the slope.
CONCRETE SLAB
\ :jt..'
;/1 JI... PAD GRADE
A4 ND . . . RETARDER IN
ACCORDANCE WITH Ad
Ow cc 4 QW 00
LL
FOOTING' FOOTING'
WIDTH WIDTH
Wall/Column Footing Dimension Detail
7.9.3 The bearing capacity values presented herein are for dead plus live loads and may be
increased by one-third when considering transient loads due to wind or seismic forces.
7.9.4 Where buildings or other improvements are planned near the top of a slope steeper than 3:1
(horizontal: vertical), special foundations and/or design considerations are recommended due
to the tendency for lateral soil movement to occur.
For fill slopes less than 20 feet high, building footings should be deepened such that
the bottom outside edge of the footing is at least 7 feet horizontally from the face of
the slope.
When located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the
foundations should be extended to a depth where the minimum horizontal distance
is equal to H13 (where H equals the vertical distance from the top of the fill slope to
the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The
horizontal distance is measured from the outer, deepest edge of the footing to the
face of the slope. An acceptable alternative to deepening the footings would be the
use of a post-tensioned slab and foundation system or increased footing and slab
reinforcement. Specific design parameters or recommendations for either of these
alternatives can be provided once the building location and fill slope geometry have
been determined.
Although other improvements, which are relatively rigid or brittle, such as concrete
flatwork or masonry walls, may experience some distress if located near the top of a
slope, it is generally not economical to mitigate this potential. It may be possible,
Geccon Project No. G1928-52-02 -25- August 29. 2019
however, to incorporate design measures that would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
7.9.5 We should observe the foundation excavations prior to the placement of reinforcing steel
and concrete to check that the exposed soil conditions are similar to those expected and that
they have been extended to the appropriate bearing strata. Foundation modifications may be
required if unexpected soil conditions are encountered.
7.9.6 Geocon Incorporated should be consulted to provide additional design parameters as
required by the structural engineer.
7.10 Drilled Pier Recommendations (Buildings 16 and 17)
7.10.1 We understand that drilled piers may be used for foundation support. The foundation
recommendations herein assume that the piers will extend through the fill into the Santiago
Formation. The piers should be embedded at least 5 feet within the formational materials.
7.10.2 Piers can be designed to develop support by end bearing within the formational materials
and skin friction within the formational materials and portions of the fill soil. An allowable
skin friction resistance of 300 psf and 500 psf can be used for that portion of the drilled pier
embedded in fill soil and formational materials, respectively. The end bearing capacity can
be determined by the End Bearing Capacity Chart. These allowable values possess a factor
of safety of at least 2 and 3 for skin friction and end bearing, respectively.
Geocon Project No. G1928-52-02 -26- August 29. 2019
20
... 30
C)
0
50 0
C) CO 60
Allowable End Bearing Capacity, kips
0 100 200 300 400 500 600 700 800 900 1000
0 .
10
24-Inch Dia.
A 30-Inch Dia.
36-Inch Dia.
X 48-Inch Dia.
Mm. Pile Length
0 70
80
90
100
End Bearing Capacity Chart
7.10.3 The diameter of the piers should be a minimum of 24-inches. The piles should be embedded
into the formational materials at least 5 feet and have a minimum length of 10 feet. The
design length of the drilled piers should be determined by the designer based on the
elevation of the pile cap or grade beam and the elevation of the top of the formational
materials obtained from the Geologic Map and Geologic Cross-Sections presented herein. It
is difficult to evaluate the exact length of the proposed drilled piers due to the variable
thickness of the existing fill; therefore, some variation should be expected during drilling
operations.
7. i 0.4 If pier spacing is at least three times the maximum dimension of the pier, no reduction in
axial capacity for group effects is considered necessary. If piles are spaced between 2 and
3 pile diameters (center to center), the single pile axial capacity should be reduced by
25 percent. Geocon Incorporated should be contacted to provide single-pile capacity if piers
are spaced closer than 2 diameters.
Geocon Project No. G1928-52-02 -27- August 29, 2019
7.10.5 The allowable downward capacity may be increased by one-third when considering
transient wind or seismic loads.
7.10.6 The formational materials may contain gravel and cobble and may possess very dense
zones; therefore, the drilling contractor should expect difficult drilling conditions during
excavations for the piers. Because a significant portion of the piers capacity will be
developed by end bearing, the bottom of the borehole should be cleaned of loose cuttings
prior to the placement of steel and concrete. Experience indicates that backspinning the
auger does not remove loose material and a flat cleanout plate is necessary. We expect
localized seepage may be encountered during the drilling operations and casing may be
required to maintain the integrity of the pier excavation, particularly if seepage or sidewall
instability is encountered. Concrete should be placed within the excavation as soon as
possible after the auger/cleanout plate is withdrawn to reduce the potential for
discontinuities or caving.
7.1 C'.7 Pile settlement of production piers is expected to be on the order of V2 inch if the piers are
loaded to their allowable capacities. Geocon should provide updated settlement estimates
once the foundation plans are available. Settlements should be essentially complete shortly
after completion of the building superstructure.
7.10.8 We can provide a lateral pile capacity analysis using the LPILE or GROUP computer
programs once the pile type, size, and approximate length has been provided.
7.11 Concrete Slabs-On-Grade
7.11 .1 Concrete slabs-on-grade for the structures should be constructed in accordance with
Table 7.11.
TABLE 7.11
MINIMUM CONCRETE SLAB-ON-GRADE RECOMMENDATIONS
7.11.2 Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture-
sensitive materials should be underlain by a vapor retarder. The vapor retarder design should
Gocon Prolect No. G1928-52-02 -28- August 29, 2019
be consistent with the guidelines presented in the American Concrete Institute's (ACT) Guide
for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACT 302.2R-06). In
addition, the membrane should be installed in accordance with manufacturer's
recommendations and ASTM requirements and installed in a manner that prevents puncture.
The vapor retarder used should be specified by the project architect or developer based on the
type of floor covering that will be installed and if the structure will possess a humidity
controlled environment.
7.11.3 The bedding sand thickness should be determined by the project foundation engineer,
architect, and/or developer. It is common to have 3 to 4 inches of sand for 5-inch and 4-inch
thick slabs, respectively, in the southern California region. However, we should be
contacted to provide recommendations if the bedding sand is thicker than 6 inches. The
foundation design engineer should provide appropriate concrete mix design criteria and
curing measures to assure proper curing of the slab by reducing the potential for rapid
moisture loss and subsequent cracking and/or slab curl. We suggest that the foundation
design engineer present the concrete mix design and proper curing methods on the
foundation plans. It is critical that the foundation contractor understands and follows the
recommendations presented on the foundation plans.
7.11.4 Concrete slabs should be provided with adequate crack-control joints, construction joints
and/or expansion joints to reduce unsightly shrinkage cracking. The design of joints should
consider criteria of the American Concrete Institute (ACT) when establishing crack-control
spacing. Crack-control joints should be spaced at intervals no greater than 12 feet.
Additional steel reinforcing, concrete admixtures and/or closer crack control joint spacing
should be considered where concrete-exposed finished floors are planned.
7.', 1.5 Special subgrade presaturation is not deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soil should be moisturized to maintain a moist
condition as would be expected in any such concrete placement.
7.11.6 The concrete slab-on-grade recommendations are based on soil support characteristics only.
The project structural engineer should evaluate the structural requirements of the concrete
slabs for supporting expected loads.
7.11.7 The recommendations of this report are intended to reduce the potential for cracking of slabs
due to expansive soil (if present), differential settlement of existing soil or soil with varying
thicknesses. However, even with the incorporation of the recommendations presented
herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still
exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete
Geocon Project No. G 1928-52-02 -29 - August 29. 2019
I
I
I shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may
be reduced and/or controlled by limiting the slump of the concrete, proper concrete
placement and curing, and by the placement of crack control joints at periodic intervals, in
- particular, where re-entrant slab corners occur.
7.12 Exterior Concrete Flatwork
I 7.12.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the recommendations presented in Table 7.12. The recommended steel
reinforcement would help reduce the potential for cracking.
TABLE 7.12
MINIMUM CONCRETE FLATWORK RECOMMENDATIONS
In excess of 8 feet square.
7.12.2 Even with the incorporation of the recommendations of this report, the exterior concrete
flatwork has a potential to experience some uplift due to expansive soil beneath grade. The
steel reinforcement should overlap continuously in flatwork to reduce the potential for
vertical offsets within flatwork. Additionally, flatwork should be structurally connected to
the curbs, where possible, to reduce the potential for offsets between the curbs and the
flatwork.
7.12.3 Concrete flatwork should be provided with crack control joints to reduce and/or control
shrinkage cracking. Crack control spacing should be determined by the project structural
engineer based upon the slab thickness and intended usage. Criteria of the American
Concrete Institute (ACI) should be taken into consideration when establishing crack control
spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted
in accordance with criteria presented in the grading section prior to concrete placement.
Subgrade soil should be properly compacted and the moisture content of subgrade soil
should be verified prior to placing concrete. Base materials will not be required below
concrete improvements.
Gocon Project No. G1928-52-02 -30- August 29, 2019
I
I
I
I
I
I
1
I
7.12.4
7.12,5
7.13.2
Where exterior flatwork abuts the structure at entrant or exit points, the exterior slab should
be dowelled into the structure's foundation stemwall. This recommendation is intended to
reduce the potential for differential elevations that could result from differential settlement
or minor heave of the flatwork. Dowelling details should be designed by the project
structural engineer.
The recommendations presented herein are intended to reduce the potential for cracking of
exterior slabs as a result of differential movement. However, even with the incorporation of
the recommendations presented herein, slabs-on-grade will still crack. The occurrence of
concrete shrinkage cracks is independent of the soil supporting characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, the use
of crack control joints and proper concrete placement and curing. Crack control joints
should be spaced at intervals no greater than 12 feet. Literature provided by the Portland
Concrete Association (PCA) and American Concrete Institute (AC!) present
recommendations for proper concrete mix, construction, and curing practices, and should be
incorporated into project construction.
Retaining Walls
Retaining walls should be designed using the values presented in Table 7.13.1. Soil with an
expansion index (El) of greater than 90 should not be used as backfill material behind
retaining walls.
TABLE 7.13.1
RETAINING WALL DESIGN RECOMMENDATIONS
Parameter
Active Soil Pressure, A (Fluid Density, Level Backfill)
Value
I
M1Il2MZ
35 pcf 40 pcf
Active Soil Pressure, A (Fluid Density, 2:1 Sloping Backfill) 45 psf 55 pcf
Seismic Pressure, S 14H psf
At-Rest/Restrained Walls Additional Uniform Pressure (0 to 8 Feet High) 7H psf
At-Rest/Restrained Walls Additional Uniform Pressure (8+ Feet High) 13H psf
Expected Expansion Index for the Subject Property EI90
H equals the height of the retaining portion of the wall
The project retaining walls should be designed as shown in the Retaining Wall Loading
Diagram.
7.13
7.13.1
Gocon Project No. G1928-52-02 -31 - -- August 29. 2019
SEISMIC
(IF REQUIRED)
1r: DPrQPKIT ACTIVE
RESSURE
13H psf
AT-REST/
RESTRAINED
(IF REQUIRED)
H s 8
H>8
L
Retaining Wall Loading Diagram
7.13.3 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals
the height of the retaining portion of the wall) at the top of the wall. Where walls are
restrained from movement at the top (at-rest condition), an additional uniform pressure
should be added to the active soil pressure. For retaining walls subject to vehicular loads
within a horizontal distance equal to two-thirds the wall height, a surcharge equivalent to
2 feet of fill soil should be added.
7.13.4 The structural engineer should determine the Seismic Design Category for the project in
accordance with Section 1613.3.5 of the 2016 CBC or Section 11.6 of ASCE 7-10. For
structures assigned to Seismic Design Category of D, E, or F, retaining walls that support
more than 6 feet of backfill should be designed with seismic lateral pressure in accordance
with Section 1803.5.12 of the 2016 CBC. The seismic load is dependent on the retained
height where 1-1 is the height of the wall, in feet, and the calculated loads result in pounds per
square foot (psf) exerted at the base of the wall and zero at the top of the wall.
7.13.5 Retaining walls should be designed to ensure stability against overturning sliding, and
excessive foundation pressure. Where a keyway is extended below the wall base with the
intent to engage passive pressure and enhance sliding stability, it is not necessary to
consider active pressure on the keyway.
Geocon Project No. 01928-52-02 -32 - August 29, 2019
I
7.13.6 Drainage openings through the base of the wall (weep holes) should not be used where the
seepage could be a nuisance or otherwise adversely affect the property adjacent to the base
of the wall. The recommendations herein assume a properly compacted granular (El of 90 or
less) free-draining backfill material with no hydrostatic forces or imposed surcharge load.
The retaining wall should be properly drained as shown in the Typical Retaining Wall
Drainage Detail. If conditions different than those described are expected, or if specific
drainage details are desired, Geocon Incorporated should be contacted for additional
recommendations.
CONCRETE GROUND SURFACE CONCRETE BROWDITCH GROIJND SURFACE BROWOFICH
pqopos€o
RETAIN IN G
WAL L J
RETAINING WALL PROPERLY
COMPACTED
PER OSHA I WATER PROOFING
PER ARCHITECT
WATERPROOFING PEF:ARCHITECT +—._
H _ OR
-
-
DRAINAGE PANEL
- )MIRAORAIN BOOS
OR EQUIVALENT)
23 H '.... MIRAFI 140N FILTER FABRIC 20 H - 3I4 CRUSHED ROCK I2 . •.. (OR EQUIVALENT) (1 CU.FTJFT.) OR WRAP
* OPEN GRADED -
ORAINAGE PANEL
AROUND PIPE
PROPOSED I, MAX. AGGREGATE FILTER FABRIC GRADE PROPOSED - ENVELOPE
ING 4 OW. PERFORATED SCHEDULE
GRADE
EOUIVALE
40 C PIPE EXTENDED TO FOOTING 4 01k SCHEDULE 40
APPROVED OUTLET _______________ PERFORATED C PIPE
' OR TOTAL DRAIN
EXTENDED TO
APPROVED OUTLET
12 Typical Retaining Wall Drainage Detail
7.13.7 The retaining walls may be designed using either the active and restrained (at-rest) loading
condition or the active and seismic loading condition as suggested by the structural
I engineer. Typically, it appears the design of the restrained condition for retaining wall
loading may be adequate for the seismic design of the retaining walls. However, the active
I earth pressure combined with the seismic design load should be reviewed and also
considered in the design of the retaining walls.
1 7.13.8 In general, wall foundations having should be designed in accordance with Table 7.13.2.
The proximity of the foundation to the top of a slope steeper than 3:1 could impact the
I allowable soil bearing pressure. Therefore, retaining wall foundations should be deepened
such that the bottom outside edge of the footing is at least 7 feet horizontally from the face
of the slope.
I
I
I
Geocon Project No. G1928-52-02 -33 - August 29. 2019
TABLE 7.13.2
SUMMARY OF RETAINING WALL FOUNDATION RECOMMENDATIONS
i1Parameter
Minimum Retaining Wall Foundation Width
'1tI[
12 inches
Minimum Retaining Wall Foundation Depth 12 Inches
Minimum Steel Reinforcement Per Structural Engineer
Bearing Capacity 2,000 psf
Estimated Total Settlement * 1 Inch
Estimated Differential Settlement 1/2 Inch in 40 Feet
*Total settlement due to foundation loads - settlement of the existing fill should additionally be
accounted for.
7.13.9 The recommendations presented herein are generally applicable to the design of rigid
concrete or masonry retaining walls. In the event that other types of walls (such as
mechanically stabilized earth [MSE] walls, soil nail walls, or soldier pile walls) are planned,
Geocon Incorporated should be consulted for additional recommendations.
1 7.13.10 Unrestrained walls will move laterally when backfilled and loading is applied. The amount
of lateral deflection is dependent on the wall height, the type of soil used for backfill, and
I loads acting on the wall. The retaining walls and improvements above the retaining walls
should be designed to incorporate an appropriate amount of lateral deflection as determined
by the structural engineer.
7.13.11 Soil contemplated for use as retaining wall backfill, including import materials, should be
I identified in the field prior to backfill. At that time, Geocon Incorporated should obtain
samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures
I may be necessary if the backfill soil does not meet the required expansion index or shear
strength. City or regional standard wall designs, if used, are based on a specific active lateral
earth pressure and/or soil friction angle. In this regard, on-site soil to be used as backfill may I or may not meet the values for standard wall designs. Geocon Incorporated should be
consulted to assess the suitability of the on-site soil for use as wall backfill if standard wall
designs will be used.
7.14 Lateral Loading
7.14.1 Table 7.14 should be used to help design the proposed structures and improvements to resist
I lateral loads for the design of footings or shear keys. The allowable passive pressure
assumes a horizontal surface extending at least 5 feet, or three times the surface generating
1
Geocon Project No. G1928-52-02 -34- August 29, 2019
I
I
the passive pressure, whichever is greater. The upper 12 inches of material in areas not
protected by floor slabs or pavement should not be included in design for passive resistance.
TABLE 7.14
SUMMARY OF LATERAL LOAD DESIGN RECOMMENDATIONS
*Per manufacturer's recommendations.
7.14.2 The passive and frictional resistant loads can be combined for design purposes. The lateral
passive pressures may be increased by one-third when considering transient loads due to
wind or seismic forces.
7.15 Preliminary Pavement Recommendations -
7.15.1 ëãlcuiãd the flexible pavemenftions in general conformance with the caltrans,
hfF1ëib7ëP9vernen7
med iiiiii
tëkiffic areas, andieavy fckffic areas,tilThe pm iilineer and
wner shVdiëJiIhe pavement di tiötö?1EtëThiine
avemenf11iiEkness. Thfiuii pavementëti iisfdiihe
encount fin-5175- bWdIVãthnTW have assume diiii
presents tlFe
liiñflibie pavementtiii
irABtE7:115:11
RE[LMINARYFEEXEBtE:RAVEMENLSECT1ON
Geocon Project No. G 1928-52-02 -35 - August 29. 2019
7.1 5.2 rnatëiilthe upper 12 iii! scarifi
'5iTüre condi1iiid as necessary, and recompacted -9 per nt'f
hëibory maximum d5d7nity near iii1itliãbove optimum moiture confiifã,
ëtiiifbSTMD"f537) Similarly, the base material should be compacted to a dry
density of at least 95 percent of the laboratory maximum dry density near to slightly above
optimum moisture content. Asphalt concrete should be compacted to a density of at least 95
percent of the laboratory Hveem density in accordance with ASTM D 2726.
Ii
I
I
7.15.3 A rigid Portland cement concrete (PCC) pavement section should be placed in roadway
aprons and cross gutters. We calculated the rigid pavement section in general conformance
with the procedure recommended by the American Concrete Institute report AC! 330R-08
Guide for Design and Construction of Concrete Parking Lots using the parameters presented
in Table 7.15.2.
I TABLE 7.15.2
RIGID PAVEMENT DESIGN PARAMETERS
I
iii
I
I
Ii]
I
I
7.15.4 ______pavemenf fii1i5tiFdhave a miiiiñTiiii
I liikness as presentëThl7T53
I LTABEE'7-15:3
IR1G1DTLVEHICUrAREAVEMENrRECOMMENDATIONS
F
I
I 55ThPCC7eHi5-1ar over su T—soil—tFa—t—is cpacted
_ percentfTh1ãbtory maximum dity near
fimum moiture contëiiCTliis pavement secti ibd on a miiiimum concret 1 pressrëtrengtWöT approxi l3OOOi(pounds per square iiih
1
Ge•Dcon Project No. G 1928-52-02 -36 - August 29, 2019
7.15.6 T-tME or iii aFiiibliUidbe constited thëUtidëöf concrete s1ãb
9-u- je—ct-e-d-to—wh—e-el-IFa-dF-Tlfe—tliiZ or
iiiiimum tliiëkness ofTiiihes,liihever resultii liikiIiige,Per
ecommendëliãliffiikness ofThil1 (e.g., 6-inch and 7.5-inch-
thick slabs would have an 8- and 9.5-inch-thick edge, respectively). Reinforcing steel will
not be necessary within the concrete for geotechnical purposes with the possible exception
of dowels at construction joints as discussed herein.
7.15.7 To control the location and spread of concrete shrinkage cracks, crack-control joints
(weakened plane joints) should be included in the design of the concrete pavement slab.
Crack-control joints should not exceed 30 times the slab thickness with a maximum spacing
of 12 feet for 5.5-inch-thick and 15 feet for the 6.0-inch and thicker slabs and should be
sealed with an appropriate sealant to prevent the migration of water through the control joint
to the subgrade materials. The depth of the crack-control joints should be determined by the
referenced AC! report. The depth of the crack-control joints should be at least ¼ of the slab
thickness when using a conventional saw, or at least 1 inch when using early-entry saws on
slabs 9 inches or less in thickness, as determined by the referenced AC! report discussed in
the pavement section herein. Cuts at least '/4 inch wide are required for sealed joints, and a
inch wide cut is commonly recommended. A narrow joint width of '/to- to 'I8-inch wide is
common for unsealed joints.
7.15.8 To provide load transfer between adjacent pavement slab sections, a butt-type construction
joint should be constructed. The butt-type joint should be thickened by at least 20 percent at
the edge and taper back at least 4 feet from the face of the slab. As an alternative to the butt-
type construction joint, dowelling can be used between construction joints for pavements of
7 inches or thicker. As discussed in the referenced ACT guide, dowels should consist of
smooth, 1-inch-diameter reinforcing steel 14 inches long embedded a minimum of 6 inches
into the slab on either side of the construction joint. Dowels should be located at the
midpoint of the slab, spaced at 12 inches on center and lubricated to allow joint movement
while still transferring loads. In addition, tie bars should be installed at the as recommended
in Section 3.8.3 of the referenced ACI guide. The structural engineer should provide other
alternative recommendations for load transfer.
7.15.9 Concrete curb/gutter should be placed on soil subgrade compacted to a dry density of at
least 90 percent of the laboratory maximum dry density near to slightly above optimum
moisture content. Cross-gutters that receives vehicular should be placed on subgrade soil
compacted to a dry density of at least 95 percent of the laboratory maximum dry density
near to slightly above optimum moisture content. Base materials should not be placed below
the curb/gutter, or cross-gutters so water is not able to migrate from the adjacent parkways
Geocon Project No. C 1928-52-02 -37- August 29. 2019
to the pavement sections. Where flatwork is located directly adjacent to the curb/gutter, the
concrete flatwork should be structurally connected to the curbs to help reduce the potential
for offsets between the curbs and the flatwork.
7.16 Site Drainage and Moisture Protection
7.16.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2016 CBC 1804.4 or other applicable
standards. In addition, surface drainage should be directed away from the top of slopes into
swales or other controlled drainage devices. Roof and pavement drainage should be directed
into conduits that carry runoff away from the proposed structure.
7.16.2 In—the case of basementlibiling _areas, a water-proofiff
tëiiTh&iTiVbe use dW1hë7ãlVãiiWjThñts,
hiidThëiãl over the waterproofiuiThe projectãiliitEt of ciVil iineer sli5i11d,
on thIiifdiill ãterproofing andiinä e.
7.16.3 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water is allowed to infiltrate the soil for prolonged periods of time.
7. 16.4 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement's subgrade and base course. Area drains
to collect excess irrigation water and transmit it to drainage structures or impervious above-
grade planter boxes can be used. In addition, where landscaping is planned adjacent to the
pavement, construction of a cutoff wall along the edge of the pavement that extends at least
6 inches below the bottom of the base material should be considered.
7.17 Grading and Foundation Plan Review
7.17.1 Geocon Incorporated should review the grading and building foundation plans for the
project prior to final design submittal to evaluate if additional analyses and/or
recommendations are required.
Cexon Project No. G1928-52-02 -38- August 29.. 2019
LIMITATIONS AND UNIFORMITY OF CONDITIONS
The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of prcject geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during construction,
or if the proposed construction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or corrosive materials was not part of the
scope of services provided by Geocon Incorporated.
This report is issued with the understanding that it is the responsibility of the owner or his
representative to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors carry out
such recommendations in the field.
The findings of this report are valid as of the present date. However, changes in the
conditions of a property can occur with the passage of time, whether they be due to natural
processes or the works of man on this or adjacent properties. In addition, changes in
applicable or appropriate standards may occur, whether they result from legislation or the
broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly
or partially by changes outside our control. Therefore, this report is subject to review and
should not be relied upon after a period of three years.
Geocon Project No. G1928-52-02 August 29. 2019
1
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
TA
A -
THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH
SUBJECT TO A LICENSING AGREEMENT THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY IT IS
NOT INTENDED FOR CLIENTS USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT CLIENT
SHALL INDEMNIFY. DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT
OF SUCH USE OR RELIANCE BY CLIENT NO SCALE
VICINITY MAP
GEOCON JAN
INCO RPO RATED
GEOTECHNICAL. ENVIRONMENTAL • MATERIALS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974
PHONE 858 558-6900 - FAX 858 558-6159
ML/CW DSK/GTYPD
Plotted 08/30/2019 9:10AM I By ALVIN LADRILLONO I File Location Y \PROJECTS\G1928-52-02 Visat-Phase 5\DETAILS\G1928-52-02 ViciriityMa dwg
VIASAT- PHASE 5
CARLSBAD, CALIFORNIA
DATE 08-29-2019 1 PROJECT NO. G1928 - 52 -02 1 FIG. -
APPENDIX
APPENDIX A
PREVIOUS FIELD INVESTIGATION
We performed the drilling operations on the Phase 3 lot on April 4 through 5, 2016 which included
Borings B-i, B-2, B-5 and B-6 prior to the recent construction operations. The borings extended to
maximum depth of approximately 67 feet. The locations of the previous exploratory borings are
shown on the Geologic Map, Figure 2. The boring logs are presented in this Appendix. We located
the borings in the field using a measuring tape and existing reference points; therefore, actual boring
locations may deviate slightly.
We obtained samples during our previous subsurface exploration in the borings using either a
California sampler or a Standard Penetration Test (SPT) sampler. Both samplers are composed of
steel and are driven to obtain ring samples. The California sampler has an inside diameter of 2.5
inches and an outside diameter of 3 inches. Up to 18 rings are placed inside the sampler that is 2.4
inches in diameter and 1 inch in height. The SPT sampler has an inside diameter of 1.5 inches and an
outside diameter of 2 inches. We obtained ring samples at appropriate intervals, placed them in
moisture-tight containers, and transported them to the laboratory for testing. The type of sample is
noted on the exploratory boring logs.
The California sampler and SPT sampler were driven 12 and 18 inches, respectively. The sampler is
connected to A rods and driven into the bottom of the excavation using a 140-pound hammer with a 30-
inch drop. Blow counts are recorded for every 6 inches the sampler is driven. The penetration
resistances shown on the boring logs are shown in terms of blows per foot. The values indicated on the
boring logs are the sum of the last 12 inches of the sampler. If the sampler was not driven for 12 inches,
an approximate value is calculated in term of blows per foot or the final 6-inch interval is reported.
These values are not to be taken as N-values as adjustments have not been applied. We estimated
elevations shown on the boring logs either from a topographic map or by using a benchmark. Each
excavation was backfihled as noted on the boring logs.
We visually examined, classified, and logged the soil encountered in the borings in general
accordance with American Society for Testing and Materials (ASTM) practice for Description and
Identification of Soils (Visual-Manual Procedure D 2488). The logs depict the soil and geologic
conditions observed and the depth at which samples were obtained.
Geocon Project No. G1928-52-02 - August 29. 2019
PROJECT NO. G1928-52-01
DEPTH
IN
FEET
SAMPLE
NO.
>-
0<
-J
w
0
0
SOIL
CLASS
BORINGBI
ELEV. (MSL.)31 7' DATE COMPLETED 04-04-2016
EQUIPMENT MARL M-5 BY: L. RODRIGUEZ
0
Z
<<Cl)
Cl)
0
0 0
MATERIAL DESCRIPTION
- 0
- BI-1 :7 - SC/CL PREVIOUSLY PLACED FILL (Qpct)
-
- Medium dense, moist, olive brown, Clayey, fine to coarse SAND to Sandy -
- 2 - .j./.CLAY -
:;••. .
-4-
-6-
B1-2 //: -Few to little chunks of silty sand 22
-
-8- /....
,-. ..
-
- 10
- BI-3 -Becomes wet, trace shell fragments - 18 107.4 18.7
-
12
i..>...: (p.p. 4.5+tsf) -
-
14- //
- :'/"<
-
16-
B14 /4. -Few to little layers/chunks of yellowish to grayish fine sand and gray silt 21
./• ..
-
:/..
- 20 - - -
BI-5 (pp. 4.5+tsO - 23 98.8 30.7
-22- /. -
>...... ....
-24- ./.. -
Bi 6 7' 26
- 28 - :• ...:..:. -
__
30
- - BI-7 :. (pp. 4.5+tsf) 27 99.2 24.7
-32-
- 34 - :..•: -
Figure A-I,
Log of Boring B I, Page I of 2
SAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL LI ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
In DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH .00ATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GE000N
PROJECT NO. Gi1928-52-01
>.LU o . BORING B I zw —
DEPTH SOIL Z Cl)
SAMPLE
NO. 0 CLASS
x
IN ELEV. (MSL.)317 DATE COMPLETED 04-04-2016
ci)
I- 0
I.. z
FEET (USCS) 0 IX W Cl) 0 z 20
EQUIPMENT MARL M-5 BY: L. RODRIGUEZ 0
MATERIAL DESCRIPTION
BI-8 .7... 39
36-
- 38 -
BI-9 :1: ML Hard, moist, grayish to yellowish brown, Sandy SILT; little to some chunks 46 104.6 15.3
- -: clay and sand
42 - (i'-r- 4.5+tsf)
44
- BI-10 SM SANTIAGO FORMATION (Ts) 84/9"
46 Very dense, damp, gray to yellowish brown, Silty, fine SANDSTONE; weakly
- :::1::: cemented; laminated with magnesium
48
50
- BI-11 .- - 85/9"
BORING TERMINATED AT 50.75 FEET
No groundwater encountered
Backfilled with 10.0 ft' bentonite grout slurry
Figure A-I,
Log of Boring B I, Page 2of2
SAMPLE SYMBOLS El SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST I ... DRIVE SAMPLE (UNDISTURBED)
99 DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. G928-52-01
>
IX BORING B 2
DEPTH -
SOIL _03i-
iz SAMPLE
NO.
9 0 CLASS ELEV. (MSL.)308 DATE COMPLETED 04.05-2016 0 FEET
EQUIPMENT MARL M-5 BY: L. RODRIGUEZ CL
- 0 MATERIAL DESCRIPTION
132-1 :TT: - SM PREVIOUSLY PLACED FILL (Qpcl)
. Medium dense, damp, yellowish to grayish brown, Silty, fine to medium
- 2 -EJ.E SAND; trace gravel; trace organics
4.
-
B2-2 -Becomes wet, trace to little layers/chunks dark olive brown, sandy clay 25 122.9 12.6
6
- 8
10 14
B2-3 CL Stiff, moist, dark olive brown, Sandy CLAY; trace gravel 29
-12-
- 14
B2-4 -::1. 1-:: : SM/ML Medium dense, damp, gray, Silty, fine SAND to Sandy SILT; trace shell 33 119.1 6.4
- 16 fragments
(pp. 4.0 tsf)
18
20 B2-5 .::1iTh.: SM Medium dense, moist, yellowish to grayish brown, Silty, fine SAND; trace 30 121.0 11.0
shell fragments
22
24
132-6 ::.I.:.::1:: 41 26
28
30 132-7 .:i -Trace gravel 44 109.6 16.5
(pp. 4.5+tsf)
32
_
34
Figure A-2,
Log of Boring B 2, Page 1 of 2
SAMPLE SYMBOLS LI ... SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SLBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. G1928-52-01
BORING B 2
DEPTH
>-
0 SOIL P Z X SAMPLE
NO.
j
z CLASS ELEV. (MSL.)308 DATE COMPLETED 04.05-2016
<<(I)Z LL I—
FEET M (USCS)
EQUIPMENT MARL M-5 BY: L RODRIGUEZ LU °-
_____ MATERIAL DESCRIPTION
-
- B2-8 :' - Sc Medium dense, moist, yellowish to grayish brown, clayey, fine SAND 40
36
- -
-38-
- 40 - - - - -
B2-9 SM Medium dense, moist, yellowish to grayish brown, Silty, fine SAND 39 110.3 12.1
(pp. 4.5+tsf)
42
44
B2-10 :'J11 -Becomes damp 49 46 -
48 H
50
- B2-11 . -Becomes very dense, wet; fine content decreases; little to some shell 85/11 114.2 17.4 -
- :•'.i.J: fragments; trace clay
- 52 - .J...
- _______
(pp. 4.5+tsf)
54 -
-
- B2-12 Slight seepage SM / 72
- 56 - SANTIAGO FORMATION (Ts) -
Very dense, wet, grayish to yellowish brown, Silty, fine SANDSTONE; -
- weakly cemented 58
- ::E:
-
-
60 B2-13 : :::
BORING TERMINATED AT 61.5 FEET
Slight seepage encountered at 55 feet
Backfilled with 12.1 ft' bentonite grout slurry
Figure A-2,
Log of Boring B 2, Page 2 of 2
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
99 DISTURBED OR BAG SAMPLE ..: CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED, IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. G1928-52-01
DEPTH
IN
FEET
SAMPLE
NO.
>-
j
<
0
SOIL
Cl-ASS
BORING B 5
ELEV. (MSL.)318 DATE COMPLETED 04-04-2016
EQUIPMENT MARL M-5 BY: L. RODRIGUEZ
O
p Z
(I)
w. -
(1) I-.
..
MATERIAL DESCRIPTION
- 135-1 jTi - SM PREVIOUSLY PLACED FILL (Qpct)
-
- ...t-.1.. Medium dense, damp to moist, light yellowish to grayish brown, Silty, fine to
- 2 - medium SAND; trace chunks of gray silt
:.'..
-
- B5-2 :...:ç 33
8 H
- 10
- B5-3 ::t..1.. 27 116.1 17.5
- 12
-
:14: ::.:T.::
B54 CL/SC Stiff, moist, olive brown, Sandy CLAY to Clayey, fine to medium SAND 21 116.4 13.5
16 7. (pp. 4.5+tsf)
-18-
20 B5-5 ::] :1:: SM Medium dense, moist, light yellowish to grayish brown, Silty, fine to medium 34
SAND -
22 -
24
B5-6 .-1Ji1. -Becomes coarser grained; trace to few chunks of olive brown sandy clay 27 121.3 10.4
- 26 - ..:.i.: (pp. 4.5+tsf)
- 28
-
30 B5-7 .i. :It. -Trace gravel-sized rock fragments - 41
32 H
34
Figure A-5,
Log of Boring B 5, Page 1 of 2
SAMPLE SYMBOLS El SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
12 DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE Y ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OZ SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GE000N
PROJECT NO. G1928-52-01
BORING B 5 > QoSOIL i-. DEPTH
SAMPLE I-Z )
FEET
CLASS ELEV. (MSL.)318 DATE COMPLETED 04-04-2016
o Ix 20
EQUIPMENT MARL M-5 BY: L. RODRIGUEZ Lu -
MATERIAL DESCRIPTICN
-
- B5-8 f:T:i - (pp. 4.5+tsf) 41 106.9 19.3
36
38
40 B5-9 :7:>>. CL Stiff; moist, yellowish to grayish brown, Sandy CLAY; trace rock fragments; 24
-
- trace to few chunks of silt; trace wood debris -
- 42 - :. .. -
- 44
-
- B5-10 (pp. 4.5+tsO 23 105.1 20.5
- 46
- 48 - . -
50 B5-11 :..i>.2: -Trace wood debris
-
30
- 52
- 54 - .:- •. -
- 56
- 58
-60-
B5-12 Sc SANTIAGO FORMATION (Is) 92/9"
-
- Very dense, damp, yellowish brown, Clayey, fine to medium SANDSTONE;
- 62 - weakly cemented; trace magnesium
-64- -
-
- 135-13 SM/TvIL
66 - - moderately cemented; micaceous
BORING TERMINATED AT 66.5 FEET
Very dens; damp, Silty, fine SANDSTONE to Sandy SILTSTONE--87/11"
No groundwater encountered
Backfihled with 13.1 ft' bentonite gr•Jut slurry
Figure A-5,
Log of Boring B 5, Page 2 of 2
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL E ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE Y ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. G1928-52-01
BORING B 6
DEPTH 0 < SOIL
>-LU O.
Z
IN SAMPLE .. 0 CLASS << CI) I- >
ZLL. W0 LU z
FEET NO. (USCS) ELEV. (MSL.)310 DATE COMPLETED 04-05-2016 0
0 Z Lu IX 20 IX EQUIPMENT MARL M-5 BY: L. RODRIGUEZ CL 0
MATERIAL DESCRIPTION
- 0
- B6-1 - SM PREVIOUSLY PLACED FILL (Qpct)
-
- : Medium dense, damp, light yellowish brown to olive brown, Silty, fine to -
- 2 - medium SAND; trace clay -
-
- 136-2 34
-
6
- 8
10 136-3 />. CL Stiff, moist, olive dark brown, Sandy CLAY 22 108.6 18.7
(pp. 4.5+tsf) -
- 12 - ::: SM SANTIAGO FORMATION (Ts) -
- - Very dense, damp, yellowish to grayish brown, Silty, fine SANDSTONE; -
: weakly cemented
- 14
B64 81/11' - 16 BORING TERMINATED AT 16 FEET
No groundwater encountered
Figure A-6,
Log of Boring B 6, Page 1 of I
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
APPENDIX
APPENDIX B
PREVIOUS LABORATORY TESTING
We previously performed laboratory tests in accordance with generally accepted test methods of the
American Society for Testing and Materials (ASTM) or other suggested procedures. Selected soil samples
were tested for in-place dry density and moisture content, maximum density and optimum moisture
content, direct shear strength, expansion index, water soluble sulfate, R-Value, consolidation, and
gradation characteristics. The results of our current laboratory tests are presented in Tables B-I through
13-VII and on Figures B-I through B-25. The in-place dry density and moisture content of the samples
tested are presented on the boring logs in Appendix A.
TABLE B-I
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM 0 1557
TABLE B-Il
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
ASTM D 3080
'Ultimate at end of test at 0.2 inch deflection
TABLE B-Ill
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829
Geocon Project No. G 1928-52-02 - B-I - August 29. 2019
TABLE B-IV
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS
CALIFORNIA TEST NO. 417
TABLE B-V
SUMMARY OF LABORATORY PH AND RESISTIVITY RESULTS
CALIFORNIA TEST NO. 643
TABLE B-VI
SUMMARY OF LABORATORY CHLORIDE ION CONTENT TEST RESULTS
CALIFORNIA TEST NO. T 291
TABLE B-VII
SUMMARY OF LABORATORY RESISTANCE VALUE (R-VALUE) TEST RESULTS
ASTM D 2844
(ieocon Project No. G1928-52-02 - B-2 - August 29. 2019
PROJECT NO. G1928-52-01
SAMPLE NO. B5-4
-6
-4
-2
0
10
12
1 10 100
APPLIED PRESSURE (ksf)
Initial Dry Density (pcf) 116.4 d I Initial Saturation (%) 84.2
Initial Water Content (%) 13.5 1 Sample Saturated at (ksf) 2.0
CONSOLIDATION CURVE
VIASAT
BRESSI RANCH
CARLSBAD, CALIFORNIA
6 1925-52-0 1 GPJ
Figure B-4
GEOCON
APPENDIX
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
VIASAT BRESSI RANCH - PHASE 5
CARLSBAD, CALIFORNIA
PROJECT NO. G1928-52-02
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon. The recommendations contained
in the text of the Geotechnical Report are a part of the earthwork and grading specifications
and shall supersede the provisions contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
GI rev. 07/2015
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than
12 inches in maximum dimension and containing at least 40 percent by weight of
material smaller than % inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than
4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than
12 inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than 3/4 inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
GI rev. 07/2015
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal: vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition.
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1'/2 inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
Geocon and the property owner. Concrete fragments that are free of reinforcing steel may
be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this
document.
GI rev. 07/2015
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Finish Grade A —Original Ground
2
Finish Slope Surface
Remove All
Unsuitable Material
As Recommended By Slope To Be Such That Consultant Sloughing Or Sliding
Varies Does Not Occur
"B"
See Note 1 See Note 2
No Scale
DETAIL NOTES: (1) Key width "B' should be a minimum of 10 feet, or sufficiently wide to permit
complete coverage with the compaction equipment used. The base of the key should
be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material
and at least 2 feet into dense formational material. Where hard rock is exposed in the
bottom of the key, the depth and configuration of the key may be modified as
approved by the Consultant.
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
GI rev. 07/2015
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
GI rev. 07/2015
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
GI rev. 07/2015
6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
GI rev. 07/2015
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of "passes" have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for "piping" of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. SUBDRAINS
7.1 The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
GI rev. 07/2015
TYPICAL CANYON DRAIN DETAIL
NATURAL CI1C - - -
ALLLMLIMMM
COLLUMUM
BEDROCK
SEE OBTAL BELOW
NOTE FINAL W OF MEAT OUTLET
SMALL BE I80NORATEO.
V DIA. PERFORATED
S&DRAJN PIPE
9 CUBIC FEET! FOOT OF OPEN
GRADED GRAVEl. SOUNDED BY
MIRAF1 I4CNC (OR EQUIVALEN1)
FILTER FABRIC
NOTES:
84NCH DIAMETER, SCHEDULE 80 PVC PERFORATED PIPE FOR FILLS
IN EXCESS OF 100-FEET IN DEPTH OR A PIPE LENGTH OF LONGER THAN 500 FEEL
2......8-INCH DIAMETER SCHEDULE 40 PVC PERFORATED PIPE FOR FILLS
LESS THAN 100-FEET IN DEPTH OR A PIPE LENGTH SHORTER THAN 500 FEET.
NO SCALE
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
GI rev. 07/2015
TYPICAL STABILITY FILL DETAIL
SEE YUIP
UN SEE NOTE
FORMATIONAL
MATERIAL
EXCAVATE UcKCLrI AT 1:1 INCLINATION (UNLESS OThERWBIE NOTED).
2.....BABE OF STABILITY FILL TO BE 3 FEET INTO FORMATIONAL MATERIAL ELOPING A MINIMUM 5% INTO SLOPE.
3....STABIIJTY FILL TO BE COMPOSED OF PROPERLY CCWACTB) GRANULAR SOIL
4....CHIMNEY DRAINS TO BE APPROVED PREFABRICATED CHIMNEY DRAIN PANELS (MIACRAJN 6204 OR EJIVALEN1)
SPACED APPROXIMATELY 20 FEET CENTER TO CENTER AND 4 FEET WIDE. CLOSER RACING MAYBE REQUIRED F
SEEPAGE IS EtICOIJNTERED.
5....FILTER MATERIAL TO BE 3M-14CH, OPEN-GRADED CRUSHED ROCK ENCLOSED IN APPROVED FLTER FABRIC (MIRAFI 140140).
8.....COU.ECTOR PIPE TO BE 4-INCH MINNUM DIAMETER, PERFORATED. THICK-WALLED PVC SCHEIXA.E 40 OR
EQUIVALENT, AND SLOPED TO DRAIN AT 1 PERCENT IUNMUM TO APPROVED OUTLET.
NO SCALE
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
GI rev. 07/2015
I /
7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
FRONT VIEW
NO SCALE
SIDE VIEW
CMCWTE
CUT.OFFWLi
SCUD SUBDRAIN PE PSRFORATSC 6016N PIPE
J PMIN.
NO SCALE
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
GI rev. 07/2015
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
1
I
TYPICAL HEADWALL DETAIL
FRONT VIEW
ORr
,P
J
Ii.
iS *.
d
.O SCALE
SIDE
NOTE: HEADWALL SHOULD OUTLET AT TOE OF FILL SLOPE NO SCALE
OR INTO CONTROLLED SURFACE DRAINAGE
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an "as-built" map Showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain. The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
GI rev. 07/2015
8. OBSERVATION AND TESTING
8.1 The Consultant shall be the Owner's representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
8.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
8.5 We should observe the placement of subdrains, to check that the drainage devices have
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method
GI rev. 07/2015
r
8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and I Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density I Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
1 8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9.
PROTECTION OF WORK
9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
9.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
10. CERTIFICATIONS AND FINAL REPORTS
I 10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
I elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
I of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
10.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
I that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications
I
I
11 GI rev. 07/2015
LIST OF REFERENCES
2016 California Building Code, California Code of Regulations, Title 24, Part 2, based on the
2015 International Building Code, prepared by California Building Standards Commission,
dated July, 2016.
2. American Concrete Institute, ACI 318-11, Building Code Requirements for Structural
Concrete and Commentary, dated August, 2011.
American Concrete Institute, ACI 330-08, Guide for the Design and Construction of Concrete
Parking Lots, dated June, 2008.
4. American Society of Civil Engineers (ASCE), ASCE 7-10, Minimum Design Loads for
Buildings and Other Structures, Second Printing, April 6, 2011.
Boore, D. M., and G. M Atkinson (2006), Ground Motion Prediction Equations for the
Average Horizontal Component of PGA, PVG, and 5%-Ramped PSA at Spectral Periods
Between 0. Ols and 10. Os, Earthquake Spectra, Vol. 24, Issue 1, February 2008.
California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic
Hazard Assessmentfor the State of California, Open File Report 96-08, 1996.
California Geological Survey, Seismic Shaking Hazards in California, Based on the
USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April
2003). 10% probability of being exceeded in 50 years.
&0:1/redirect. conservation. ca.gov/cgs/rghm/pshamap/pshamain. html
Campbell, K. W., Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean
Horizontal Component of PGA, PG V, PGD and 5% Damped Linear Elastic Response Spectra
for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication in the
NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, February
2008.
Chiou, Brian and Robert R. Youngs, A NGA Model for the Average Horizontal Component of
Peak Ground Motion and Response Spectra, preprint for article to be published in NGA
Special Edition for Earthquake Spectra, Spring 2008.
County of San Diego, San Diego County Multi Jurisdiction Hazard Mitigation Plan, San
Diego, California - Final Draft, dated July, 2010.
11.. Geocon Incorporated (2015), Geotechnical Investigation, Viasat, Bressi Ranch, Carlsbad,
California, dated July 5, 2016 (Project No. G1928-52-01).
Historical Aerial Photos. http://www.historicaerials.com
Jennings, C. W., 1994, California Division of Mines and Geology, Fault Activity Map of
California andAdjacent Areas, California Geologic Data Map Series Map No. 6.
Kennedy, M. P. and S. S. Tan, 2008, Geologic Map of the San Diego 30 'x60' Quadrangle,
California, USGS Regional Map Series Map No. 3, Scale 1:100,000.
Geocon Project No. G 1928-52-02 August 29, 2019
LIST OF REFERENCES (Concluded)
Leighton and Associates, Inc. (2004), Addendum to the As-Graded Reports of Mass Grading
Concerning the Completion of Settlement Monitoring, Planning Areas PA-1 through PA-5,
Bressi Ranch, Carlsbad, California, dated October 11, 2004 (Project No. 971009-014).
Leighton and Associates, Inc. (2011), Geotechnical Update Study, Bressi Ranch Industrial
Planning Area 2, Carlsbad, California, dated April 12, 2011 (Project No. 971009-065).
Pasco Laret Suiter & Associates (2017), Grading Plans For: Viasat Bressi Ranch, Drawing
No. 4974A, Carlsbad, California, approved January 1, 2017.
Pasco Laret Suiter & Associates (2019), Minor Site Development Plan for: Viasat Bressi
Ranch - SDP Minor Lot 3, Buildings 16-1 7 and Parking Structure, Carlsbad, California,
dated August 19, 2019.
Risk Engineering, EZ-FRISK, 2016.
Christian Wheeler Engineering (2019), As-Graded Geotechnical Report, Viasat Bressi Ranch
Campus, Gateway Road, Carlsbad, California, dated May 31, 2019 (Project No. 2170158.26).
Special Publication 117A, Guidelines For Evaluating and Mitigating Seismic Hazards in
California 2008, California Geological Survey, Revised and Re-adopted September 11, 2008.
Unpublished reports, aerial photographs, and maps on file with Geocon Incorporated.
USGS computer program, Seismic Hazard Curves and Uniform Hazard Response Spectra,
http://geohazards. usgs.zov/designmaps/us/application.php.
Geocon Project No. Gl928-2-O2 August 29. 2019