HomeMy WebLinkAbout567 Airport Boulevard - Technical Study (4),■� ROMIC
� E N G I N E E R S
�����EI�HNI�.�L IN�`�S`�IGA��ON
BURLINGAME BAY OFFICE BUILDING AND PARKING
STRUCTURE
555 & 577 AIRPORT BOULEVARD
BURLINGAME, CALIFORNIA
Prepared for
EW-PG Airport Owner, LLC
c/o EverWest Advisor, LLC
1099 18th Street, Suite 2900
Denver, Colorado 80202
April 2020
a..� � r �v� �. �..�
Project No. 5047-1 , � o �,; ;� ;20
° _�; .iGAME
' ``�:.L�.Ni.iING �IV
� ROMIG
� ENGINEERS
April 21, 2020
5047-1
�
EW-PG Airport Owner, LLC
c/o EverWest Advisor, LLC
1099 18t" Street, Suite 2900
Denver, Colorado 80202
RE: GEOTECHNICAL INVESTIGATION
OFFICE BUILDING AND
PARKING STRUCTURE
555 & _577 AIRPORT BOULEVARD
BURLINGAME, CALIFORNIA
Gentlemen:
t.
In accordance with your request, we have performed a geotechnical investigation for the
proposed office building and parking structure to be constructed at 555 and 577 Airport
Boulevard in Burlingame, California. The accompanying report summarizes the results
of our field exploration, laboratory testing, and engineering analysis, and presents our
geotechnical recommendations for the project.
We refer you to the te�:t of our re}�ort for specilic recommendations. Thank you for the
opportunity to work ��ith you on this project. If you have any questions or comments
about our tindings or reco�nrnendations for the project, please call.
�
Very truly yours,
ROMIG ENGINEERS,
J'/S J. OTT\
�GP� e0
v y
��"�'� #
Lucas J. Ottoboni, P.E. �
�
�X\
Glenri A. Rom
�OQROFESS/pNq
�Q ���N� A RO �, �y�
��
� 002157 ''
�r c
F � �
i �l'y �TECHN�G a�Q,
�. , � CALIFO�
No.84234 �
� ,t /
Copies: Addressee (l+via email)
DES Architects and Engineers (via email)
Attn: Mr. Kenny Hung
�
�
�
r
1390 EI Camino Real, Second Floor � San Carlos, CA 94070 �(650) 591-5224 � www.romigengineers.com
GEOTECHNICAL INVESTIGATION
OFFICE BUILDING AND PARKING STRUCTURE
555 & 577 AIRPORT BOULEVARD
BURLINGAME, CALIFORNIA 94010
PREPARED FOR:
EW-PG AIRPORT OWNER, LLC
c/o EVERWEST ADViSOR, LLC
1099 18TH STREET, SUITE 2900
DENVER, COLORADO 80202
PREPARED BY:
ROMIG ENGINEERS, INC.
1390 EL CAMINO REAL, SECOND FLOOR
SAN CARLOS, CALIFORNIA 94070
APRIL 2020
,ROMIG
E N G I N E E R S
�
TABLE OF CONTENTS
Letter of transmittal
Page No.
Cover Page
TABLE OF CONTENTS
INTRODUCTION.........................................................................................................1
ProjectDescription ................................................................................................1
Scopeof Work .......................................................................................................1
Limitations.............................................................................................................2
SITE EXPLORATION AND RECONNAISSANCE ...................................................3
SurfaceConditions ................................................................................................3
Subsurface C:onditions ...........................................................................................3
GroundWater ........................................................................................................4
Corrosion Potential Testing ...................................................................................5
GEOLOGICSETTING .................................................................................................5
Faultingand Seismicity .........................................................................................6
Table 1. Earthquake Magnitudcs and Historical Carthquakes .....................7
Earthquake Design Parameters ..............................................................................7
Table 2. 2019 CBC Seismic Design Criteria ...............................................8
� LIQUEFACTION (SEISMIC: SETTLEMENT) ............................................................8
Table 3. Results of Liquefaction Evaluation ................................................9
STATIC' SETTLEMENT .............................................................................................10
Static Settlement due to Fill Placed at the Site ....................................................10
Table 4. Estimated 30-Year Consolidation Settlement Fill Placement......10
GeologicHazards ................................................................................................1 1
CONCLUSIONS..........................................................................................................12
Pile Foundation Considerations ...........................................................................12
Building Floor Types and Static Settlement Considerations ...............................13
Ground Water and Corrosion Concerns ..............................................................13
PILEFOUNDATIONS ................................................................................................14
EndBearing Piles ................................................................................................14
FrictionPiles ........................................................................................................15
Table 5. Reduction Factors fior Axial Friction Capacity in Various Pile
Uroups.........................................................................................................16
Pile Foundation Settlement ..................................................................................16
Lateral Loads on Piles and Pile Caps ..................................................................17
Table 6. Average P-Multipliers for Various Pile Groups ...........................17
Indicator Program for Driven Pre-Cast Concrete Piles .......................................18
PDA Monitoring for Driven Pre-Cast Concrete Piles .........................................19
WEAP Analysis tor Driven Pre-Cast Concrete Piles ..........................................19
Pre-Drilling for Driven Pre-Cast Concrete Piles .................................................19
Load Testing for Auger Cast Piles ......................................................................20
Auger Cast Pile Installation .................................................................................20
SPREAUFOOTINGS .................................................................................................20
Lateral Loads for Shallow Foundations ..............................................................21
Settlement for Shallow Foundations ...................................................................21
,ROMIG
E N G 1 N E E R S
TABLE OF CONTENTS
(Continued)
ELEVATOR PIT RETAINING WALLS ....................................................................22
SLAI3S-ON-GIZADE ...................................................................................................22
General Slab Considerations ...............................................................................22
ExteriorFlatwork .................................................................................................23
StructuralSlabs ....................................................................................................23
At-grade Interior Slabs ........................................................................................24
VEHICLE PAVEMENT ..............................................................................................25
Table 7. Minii��um Asphalt Conerete Pavement Section Thicknesses ......25
RigidConcrete Pavements ..................................................................................26
Table 8. Rigid Concrete Pavement Design .................................................26
EARTHWORK............................................................................................................27
Clearing and Subgrade Preparation .....................................................................27
Re-use of E�isting Concrete and Aggregate Base and Subbase ..........................27
Flexible Connections for Underground Utilities .................................................27
Bay Mud Considerations .....................................................................................27
Utility Trench Backtill ........................................................................................28
Temporary Dewatering For Excavations .............................................................28
Temporary Slopes and Excavations ....................................................................29
MaterialFor Fill ..................................................................................................30
Compaction..........................................................................................................30
Table 9. Compaction Recommendations ...................................................30
Pern�anent Slopes ................................................................................................31
SurfaceDrainage .................................................................................................31
FUTURE SERVICES ..................................................................................................31
PlanReview .........................................................................................................31
Construction Observation and Testing ................................................................32
REFERENCES
FIGURE 1 - VICINITY MAP
FIGURE 2 - SITE PLAN
FIGURE 3- VICINITY GEOLOGIC MAP
FIGURE 4- CONTOUR MAP OF �AY MUD THICKNESS
FIGURE 5- REGIONAI, FAULT AND SEISMICITY MAP
APPENDIX A - FIELD INVESTIGATION
Figure A-1 - Key to Exploratory Boring Logs
Exploratory Boring Logs EB-1 and EB-2
Cone Penetration Tests CPT-1 through CPT-7
Shear Wave Velocity with Depth: CPT-02, CPT-04, and CPT-07
,ROMIG
E N G 1 N E E R S
TABLE OF CONTENTS
(Continued)
APPENDIX B- SUMMARY OF LABORATORY TESTS
Figure B-1 - Plasticity Chart
Figure B-2 - Consolidation Test
Figure F3-3 - R-Value Test Report
Figure B-4 - Corrosivity Test Summary
APPENDIX C- PILE CAPACITY ANALYSES
Figure C-1 - Allow Capacities for 14" Square PCPS Pile
Figure C-2 - Allow Capacities for 16" Auger Cast Pile
Figure C-3 - Lateral Deflection Curves, Free Head Condition, 14" Pile
Figure C-4 - Bending Moment Curves, Free Head Condition, 14" Pile
Figure C-5 - Shear Curves, Free Head Condition, 14" Pile
Figure C-6 - Lateral Deflection Curves, Fixed Head Condition, 14" Pile
Figure C-7 - Bending M�ment Curves, Fixed Head Condition, 14" Pile
Figure C-8 - Shear Curves, Fixed Head Condition, 14" Pile
Figure C-9 - Lateral Deflection Curves, Free Head Condition, 16" Pile
Figure C-10 - Bending Moment Curves, Free Head Condition, 16" Pile
Figure C-11 - Shear Curves, Free Head Condition, 16" Pile
Figure C-12 - Lateral Deflection Curves, Fixed Head Condition, 16" Pile
Figure C-13 - Bending Moment Curves, Fixed Head Condition, 16" Pile
Figure C-l4 - Shear Curves, Fixed Head Condition, 16" Pile
APPENDIX D - LIQUEFACTION ANALYSES
Figure D-1 - Liquefaction Analysis Using Robertson 2009
Figure D-2 - Liyuefaction Analysis Using Boulanger & Idriss 2014
Figure D-3 - Liquefaction Analysis Using Moss et. al 2006
�
�
,
,
�
�ROMIG
E N G I N E E R S
J
��
GEOTECHNICAL INVESTIGATION
FOR
OFFICE BUILDING AND PARKING STRUCTURE
555 & 577 AIRPORT BOULEVARD
BURLINGAME, CALIFORNIA
INTRODUCTION
This report presents the results of our geotechnical investigation for the proposed office
building and parking structure to be constructed at 555 and 577 Airport Boulevard in
Qurlingame, California. The location of the site is shown on the Vicinity Map, Figure 1.
The purpose of this investigation was to evaluate subsurface conditions at the site and to
provide geotechnical recommendations for the project.
Proiect Description
We understand that the project consists of constructing an 8-story (above-grade) office
i building and a 4- to 5-story at-grade parking garage structure at the referenced site in
Burlingame. The proposed office building is expected to have a footprint of about 30,000
square feet, and will be located between the two eaisting buildings at 555 and 577 Airport
f3oulevard. The parking structure will bc located north of the building in lhe existing
asphalt parking area. The locations of the proposed office building and parking structure
are shown on the attached Site Plan, Figure 2. Based on our discussion with the project
teain, we understand that the office building will likely be of steel frame construction.
Expected Grading at the Parking Garage: The site elevations range from about 4.5 to 7
feet (project datum) in the area of the parking garage and the finished floor is expected to
be 6 feet. This will require up to about 1 to 1.5 feet of iill to reach the bottom oi� the slab
(assuming a 6 inch slab).
Expected Grading at the Office Building: The site elevations range from about 5 to 9 feet
(project datu�n) in the area of the office building and the tinished floor is expected to be
12 feet. This will require about 2.5 to 6.5 feet of till to reach the bottom of the slab
(assutning a 6 inch slab).
Scope of �'�'ork
The scope of wark of this investigation was presented in detail in our agreement with
EW-PG Airport Owner, LLC c/o EverWest Advisor, LLC dated July 30, 2019. In order
to accomplish our investigation, we performed the following work.
,ROMIG
ENGINEERS
Burlingame Bay Office Building and Parking Structure Page 2 of 32
• Review of geologic and seismic conditions in the site vicinity and evaluation of the
potential for geologic hazards to impact the site.
• Subsurface exploration consisting of drilling, sampling, and logging of two
exploratory borings and seven cone penetration tests (CPT) in the area of the
proposed structures.
• Laboratory testing of selected samples to aid in soil classification and to help evaluate
their engineering properties.
• En�ineering analysis and evaluation of the subsurface and laboratory data to develop
geotechnical design criteria for the project.
• Preparation of this report presenting our recommendations for the proposed
construction.
Limitations
This report has been prepared for the exclusive use of EW-PG Airport Owner, LLC c/o
EverWest Advisor, LLC for specific application to the proposed oftice building and
parking structure to be constructed at 555 and 577 Airport E3oulevard in Rurlingame,
California. We make no warranty, expressed or implied, for the services we performed
for this project. Our services were performed in accordance with geotechnical
engineering principles generally accepted at this ti�ne and location. This report was
prepared to provide engineering opinions and recc�mmendations only. in the event there
are any changes in the nature, design or location of the project, or if any future
improvements are planned, the conclusions and recommendations contained in this report
should not be considered valid unless 1) the project changes are reviewed by us, and 2)
the conclusions and recommendations presented in this report are modified or verified in
writing.
The analysis, conclusions, and recom�nendations presented in this report are based on site
conditions as they existed at the time of our investigation; the currently planned
iinprovements; review of readily available reports relevant to the site conditions; and
laboratory test results. In addition, it should be recognized that certain limitations are
inherent in the evaluation of subsurface conditions, and that certain conditions may not be
detected during an investigation of this type. Changes in the information or data gained
.
from any of these sources could result in changes in our conclusions or recommendations.
If such changes occur, we should be advised so that we can review our report in light of
those changes.
�ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 3 of 32
SITE EXPLORATION AND RECONNAISSANCE
Our site reconnaissance and subsurface exploration were performed on February 11, 12,
and 13, 2020. Our subsurface exploration consisted of advancing two exploratory
borings to a depth of about 50 feet and seven CPTs to depths ranging from about 55 to 85
feet. The exploratory borings were advanced using a truck-mounted drill equipped with
8-inch dia�neter hollow-stem augers and an automatic trip hammer, and the CPTs were
advanced using an electronic cone penetration test (CPT) system, which was mounted on
a truck having a down pressure capacity of 20 tons. The approximate locations of the
borings and CPTs are shown on the Site Plan, Figure 2. The boring and CPT logs are
attached in Appendix A, and the results of our laboratory tests are attached in Appendix
B.
Surface Conditions
The site is located in a co�nmercial area along the southeast side of Airport Boulevard,
north of the Burlingame Lagoon and west of the Sanchez Channel. At the time of our site
� reconnaissance, the approximately 12-acre sile was occupied by an 8-story office
building located at the southwest corner of the site and a 5-story office building located at
the southeast corner of the site. Asphalt concrete drive aisles and parking areas occupied
the remainder of the site. The relatively flat site was landscaped with lawn grass, shrubs,
and small to large trees. Based on our brief observation irom the exterior, the buildings
at the property generally were not observed to have obvious signs of significant distress.
The asphalt concrete pavement and concrete flatwork around the buildings generally
appeared to be in good condition witl� some l��cali�eci cracks up to about 1/8-inch.
We understand that the existing building with the address of 555 Airport Boulevard is
constructed on 12-inch square precast concrete piles about 50 feet deep and the ground
floor is constructed with a 10-inch structural slab. The existing building at 577 Airport
Boulevard is also constructed on 12-inch square precast concrete piles with a 6-inch thick
reinforced slab-on-grade.
Subsurface Conditions
At the locations of our exploratory borings and CPTs, we generally encountered about 6
to 10 feet of till composed of clayey sand to sandy lean clay of low to moderate plasticity
underlain by 2 to 4 feet of soft Younger Bay Mud of high plasticity. Beneath the Bay
Mud we encountered interbedded layers of inedium dense to very dense sands and stiff to
very stiff lean clay of low to moderate plasticity.
�
,ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 4 of 32
A Liquid Limit of 66 and Plasticity Index of 36 were ineasured on one sample of
Younger Bay Mud retrieved from Boring EB-1, indicating a high plasticity. A Liquid
Limit of 48 and Plasticity Index of 27 were measured on a sample of very stitf clay at a
depth of about 20 feet, indicating a moderate to high plasticity.
We note that fill is often variable by nature and it is possible that some areas of the fi11
may have moderate to high plasticity and a moderate to high potential for expansion. We
also note that the Bay Mud is soft and highly compressible under new fill and building
loads, which is discussed later in this report.
In addition, portions of the sands encountered at various depths across the site appeared
to be susceptible to liquefaction. Details of our liquefaction evaluation are included in
the section below titled "Liyuefaction Evaluation."
Ground Water
Ground water was encountered in our borings during drilling and sampling at a depth of
approximately 19.5 to 20 feet. Because of the low penneability of the Bay Mud and the
hollow-stem augers used during subsurface exploration, the observed ground water level
did not appear to repi-esent the stabilized ground water level. In the CPTs, pore pressure
dissipation tests and ground water ineasurein�nts ranged from 2.8 to 12.2 feet. Sii�ce the
CPTs were advanced over a ri�o day period and at different times during the day, it is
likely that the relatively large fluctuation was at least partially due to tidal fluctuations
and the proximity to the San Francisco Bay.
Information presented in Seismic Hazard Zone Report 113 for the San Mateo 7.5-Minute
Quadrangle (California Geological Survey, 2018) indicates the depth to the historic high
ground water level in the area is less than 10 feet.
Based on our review of the CPT and boring data from the nearby geotechnical
investigation performed by Treadwell & Rollo at 300-333 Airport Boulevard, ground
water was encountered at depths rangin� between 1 and 5.2 feet below the ground
surface.
Based on the tindings from this investigation, the relatively low site elevation and
proximity to the Bay, the highest projected future ground water depth is estimated to be
approximately 1 foot below the existing ground surface at the site.
,ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 5 of 32
Corrosion Potential Testin�
Corrosion potential tests were performed by Cooper Testing Laboratory on one sample of
soil from Boring EB-1 between depths of about 3 to 5 feet. The soil sample was tested
for resistivity, pH, sulfate content, chloride content, and redox potential. The results of
these tests are presented in Appendix B.
The water-soluble sulfate content of the sample that was tested in accordance with
Califc�rnia Test Method 4327-modifed was ineasured to be about 756 mg/kg (parts per
million, ppm), and up to about 0.0756% by dry weight. ACI 318 classifies a water-
soluble sulfate content of 0.0 to 0.10% by dry weight as producing negligible sulfate
exposure to concrete.
Resistivity of the lab-saturated soil sample measured in accordance with ASTM Test G57
was measured to be about 1,165 ohm-cm. ASTM STP 1013 titled "Effects of Soil
Characteristics on Corrosion" indicates soil resistivity below 2,300 ohm-cm would
classify soil as severely corrosive.
The pH value of the soil sample was measured to be about 7.8. Chloride content was
measured to be about 116 ing/kg (ppm), and the oxidation-reduction potential (Redox)
was measured to be about 311 mv.
Please note that the above corrosion evaluation should be considered preliminary. For
specitic long-term corrosion control design recommendations, a corrosion engineer
should be retained to evaluate the corrosion potential and protection for buried �netal and
concrete elements.
GEOLOGIC SETTING
As part of our investigation, we reviewed our local experience and geol�gic literature
pertinent to the general area of the site. The infonnation reviewed indicates the site is
located in an area underlain by artificial fill, Qfi, (Panlpeyan, 1994). The till is expected
to consist priinarily of poorly consolidated to well consolidated gravel, sand, silt and rock
fragments in various combinations. Based on our site exploration, the fill across the site
is approximately 6 to 10 feet thick. The geology of the site vicinity is shown on the
Vicinity Geologic Map, Figure 3.
�
�
,ROMIG
ENGINEERS
Burlingame Bay Office Building and Parking Structure Page 6 of 32
f3ased on infornlation presented in the map titled "Map Showing Thickness of Younger
Bay Mud, Southern San Francisco Bay" (McDonald, Nichols, Wright, and Atwater,
] 978), the site is mapped in an area underlain by about 5 feet of co�npressible Younger
Bay Mud. The estimated extent and thickness of the Youn�er Bay Mud in the ilnmediate
site area is shown on the Contour Map of Bay Mud Thickness, Figure 4.
The Seismic Hazard Zones Map of the San Mateo Quadrangle prepared by tlle California
Ueological Survey in 2018 indicates that the site is located in an area that may be
underlain by soils pc�tentially susceptible to liquefaction during a major earthquake. A
discussion on the potential for liquefaction at the site is presented later in this report.
The lot and the immediate site vicinity are located in an area that slopes down very gently
to the north toward the San Francisco Bay. The site is located at an elevation of
approximately 4 to 9 feet above sea level.
Faultin� and Seismicity
There are no mapped through-going faults within or adjacent to the site and the site is not
located within a State of California Earthquake Fault Zone (formerly known as a Special
Studies Zone), an area where the potential for fault rupture is considered probable. The
closest active fault is the San Andreas fault, located approximately 3.4 miles southeast of
the property. Thus, the likelihood of surface rupture occurring from active faulting at the
site is lo���.
The San Francisco Bay Area is, however, an active seismic region. Earthquakes in the
region result from strain energy constantly accumulating because of the northw�estward
moveinent of the Pacific Plate relative to the North American Plate. On average about
].6-inches of �Y�ovement occur per year. Historically, the Bay Area has experienced
large, destructive earthquakes in 1838, 1868, 1906 and 1989. The faults considered most
likely to produce large earthquakes in the area include the San Andreas, San Gregorio,
Hayward, and Calaveras faults. The San Gregorio fault is located approximately 9.8
miles southwest of the site. The Hayward and Calaveras faults are located approximately
15 and 23 �niles northeast of the site, respectively. These faults and significant
earthquakes that have been documented in the Bay Area are listed in Table 1 on the
following page, and are shown on the Regional Fault and Seismicity Map, Figure 4.
,ROMIG
E N G 1 N E E R S
�_
Burlingame Bay
Office Building and Parking Structure
Page 7 of 32
Table 1. Earthquake Magnitudes and Historical Earthquakcs
Burlingame Bay Office Building and Parking Structure
Burlingame, California
Maximum Historical Estimated
Fault Magnitude (Mw) Earthquakes Magnitude
San Andreas 7.9 1989 Loma Prieta 6.9
1906 San Francisco 7.9
1865 N. of 1989 Loma Prieta Earthquake 6.5
1838 San Francisco-Peninsula Segment 6.8
1836 East of Monterey 6.5
Hayward 7.1
Calaveras 6.8
San Gregorio 7.3
1868 Hayward
1858 Hayward
1984 Morgan Hill
1911 Morgan Hill
1897 Gilroy
1926 Monterey Bay
.
�.
..
62
6.2
6.3
6.1
In the future, the subject property will undoubtedly experience severe ground shaking
during moderate and large magnitude earthquakes produced along the San Andreas fault
or other active Bay Area fault zones. Using infonnation from recent earthquakes,
improved �napping of active faults, ground motion prediction modeling, and a new model
for estitnating earthquake probabilities, a panel of experts convened by the U.S.G.S. have
concluded there is a 72 percent chance for at least one earthquake of Magnitude 6.7 or
larger in the �3ay Area before 2043. The Hayward fault has the highest likelihood, of an
earthyuake greater than or equal to magnitude 6.7 in the Bay Area, esti�nated at 33
percent, while the likelihood on the San Andreas and Calaveras faults is estimated at
approximately 22 and 26 percent, respectively (Aa�aard et al, 2016).
�
Earthquake Design Parameters
�
The State of California currently requires that buildings and structures be designed in
accordance with the seismic design provisions presented in the 2019 California Building
Code and in ASCE 7-16, "Minimum Design Loads for Buildings and Other Structures."
Based on site geologic conditions and the average shear wave velocity measured in CPT-
02 (1,406 ft/s in upper 60 feet), CPT-04 (1,256 ft/s in the upper 85 feet), and CPT-07
(1,269 ft/s in the upper 55 feet), the site may be classified as Site Class D, very dense
soil and soft rock, in accordance with Chapter 20 of ASCE 7-16. Spectral Response
Acceleration parameters and site coefficients may be taken directly from the U.S.G.S.
website based on the longitude and latitude of the site. For site latitude (37.7929),
longitude (-122.4357) and Site Class D, design parameters are presented on Table 2 on
the following page.
�ROMIG
ENGINEERS
Burlingame Bay Office Building and Parking Structure Page 8 of 32
Table 2. 2019 CBC Seismic Design Criteria
Burlingame Bay Office Building and Parking Structure
Burlingame, California
Spectral Response
Acceleration Parameters
Mapped Value for Short Period - SS
Mapped Value for 1-sec Period - S i
Site Coefticient - Fa
Site Coefticient - F�.
Adjusted for Site Class - SMs
Adjusted for Site Class - SM�
Value for Design Earthyuake - Sns
Value for Design Earthquake - S�>>
Desi�n Value
1.500
0.60
1.0
1.7*
1.500
1.020*
1.000
0.68*
* The values of F�, S�,�, and S„� above are provided fior calculation of
Ts. A site-specific ground motion hazard analysis may be required
unless the exceptions in ASCE 7-16 Section 11.4.8 apply to the
project.
LIQUEFACTION (SEISMIC SETTLEMENT)
To evaluate the potential for earthyuake-induced liyuefaction of the soils at the site, w�e
perf��nned a liquefiaction analysis of the CPT data using the program CLiq, developed by
GeoLogismiki. The progra�n applied several published methodologies, including
Roberston 2009, Idriss and 13oulanger 2014, and Moss et. al 2006, ���hich uses a
weighting factor on vertical strains with depth, per Cetin et al 2009; each of these
methodologies were assigned a one-third probability of occurrence.
The silty sand, sandy silt, and clayey silt to silty clay strata that we encountered at the site
below the highest projected ground water depth of 1 foot w�as considered in our
liquefaction analysis.
The results of our analysis indicate that soine of the interbedded silty sand, sandy silt, and
clayey silt to silty clay strata encountered in our CPT's could liyuefy when subjected to a
peak ground acceleration (PGA) of 0.802g, the PGAm for the maximum considered
earthyuake based on ASCE 7-16. The results of our liquefaction evaluation of'the CPT
data are presented in Table 4, and are presented in Figures D-1 through D-3 in Appendix
D.
,ROMIG
ENGINEEFiS
Burlingame Bay Office Building and Parking Structure Page 9 of 32
Table 3. Results of Liquefaction Evaluation
Burlingame Bay Office Building and Parking Structure
Burlingame, California
Robertson 2009 Idriss and Boulanger 2014 Moss et. al 2006 Estimated
CPT No.
Settlemeut (Inches) Settlement (Inches) Settlement (Inches) Settlement (Inches)
CPT-O 1 0.6 1.1 1.4 1.0
CPT-02 0.4
CPT-03B 1.0
CPT-04A 0.3
CPT-OS 0.6
CPT-06 1.0
CPT-07 1.2
1.0
2.0
0.8
1.4
1.6
1.7
1.0
2.0
0.8
1.2
1_7
1.6
1:
�
1�
�
�
�
Based on our analyses of the CPT data, total settlement that could occur at the ground
surface as a result of liquefaction from the design-level earthquake is estin�ated to range
� from approximately 0.6 to 1.7 inches, varying primarily with the analysis inethods used
and uncertainties with regard to the character of the clay fraction present in soils.
�
However, in our opinion, differential settlement on the order of about =�/4- to 1'/4-inch over
a horizontal distance of 50 feet is possible from liquefaction at the ground surface during
seismic shaking in areas of the site that are not directly supported on deep foundations.
This may require future maintenance ar releveling of some of the surface supported
improvements after an earthquake.
Lateral Spreading is generally caused by liquefaction of soils on gentle slopes, resulting
in predominately horizontal displacement and lateral extension of the soil mass
accompanied by shear and tensile cracking of the ground surface. Lateral spreading can
also occur on nearly flat-lying terrain where horizontal displacement takes place toward
an unsupported slope face such as a steep embankment. The majority of estimated
liquefaction settlement is expected to occur within the upper ] 0 feet and the liquefiable
strata did not appear to slope towards the open faces of Burlingame Lagoon and Sanchez_
Channel or be continuous across the site. Therefare, in our opinion, it is unlikely that
widespread lateral spreading would occur at the site. In our opinion, there is a potential
for some localized lateral spreading or ground displace�r�ents to occur towards or adjacent
to the open faces Burlingame Lagoon and Sanchez Channel during strong seismic
shaking. Since the structures will be supported on pile foundations, dynamic settlement
froin liquefaction and/or lateral displacements due to lateral spreading is not expected to
impact the building improvements.
,ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 10 of 32
STATIC SETTLEMENT
The compressible Younger Bay Mud ranged in thickness from about 2 feet to 4 feet
across the site and is expected to be compressible under new building and fill loads.
Static Settlement due to Fill Placed at the Site
Based on the current design finish floor elevation, about 1 to 1.5 feet of fill will be
required across the footprint of the parking structure and about 2.5 to 6.5 feet of fill ���ill
be required across the footprint of the oftice building. Fill placement with thicknesses
within this range are also expected around each of these structures to allow for
driveways, access, and civil site improvements. The results of our settlement evaluations
based on a Bay Mud thickness of 3 feet and the anticipated range of fill thicknesses are
presented in Table 4.
Table 4. Estimated 30-Year Consolidation Settlement Fill Placement
Burlingame Bay Office Building and Parking Structure
Burlingame, California
Loading Conditions Fill Loads Approximate 30-Year
(psfl Consolidation Settlement (inches)
0.5 feet of fill
1 feet of till
? feet of iill
3 feet of till
60
120
240
360
0.9
1.8
3.5
5.]
4 feet of fi ll
5 feet of fill
6 feet of fi 11
7 feet of till
480
600
720
840
6.7
8.2
9.7
1 1.2
About 90 percent of the total consolidation settlement esti�nated in Table 4 from new fill
loads are estimated to occur over a time period of about four to si?: months with some
remaining settlement occurring over a five year period.
�ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 11 of 32
Geologic Hazards
We briefly reviewed the potential for geologic hazards to impact the site, other than
liquefaction which was discussed previously, considering the geologic setting and the
soils encountered durin� our investigation. The results of our review are presented
below.
• Fault Rupture - The site is not located in a State of California Earthquake Fault
Zone or area where fault rupture is considered likely. Therefore, active faults
are not believed to exist beneath the site and the potential for fault rupture at the
site is considered low.
• Ground Shakin� - The site is located in an active seismic area. Moderate to
large earthquakes are probable along several active faults in the greater Bay
Area over a 30 to 50 year design life. Strong ground shaking should therefore
be expected several times during the design life of the developinent, as is typical
for sites throughout the Bay Area. The proposed structure should be designed
in accordance with current earthyuake resistance standards.
• Differential Compaction - Differential compaction can occur during moderate
and large earthquakes when unsaturated soft or loose, natural or till soils are
densified and settle, often unevenly across a site. Since the upper fill and native
soils encountered in our borings generally appeared to be dense sands and very
stiff to hard clay, which are typically not prone to large scale dyna�nic
densification, the likelihood of signiticant dynamic densitication affecting the
proposed and associated site improvements is relatively low provided the
recommendations presented in this report are followed during design and
construction. We note however that till soils are typically variable in nature and
portions of the fill may be soft/loose or expansive and may therefore experience
differential settlement which could damage pavement, slabs-on-grade and other
surface supported features.
• Tsunami Inundation - Areas mapped within a tsunami hazard zone inay be
affected by a series of waves or surges following a large earthquake in or along
the Pacific Ocean. According to the Tsunami Inundation Map for Emergency
Planning (CalEMA, 2009) for the San Mateo Quadrangle, the subject site is
]ocated immediately outside of the tsunami inundation area that encompasses
the Sanchez Channel and Burlingame Lagoon. We note that we have not
included modeling of tsunami events, tsunami forces on the buildings, and/or
the potential tsunami hazard risk at the subject site.
�
'ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 12 of 32
CONCLUSIONS
From a geotechnical viewpoint, the site is suitable for the planned development provided
the recommendations presented in this report are followed during design and
construction. Specific recommendations are provided in the following sections of our
report. The primary geotechnical concerns for the project are the:
1) The presence of variable undocumented fill overlying soft/compressible Bay
Mud;
2) Static ground settlement of Younger Bay Mud due to placement of fill (to raise
grades) at the site;
3) The presence and variability of an end bearing stratum across roughly the south
half of the site;
4) Presence of sand, silt, and silty clay strata that are susceptible to liquefaction-
induced settlements during seismic shaking;
5) The high current (2.8 feet) and projected (1 foot) ground water level at the site;
6) The high axial and lateral building loads associated with the structures;
7) The potential for severe gound shaking at the site during a major earthquake.
Pile Foundation Considerations
Since the buildings ��-ill have high structural loads and may have significant uplift load
demands, in our opinion, the buildings may be supported on a deep foundation system -
either driven pre-cast pre-stressed concrete piles or auger cast piles.
Due to the presence of a dense, approximately 20 fi��ot thick, and apparently continuous
sand strata encountered at depth of about 35 to 40 feet below the finish floor of the
planned oftice building at the south portion of the site, in our opinion, the oftice building
may be supported on end-bearing piles. For driven piles, we expect that the piles may
encounter refusal conditions about 5 to 10 feet into the dense portions of the sands. Due
to the variable depth, density and thickness of the strata, a signiticant variation in pile tip
elevations and need for pile cutoffs should be expected; the pile tip elevations and
consistency of the strata to support end bearing piles should be verified during the
indicator pile prograin. In our experience, it is inore difficult to verify the end bearing
capacity of auger-cast piles since the depth into the sand strata and density of the strata
are not as apparent during drilling/installation. If auger cast piles are selected, there may
be benefit in advancing additional CPT's across the structures to help establish pile tip
elevations and uniformity of the sand strata to support end bearing piles, or auger cast
friction piles could be considered.
�ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 13 of 32
The sand strata become thinner and less able to support end bearing piles, moving from
the south edge of the parking structure to the central and north portions. Where a
sufficiently thick and continuous end-bearing strata is not present, piles supporting the
parking structure should be designed as friction piles. Since dense sand strata that are too
thin to support end bearing piles were encountered in the central and north portion of the
parking structure, it may be difficult to drive piles through some of these layers and pre-
drilling of the piles at the parking structure to depths up to about 35 feet potentially may
be required to penetrate the upper sand strata and achieve full friction capacity. In this
respect, auger cast piles may be preferred at the parking structure.
The limitations and advantages of driven and auger cast piles with respect to the site
conditions should be carefully considered.
Buildin� Floor Tr'pes and Static Settlement Considerations
Based on the amount of fill and resulting large static settleinents at the office building, it
would be preferable to construct the oftice building floor as a structural slab designed to
span bet���een pile caps and to design conduits with flexible connections able to
acco�nmodate the amount of static ground settlement esti�nated. As an alternative, the
parking garage floor may be constructed as a slab-on-grade; however, it would be
advisable to place the fill required to raise grades directly beneath and slightly beyond the
parking gara�e footprint and leave the fill in place for at least 4 to 6�nonths prior to
construction of the slabs to allow time for the majority of the settlement to occur.
Ground Water and Corrosion Concerns
We note that ground water may rise up to about 1 to 3 feet below the ground surface.
The high ground water level �nay require dewatering during the pile cap, elevator pit
and/or utility trench excavations depending upon the excavation depths and the depth to
ground water at the time of construction. The timing and type of the dewatering
operation should be left to the contractor.
Based on the corrosion potential tests and our limited interpretation, soils and ground
water at the site may have a high potential far corrosioi� which may impact the
foundation and underground utility improvements. On a preliminary basis, all concrete
structures in contact w�ith the soils should be constructed using Type II cement with a
maximum water/cement ratio of 0.50. However, the structural criteria may result in more
stri��gent requirements. It would be beneficial to retain a corrosion engineer to further
evaluate and comment more specifically on the corrosion potential and protection for
buried metal and concrete elements.
�ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 14 of 32
Because subsurface conditions may vary from those encountered at the locations of our
borings and CPT's, and to observe that our recammendations are properly implemented,
we recom�nend that we be retained to 1) review the project plans for confonnance with
our recommendations and 2) observe and test during the earthwork and foundation
installation phases of construction.
PILE FOUNDATIONS
ln our opinion, the proposed buildings should be supported on a pile foundation system.
We understand that the pile types being considered are 14-inch syuare, precast,
prestressed (PCPS) concrete piles, and 16-inch diameter auger cast piles. As discussed
above, the piles supporting the ofrce building ��iay be designed as end bearing, whereas
the piles supporting the parking structure are e�pected to transition tro�n end bearing
piles at the south edge of the structure to friction piles going toward the north.
Due to the required place�nent of fill to achieve the building finished t7oor ele��ations and
the presence of compressible Bay Mud, Bay Mud settlement will occur and place a
do���ndrag load on the upper ] 3 feet of the piles. This is estimated based on the office
building tinished floor elevation of +12 feet and the average depth to the bottom of the
Bay Mud layer across the building footprint. The downdrag load is estimated to be 50
kips for 14-inch square PCPS piles and 16-inch diameter auger cast piles. The structural
engineer should contir►n that the total structural load on the piles plus the down drag load
will not exceed the structural capacity of the piles.
Dense to very dense sand strata were encountered in our borings and CPTs. These dense
strata may locally resull in hard or ref'usal driving conditions. In areas where hard driving
through sand strata is anticipated, it may be desirable to increase the effective prestress in
the piles to reduce the potential for damaging the piles during installation or it may be
required to pre-drill the upper portion of the piles. Due to the variable depth and density
of the sand strata, it is likely that so�ne piles will not be driven to their entire length and
pile cutoffs should be expected to provide the desired butt elevation.
End Bearin� Piles
In order to achieve significant end-bearing resistance, the piles should extend at least tive
ti�nes the diameter of the pile into the dense sand layer (or about 5 to 10 feet), or until
refusal conditions are encountered within the sands based on the criteria developed
during the indicatory pile driving. Based on our Borings and CPTs in the area of the
office building and south edge of the parking structure, we expect this will be achieved at
a tip elevation of about 45 to 50 feet below the finished floor elevation of the office
building (+12.0 feet using the site datum).
�ROMIG
ENGINEEFIS
Burlingame Bay Office Building and Parking Structure Page 15 of 32
The overall capacity for a 14-inch square concrete pile and/or 16-inch diameter auger cast
piles supporting the office building, adequately embedded into the dense sand strata
between a depth of about 35 to 40 feet, is anticipated to have an allowable capacity of
240 kips for dead plus live loads. The allowable pile capacity was calculated based a
factor of safety of about 2.0 for friction and 3.0 for end bearing. The axial capacity may
be increased by one-third when evaluating for total loads, including wind or seismic
forces. Where piles do not meet refusal or the driving criteria established during the
indicator pile program, or where the bcaring strata is too thin to consider end bearing
support, capacities should be determined as discussed the Friction Piles section below.
We note that the axial capacity of the pile may be increased by one-third when
considering additional short-term wind or seisnlic loading. The structural engineer
should continn that the total structural load on the piles plus the down drag load will not
exceed the structural capacity of the piles.
In our experience, due to the difficulty of identifying/verifying end bearing conditions of
auger cast piles, an expanded exploration and/or load test program may be required.
Friction Piles
As discussed previously, the sand strata become thinner and less able tc� support end
bearing piles, moving from the south edge of the parking structure toward the central and
north portions. Where a sufticiently thick and continuous end-bearing strata is not
present, piles supporting the parking structure should be designed as friction piles.
Sincc dense sand strata that are too thin to support end bearing piles were encountered in
the central and north portion of the parking structure, it may be difficult to drive piles
through some of these layers and pre-drilling of the piles at the parking structure to a
depth of about 35 feet may be required to penetrate the upper sand strata and achieve full
friction capacity.
The pile capacities were estimated using the data available from the CPTs that were
advanccd and the method of estimating pile capacity developed by Esla�ni and Fellenius
(1997). This method uses direct readings of the cone tip resistance to estimate pile
friction capacity by applying correlation coefficients based on soil type. We also
estimated capacities using adhesion factors and shear strength profiles established during
our tield investigation.
�
,ROMIG
E N G I N E E R S
Buriingame Bay
Office Building and Parking Structure
Page 16 of 32
The design lengths for individual 14-inch square PCPS piles and 16-inch diameter auger
cast piles may be estimated using the allowable capacity curves presented on the attached
Figures C-1 and G2, respectively. The allowable pile capacity was calculated based a
factor of safety of about 2.0. The axial capacity rnay be increased by one-third w-hen
evaluating for total loads, including wind or seismic forces. The structural engineer
should confinn that the total structural load on the piles plus the down drag load will not
exceed the structural capacity of the piles.
Please note that soine adjustment of the recommended allowable pile capacities may be
appropriate follo���ing completion of the indicator pile prograin and dynamic pile
monitoring. Depending on the method and details of pile installation, it is possible that
t7eld load testing of auger cast piles will establish higher allowable capacity than shown
on Figure C-2.
We recommend that piles located in a group have a minimum center-to-center spacing of
three times the pile width or diameter. The following reduction factors should be applied
when calculating the group pile capacity during static loading conditions of friction piles.
If a closer spacing is selected, we can provide the appropriate group reduction factor.
Table 5. Reduction Factors for Axial Friction Capacity in Various Pile Groups
Burlingame Bay Office Building and Parking Structure
Burlingame, California
Pile Group Contiguration
2a2 2x3 3x3 3x4 4x4
3 Pile Width
Spacing
Pile Foundation Settlement
1.0 1.0 0.96 0.90 0.85
Based on the allowable pile capacity described above and presented on Figures C-1 and
C-2, we estimate that settleinent of individual piles will be less t11an 3/4-inch to mobilize
the allowable static capacity of the piles. However, post-construction settlement of a
group of piles under signiticant building loads may induce larger settlement under static
conditions. When the column/wall loads and pile configuration are available, we should
be contacted to evaluate settlement of groups of piles under the proposed building loads.
�
�
,ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 17 of 32
Lateral Loads on Piles and Pile Caqs
To estimate the lateral load capacity of individual piles, we used L-Pile, a program that
models lateral pile capacity and load/deflection response. Our lateral pile analyses were
intended to model 40-foot-long 14-inch-square PCPS concrete and 16-inch diameter
auger cast end bearing piles w�ith an axial compression load of 240 kips acting on the
head of the piles during lateral loading. We assumed a pile concrete compressive
strength of about 6,000 pounds per square inch.
Since the length and corresponding capacity of the friction piles have not yet been
selected, an L-Pile analysis for friction piles has not been performed at this time. When
the lengths and capacities are selected, this analysis can be perfonr�ed by us or by the
structural engineer with our input (for geotechnical parameters).
Our analysis used typical average soil conditions and no factor of safety was included.
The structural engineer should use an appropriate factor of safety for their design, as
appropriate. The calculated deflection, bending i�loment, and shear versus pile depth for
various lateral loads under free head and fixed head conditions for the aforementioned
PCPS and auger cast piles are presented on Figures C-3 through C-14 of this report.
Our lateral capacity analyses were based on a single pile condition with pile center-to-
center spacing ranging from 2.5 to 4 times the shaft diameter. For the pile group
spacings, the shear planes in the soil overlap and therefore the resistance for a pile within
the group is less than that of a single pile. To account for the reduction of soil resistance
due to �roup effects, we recommend multiplying the lateral loads corresponding to a
givcn deflection by the factors in Tablc 4 bclow.
For example, a 4 x 5 pile group with a center-to-center pile spacing (S/D) of 3 tiines tl�e
shaft diameter would use p-multipliers of 0.54 and 0.52 for loads applied in the direction
of (perpendicular to) the 4 and 5 pile rows, respectively.
Table 6. Average P-Multipliers for Various Pile Groups
Burlingame Bav Office Building and Parking Structure
Burlingame, California
PILE SPACING (S/D)
2._5 3 4
0 2 0.61 0.68 0.79
� 3 3 0.50 0.59 0.72
0
o�= 4 0.45 0.54 0.69
Z
5 0.42 0.52 0.67
* Nuinber of pile rows in the direction ot�loading
�
,ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 18 of 32
Lateral loads may also be resisted by passive soil pressure acting against the sides of pile
caps and grade beams cast neat in excavations. We recommend that ultimate passive soil
resistance simulated by an equivalent tluid pressure of 450 pounds per cubic foot be used
for design of the upper 6.5 feet of subsurface soil, and by an equivalent fluid pressure of
250 pounds per cubic foot for designed below a depth of 6.5 feet. The passive soil
resistance may begin at the ground surface for grade beams and pile caps, where
appropriate. The passive soil resistance acting on the grade beam or pile cap should be
limited to a unifor�n lateral pressure of 2,500 pounds per square foot. This passive
pressure assumes lateral detlection at the top of the pile cap or �rade beam on the order of
'/�-inch. As discussed above, the structural engineer should use an appropriate factor of
safety for their design, as appropriate.
Indicator Pro¢ram for Driven Pre-Cast Concrete Piles
Some of the uncertainties associated with production pile driving can be reduced by
perforn�ing an indicator pile program. An indicator pile program will provide a means of
helping to establish the ]imits of end bearing strata across the structures and help establish
where high driving resistance may be encountered. The indicator progran� w�ill also more
accurately estimate final pile length and capacity and how lenaths and the need for pre-
drilling vary across the site. �
Due to the variability of expected tip elevations, we recommend about eight to twelve
indicator piles be driven or installed w�ithin each structure footprint before the final pile
casting lengths have been selected; the final number of indicator piles should be
detennined once the pile type is detennined. Some of the indicator piles should be
located close to selected CPT locations. The indicator piles should be driven/installed
with the same equipment that will be used to drive the production piles and can be
installed al production pile locations.
The indicator pile lengths should be based on the design lengths required to meet the
desired end bearin� capacity plus 5 feet at the office building and to the design friction
capacity length at the parking structure. It is likely that some indicator piles may not be
driven to their entire length and will require cutoffs to provide the desired butt elevation.
Indicator piles can be used for building support and should be accurately located. If
PCPS piles are selected for the pi-oject, at least two spare piles should be available as part
of the indicator pile program. Some of the pile locations should be predrilled w-ith a
larger diameter predrill to a depth of 13 feet, to allow for more accurate capacity
estimates during PDA monitoring or pile load testing.
�ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 19 of 32
PDA Monitorin� for Driven Pre-Cast Concrete Piles
A Pile Driving Analyzer (PDA) should be used during the indicator pile program to
determine approximate pile capacities through dynamic testing. PDA monitoring may
allow a reduction in production pile length resulting in cost savings. PDA monitoring
should be performed durin� indicator pile driving and on piles selected for restrike. Pile
re-striking should be performed no sooner than seven days after initial driving.
Since restrike testing more than one day after installation may alter the contractor's
sequencing, it should be clearly identified on the plans and specifications to avoid
unexpected change-orders for out-of-sequence moves. PDA monitoring would be
beneficial for checking tensile stresses in the piles during driving and for evaluating pile
integrity on any piles suspected of being damagcd during indicator or produclion driving.
WEAP Analvsis for Driven Pre-Cast Concrete Piles
The pile contractor should have a wave equation analysis of piles (WEAP analysis)
performed to confirm compatibility and drivability of the pile driving system w�ith the
recommended piles and anticipated soil conditions at the site. We should review the
results of the WEAP analysis prior to mobilization of pile driving equipment to the site.
Pre-Drillin� for Driven Pre-Cast Concrete Piles
The contractor should expect to predrill through the upper fill soil. In addition, dense
sand layers were identitied at depths of about 20 feet and 35 feet beneath portions of the
parking garage footprint and at a depth of about 30 feet beneath portions of the office
building. On a preliminary basis, relatively deep pre-drilling may be required in the
parking garage due to the dense sand interbeds encountered which may prevent the pilcs
from being driven to the required design depths without da�naging the pile. The areas
and depths where this may occur can likely be better established during the indicator pile
program. Where predrilling is required to penetrate these sand layers, an auger no larger
than 12-inches should be used for a 14-inch square pile.
All indicator and production piles should be driven under the continuous observation of
our staff. The piles should be driven without interruption until miniinum pile depth
criteria is �net or refusal driving conditions occur.
It is possible that at some locations beneath the parking garage, refusal driving conditions
will be encountered in dense to very dense sand strata. lf pile driving refusal conditions
are ��et, our office will need to review the pile driving records to assess the vertical and
lateral capacity of the pile, and to detennine in conjunction with the structural engineer
whether additional piles will need to be installed nearby.
,ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 20 of 32
Load Testin� for Au�er Cast Piles
The actual capacity of the augercast piles will depend on the inethods and details of pile
installation and will need to be contirnled in the field by static and/or dynamic load tests
on auger cast test piles priar to constructing the production piles.
As discussed above, due to the difficulty of identifying/verifying end bearing conditions
of auger cast piles, an expanded load test/exploration program may be required.
Auger Cast Pile Installation
If auger cast piles are used, the method, details and equipment for constructio�� of auger
cast piles will be deternlined by a design-build auger cast pile subcontractor. In our
opinion, the auger cast pile design-build contractor should have at least 5 years of auger
cast pile experience and a proven track record of successful design and installation of
auger cast piles in the Qay Area.
We note that the actual capacities and perfonnance that are achieved by auger cast piles
are highly dependent on the method of installation, contractor's experience, and
equipment used. Therefore, monitoring of the installation of the auger cast piles will be
essential in order to confinn the integrity of the piles. We recommend that only
specialized contractors with proper equipment be considered and that all piles be installed
under the observation of the project geotechnical engineer, to contirm that the pile
foundations are constructed in accordance with the recommendations presented herein.
For quality assurance purposes, we recommend that each piling rig be eyuipped wit11 a
Pile Installation Recorder (PIR), or comparable instrumentation, in order to accurately
monitor the installation of each pile. In addition, we recommend that at least six to ten
dynainic pile load tests be perfonned to confinn pile capacity and perfori��ance during the
indicator pile program, dependent on whether end bearing or friction piles are being used.
SPREAD FOOTINGS
In our opinion, miscellaneous lightly loaded landscape improvements may be supported
c�n conventional spread footings bearing on stiffhnediuin dense onsite till soils provided
the potential for consolidation settlement (may be partially mitigated by timing of new
till placement) and seismic related differential movement is acceptable. Once the type of
structures to be supported on shallow foundations are known, these preliminary
recommendations and estimated settlements should be updated for the specific loading
�ROMIG
ENGINEEFIS
Burlingame Bay Office Building and Parking Structure Page 21 of 32
and type of improvement proposed. In general, footings should have a minimum width
of I S inches and extend at least 20 inches below the bottom of slabs-on-grade and at least
26 inches below exterior tinish grade. Footings may be designed for allowable bearing
pressures of 1,500 pounds per square foot for dead plus live loads, with a one-third
increase allowed for total loads including wind or seismic forces. The weight of the
footings can be neglected for design purposes.
All footings located adjacent to utility lines or other footings should bear below a l:l
plane extended upward from the bottom edge of the utility trench. All continuous
footings should be reinforced with top and bottom steel to provide structural continuity
and to pennit spanning of local irregularities.
The bottom of all footing excavations should be cleaned of� loose material. Our
representative should observe the excavations to confini� that they are founded in suitable
materials and have been properly cleaned priar to placing concrete for�ns and reinforcing
steeL If soft or loose materials are encountered at the foundation bearing depth, our field
representative may reyuire over-e�cavation and/or compaction before the reinforcing
steel is placed or may require a deeper footing embed�nent depth.
Lateral Loads for Shallow Foundations
Lateral loads will be resisted by friction between the bottom of the footings and the
supporting subgrade. An ultimate coefficient of fi-iction of 0.45 may be assumed. In
addition to friction, lateral resistance �nay be provided by passive soil pressure acting
against the sides of foundations cast neat in footing excavations or backfilled with
properly co�r�pacted structural fill. We recommend assuming an ultimate eyuivalent fluid
pressure of 4_50 pounds per cubic foot for passive soil resistance, w�here appropriate. In
our opinion, a factor of safety of 1.5 should be included for design. The upper foot of
passive soil resistance should be neglected where soil adjacent to thc footing is not
covered and protected by a concrete slab ar pavement.
Settlement for Shallow Foundations
Thirty-year post-construction differential �novement due to static loads is expected to be
about 1.5 to 2.25 inches for miscellaneous structures supported on shallow foundations,
provided the foundations are designed and constructed as recommended. We note that
this is in additic�n lo the settlement due to liquefaction and static settlement from
placement of new fill estimated in the previous sections of this report. The total
estimated settlement should be considered during the structural design.
�
,ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 22 of 32
ELEVATOR PIT RETAINING WALLS
Elevatar pit retaining walls should be designed to resist lateral pressures from the
adjacent native soil and backfill. Since ground water may rise up to about 1 foot below
the ground surface, we understand that the elevator pit will be designed for un-drained
conditions. Un-drained retaining walls with level backfill that are not free to deflect or
rotate, such as basement walls, should be designed to resist an equivalent fluid pressure
of 80 pounds per cubic foot plus an additional uniform lateral pressure of 8H pounds per
square foot (where H is the height of the wall in feet).
Where the walls will be subjected to surcharge loads, such as from foundations, vehicular
traffic, or construction loading, the walls should be designed for an additional unifonn
lateral pressure equal to one-half of the surcharge pressure.
Based on the site peak ground acceleration (PGA), on Seed and Whitman (1970); A1 Atik
and Sitar (2010); and Lew et aL (2010); seismic loads on retaining walls that cannot
yield, such as the basement retaining walls, may be subjected to a seismic load as high as
about 17H�. This seismic surcharge line load should be assumed to act at 1/�H above the
base of the �vall (in addition to the un-drained active wall design pressure of 80 pounds
per cubic foot).
Backfill placed behind the walls should be compacted to at least 90 to 92 percent relative
compaction using light compaction equipment. If 1leavy equip�nent is used for
compaction of wall backtill, the walls should be temporarily braced.
Retaining walls for elevator pits generally should be supported on pile foundations as
recommended previously. If site retaining ���alls are planned, we should be contacted for
additional recommendations.
SLABS-ON-GRADE
C:eneral Slab Considerations
To reduce the potential for move�nent of the slab subgrade, at least the upper 6 inches of
soil subgrades should be scarified and compacted at a moisture content above the
laboratory optimum. The native soil subgrade should be kept moist up until the time the
non-expansive iill, crushed rock and vapor barrier, and/or aggregate base is placed.
,ROMIG
ENGINEERS
Burlingame Bay Office Building and Parking Structure Page 23 of 32
Slab subgrades and non-expansive iil] should be prepared and compacted as
recommended in the section of this report titled "Earthwork." Exterior flatwork and
interior slabs-on-grade should be underlain by a layer of non-expansive fll as discussed
below.
The non-expansive fill should consist of aggregate base rock or a clayey soil with a
plasticity index of 15 or less; it may be possible to reuse some of the existing on-site
materials or concrete grindings provided they meet the gradation requirements far base
rock.
Considering the potential for soil inoveinents, we expect that a reinforced slab will
perfonn better than an unreinforced slab. Consideration should also be given to using a
control joint spacing on the order of 2 feet in each direction for each inch of slab
thickness.
Exterior Flatwork
Concrete walkways and exterior flat���ork should be at least 4 inches thick and should be
constructed on at least 6 inches of Class 2 aggregate base. To improve perfonnance,
exterior slabs-on-grade, such as for patios and wide walkways, may be constructed with a
thickened edge to improve edge stiffness and to reduce the potential for water seepage
under the edge of the slabs and into the underlying base and subgrade. In our opinion,
the thickened edges should be at least 8 inches wide and ideally should extend at least 4
inches below the bottom of the underlying aggregate base layer.
Structural Slabs
As discussed above, based on the amount of fill and resulting large static settlements at
the office building, it would be preferable to construct the office building floors as
structural slabs supported on the on the pile foundations.
In areas where dampness of concrete floor slabs would be undesirable, concrete structural
slabs should be underlain by at least 6 inches of free-draining gravel, such as '/z- to 3/4-
inch clean crushed rock with no more than 5 percent passing the ASTM No. 200 sieve.
At the interior areas where tloor dampness is a concern, a water-proofing membrane that
will adhere to the concrete slab when ground settlement occurs (such as preproof or
polygard) could be considered between the crushed rock and slab, rather tlian a
conventional vapor barrier.
�
,ROMIG
ENGINEERS
Burlingame Bay Office Building and Parking Structure Page 24 of 32
At-�rade Interior Slabs
Concrete slab-on-grade floors should be constructed on a layer of non-expansive fill at
least 6 inches thick that is placed and compacted on a properly prepared and compacted
soil subgrade. Due to the potential for static and seismic settlement differential
settlement, we recommend that slab-on-grade floors be at least 5 inches thick, and be
reinforced with sufficient steel reinforcement to span across local irregularities. To
reduce the potential for slab distress, at-grade interior slabs may be designed as structural
slabs spanning across the building foundations.
As discussed above, at the parking structure, it would be advisable to place fill reguired
to raise grades directly beneath and slightly beyond the parking structure footprint and
leave in place for about 4 to 6 months prior to construction of the slabs to allow time for
the consolidation settlement to occur.
In areas where dampness of concrete floor slabs would be undesirable, concrete slabs
should be underlain by at least 6 inches of tree-draining gravel, such as '/�- to 3/4-inch
clean crushed rock with no �nore than 5 percent passing the ASTM No. 200 sieve. Pea
aravel should not be used for this capillary break material. The crushed rock layer should
be densified and leveled with vibratory equipment, and may be considered as the non-
expansive fill reco�nmended above.
To reduce vapor transmission up through at-grade concrete floor slabs, the crushed rock
section should be covered with a high quality, UV-resistant vapor barrier confor���ing to
the requirements of ASTM E 1745 Class A, with a water vapor transmission rate less
than or eyual to 0.01 penns (such as 15-mil thick "Stego Wrap Class A"). The vapor
barrier should be placed directly below the concrete slab. Sand above the vapor barrier is
not recommended. The vapor barrier should be installed in accordance ���ith ASTM E
1643. All seams and penetrations of the vapor barrier should be sealed in accordance
with manufacturer's recommendations.
The below-grade elevator pit should be underlain by a high-quality water-prooting
membrane selected by your water-proofing consultant.
The permeability of concrete is affected significantly by the water:cement ratio of the
concrete mix, with lower water:cement ratios producing more da�np-resistant slabs and
stronger concrete. Where moisture protection is important and/or where the concrete will
be placed directly on the vapor barrier, the v��ater:cement ratio should be 0.45 or less. To
increase the workability of the concrete, mid-ran�e plasticizers can be added to the mix.
Water should not be added to the concrete mix unless the slump is less than specitied and
the water:cement ratio will not exceed 0.45.
�ROMIG
E N G 1 N E E F 5
Burlingame Bay
Office Building and Parking Structure
Page 25 of 32
Other steps that may be taken to reduce moisture transmission through the concrete slabs-
on-grade include moist curing for 5 to 7 days and allowing the slab to dry for a period of
two months or longer prior to placing floor coverings. Also, prior to installation of the
floor covering, it inay be appropriate to test the slab moisture content for adherence to the
manufacturer's requirements and to determine whether a longer drying time is necessary.
VEHICLE PAVEMENT
If sections of asphalt concrete pavement will be replaced, based upon the laboratory test
results and our field investigation, an R-value of 10 appears to be appropriate for design
of the parking areas and traffic driveways. Using estimated traffic indices for various
pavement loading conditions, we developed the minimum pavement section thicknesses
presented in Table 7 based on the procedure included in Chapter 630 of the Caltrans
Highw�ay Design Manual.
Table 7. Minimum Asphalt Concrete Pavement Section Thicknesses
Burlingame Bay Office Building and Parking Structure
Burlingame, California
General Traffic AC Thickness Aggregate Base* Total Section
Traffic Condition Index (inches) (inches) (inches)
Automobile Parking
Autoil�obile Access
Light Truck Access
Moderate Truck Access
Heavy Truck Access
4.0 2.5
4.5 3.0
5.0 3.0
6.0 3.5
6.5 3.5
*Caltrans Class ? Aggregate I3ase (minimum R-value = 78).
7.0
8.0
9.0
12.0
14.0
9.5
11.0
12.0
15.5
17.5
The Traffic [ndices used in our pavement thickness calculations are considered
reasonable values for this development and are based on engineering judgment rather
than on detailed traffic projections. Asphalt concrete and aggregate base should conform
to and be placed in accordance with the requirements of the Caltrans Standard
Specifications, latest edition, except that coinpaction should be based on ASTM Test
D1557.
�
,ROMIG
E N G I N E E R S
Burlingame Bay Office Buiiding and Parking Structure Page 26 of 32
We recommend that �neasures be taken to limit the amount of surface water that seeps
into the aggregate base and subgrade below vehicle pavements, particularly where the
pavements are adjacent to landscape areas. Seepage of water into the pavement base
material tends to soften the subgrade, increasing the amount of pavement maintenance
that is required and shortening the pavement service life. Deepened curbs extending
4-inches below the bottom of the aggregate base layer are generally effective in limiting
excessive water seepage. Other types of water cutoff devices or edge drains may also be
considered to maintain pavement service life.
Ri�id Concrete Pavements
The minimum thickness of the concrete pavements at the site should be based on the
anticipated traffic loading, the modtiltis of rupture of the concrete used for pavement
construction, and the composition and supporting characteristics of the subgrade below
the pavement section. If rigid conerete pavement is planned for the proposed parking lot
and driveway, the pavement section may be designed and constructed in accordance with
American Concrete Institute (ACI) 330R-08 - Guide for Design and Construction of
Concrete Parking Lots.
Based on the near-surface clayey soils we encountered at the project site, a]ow subgrade-
subbase support strength value of 100 pci was assumed in our analysis. ln addition, our
design assumes that pavements will be restrained laterally by a concrete shoulder or curb,
and the concrete will have a compressive strength, f'c, of at least 3,500 psi and a t7exural
strength, MR, of at least 500 psi. Reinforcing steel may be used for shrinkage crack
control. In addition, maximum spacing should be provided between contraction joints in
both directions. Our recommendations for minimu�l� rigid pavement sections and
maximum spacing between joints are presented in Table 8 below.
Traffic
Categories
Car Parking and
Access Lanes
Truck Parking
and Access
Lanes
Table 8. Rigid Concrete Pavement Design
Burlingame Bay Office Building and Parking Structure
Burlingame, California
Maximum Concrete Aggregate Total Maximum Spacing
ADTT* Thickness Base Section between Joints
(inches) (inches) (inches) (feet)
1 5.0 6.0
25 6.0 8.0
300 7.0 8.0
13.0 12
14.0 15
15.0 15
*AUTT = A��erage daily truck traffic in both directions (excludes pancl trucks, pickup t��ucks,
and other four-w�heel vehicles)
�ROMIG
ENGINEEFiS
Burlingame Bay Office Building and Parking Structure Page 27 of 32
EARTHWORK
Clearing and Subgrade Prenaration
All deleterious materials, such as existing foundations, slabs, pavements, till soils,
designated utilities, vegetation, topsoil, and root systems, should be cleared from areas to
be built on or paved. The actual stripping depth should be established by us at the time of
construction. Excavations that extend below finish grade should be backfilled with
structural till that is water-conditioned, placed, and compacted as recommended in the
section titled "Compaction."
After the site has been properly cleared, stripped, and excavated to the required grades,
exposed soil surfaces in areas to receive structural fill or slabs-on-grade should be
scaritied to a depth of 6 inches, moisture conditioned, and compacted as recommended
for structural iill in the section titled "Compaction."
Re-use of Existing Concrete and A�gre�ate Base and Subbase
After stripping of the existing pavement, the removed concrete, aggregate base and
subbase materials may be re-used as structural fill or non-expansive fill, provided that the
concrete will be grindcd and mixed with the on-site aggregate base and subbase
materials. In addition, the mixture should be well-graded with sufficient binder, have a
plasticity index of 15 or less, and have a maxi�num particle size and meeting the
structural till requirements as described in the Material for Fill section below. Placement
of asphalt grindings should be avoided below the structures.
Flexible Connections for Undereround Utilities
As discussed above, varying amounts of settlement is expected across the site due to the
loads from the new fill and presence of the compressible f3ay Mud. The above estimated
settleinent should be considered during the design of the underground utilities to be
constructed within or around the building pads or across portions of the site requiring
varying amounts of new till. In addition, underground utilities should be designed to
tolerate the estimated differentia] settlements by including flexible connections, and
gravity-flow pipes may be require a steeper gradient to ensure the intended positive flow
over the design life of the project.
Bav Mud Considerations
Open excavations and trenches in Bay Mud are prone to instability such as collapse due
to the lack of strength. Therefore, excavations within or extending near the soft saturated
,ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 28 of 32
Bay Mud material will require special methods or care such as shoring, bracing or
sloping the cut slope to an appropriate inclination during construction to avoid collapse
and/or failure.
Heavy equipment and/or stockpiles at the site can cause settlement of Bay Mud and could
potentially cause instability of nearby open excavations and should generally be avoided.
Utility Trench Backfill
Utility trench excavations should follow in accordance with all applicable local, state and
federal safety regulations, including the current OSHA excavation and trench safety
standards. Excavation extending into the soft �ay Mud will require shorin�. All trench
backfill material should be moisture conditioned and compacted as recommended in the
section of this report titled "Compaction." Utility penetrations through walls or footings
should be properly sealed. Proper compaction of utility trenches below pavement areas is
essential to prevent future settlement and the resulting damage and maintenance costs of
the pavement.
Utilities with sand bedding can become conduits to bring subsurface water below
building and pavements particularly when located adjacent to well irrigated landscaping
areas. Where utility trenches interface with the building pad or pavement areas, an
i�npenneable plug should be installed to limit the potential for subsurface w�ater to tlow
along the utility trench and saturate subgrade soils. In our opinion, the impenneable plug
could consist of compacted clayey on-site soil, lean concrete slurry, or other approved
i�npenneable material.
Temporary Dewatering For Excavations
As discussed above, ground water may rise up to about 1 foot below existing grades.
Therefore, construction dewatering may be required depending on the depth of tempor�ry
excavations, such as for utility trenches and/or elevator shafts, and the ground water level
at the time of excavation.
Temporary dewatering for construction should be the responsibility of the contractor.
The selection of equipment and methods of dewatering should be left up to the contractor
and, due to the variable nature of the subsurface conditions, they should be aware that
modifications to the dewatering system may be required during construction dependi�Ig
on the conditions encountered. Additionally, the ground water should be maintained at
least 2 feet below all local excavations for deepened foundations, utilities or other
structures. The contractor should design a system to achieve these criteria.
,ROMIG
E N G 1 N E E R S
�' Burlingame Bay Office Building and Parking Structure Page 29 of 32
Special considerations may be required prior to discharge of ground water from
dewatering activities depending on the quality of the ground water, and environmental
iinpacts at the site or at nearby locations. T`hese reyuii-ements may include storage,
testing and/or treatment under permit prior to discharge.
Temporary Slopes and Excavations
The contractor should be responsible for the design and construction of all temporary
slopes and any required shoring. Shoring and bracing should be provided in accordance
with all applicable local, state, and federal safety regulations, including current OSHA
excavation and trench safety standards.
Excavations that extend below ground water will require tlatter inclinations or ten�porary
shoring. If deep excavations are required, we can provide further input as needed.
If deep excavations are required to extend into or close to the soft saturated Bay Mud,
�_ they may be prone to sloughing and/or caving if excavated near-vertical, and could
�
become unstable. If excavations will extend into the Bay Mud, sheet piles or an
equivalent shoring method will likely be required to support the walls of the excavations.
This information should be considered by the contractor when establishing temporary
shoring/bracing/cut slope criteria for any deep utility trench excavations and other
temporary cuts.
Because of the potential far variation of the on-site soils, field modification of temporary
cut slopes may be required. Unstable materials encountered on slopes during and after
excavation should be trimmed off even if this requires cutting the slopes back to a flatter
inclination.
Protection of structures near cuts should also be the responsibility of the contractor. In
our experience, a preconstruction survey is generally performed to document existing
eonditions prior to construction, with intermittent monitoring of the structures during
construction.
We noted that portions of the sands and silts encountered at the site were judged to have
limited cohesion and will be prone to sloughing and/or caving if excavated near-vertical.
This information should be considered by the contractor when establishing temporary
shoring/sloping criteria for deep excavations, such as utility trenches.
�
,ROMIG
E N G 1 N E E R S
Burlingame Bay Office Building and Parking Structure Page 30 of 32
Material For Fill
All on-site soil containing less than 3 percent organic material by weight (ASTM D2974)
should be suitable for use as structural fill. Structural fill should not contain rocks or
pieces larger than 6 inches in greatest dimension and no more than 15 percent larger than
2.5 inches. lmported non-expansive till should have a Plasticity Inde� no greater than I 5,
should be predominately granular, and should have sufficient binder so as not to slough
or cave into foundation excavations and utility trenches. Recycled aggregate base should
not be used for non-expansive iill at building interior. A member of our staff should
approve proposed import materials prior to their delivery to the site.
Compaction
Scariiied soil surfaces and all structural fill should be placed and compacted in unifornl
litts no thicker than 8-inches in uncompacted thickness, conditioned to the appropriate
moisture content, and compacted as recommended for structural fill in Table 9. The
relative compaction and moisture content recommended in Table 9 is relative to ASTM
Test D 1557, latest edition.
Table 9. Compaction Recommendations
Burlingame Bay Office Building and Parking Structurc
Burlingame, California
General
Relative Comqaction*
90 percent
90 percent
90 percent
92 percent
95 percent
95 percent
Moisture Content*
Above optimum
• Scarified native subgrade in
areas to receive structural fill.
• Structural till composed
of native soil.
• Structural till composed
of non-expansive fill.
• Fill deeper than 5 feet.
Pavement Sub�rade
• On-site soil.
• Aggregate base.
Above opti�num
Above optimum
Above optimum
Above optimum
Near optimum
Utilitv Trench Backfill
• On-site soil. 90 percent Above optimun�
• Imported sand. 93 percent Near optimum
* Relative to ASTM Test D1557, latest edition.
�ROMIG
E N G 1 N E E R S
�' Burlingame Bay Office Building and Parking Structure Page 31 of 32
At the start of site grading and earthwork construction, and prior to subgrade preparation
and placement of non-expansive fill, representative samples of on-site soil and import
material will need to be collected in order for a]aboratory compaction test to be
performed for use during on-site density testing. Sampling of on-site soil and proposed
import material should be requested by the contractor at least 5 days prior to when our
staff will be needed for density testing to allow time for soil sampling and laboratory
testing to be perfonned prior to our on-site compaction testing.
Permanent Slopes
Pennanent slopes should be cut or tilled preferably to an inclination of 2.5:1 (horizontal
to vertical). Exposed slopes may be subject to minor sloughing and erosion, which may
require periodic inaintenance. We recommend that the slopes be planted to minimize
erosion.
Surface Draina�e
Finished grades should be designed to prevent ponding and to drain surface water away
from foundations and edges slabs and pavements, and toward suitable collection and
discharge facilities. Slopes of at least 2 percent are recommended for flatwork and
pavement areas with 5 percent preferred in landscape areas within 8 feet of the structures,
where possible. At a minimum, splash blocks should be provided at the ends of
downspouts to carry surface water away froin peri�neter foundations. Preferably,
downspout drainage should be collected in a closed pipe syste�n that is routed to a stonn
drain system or other suitable discharge outlet.
Drainage facilities should be observed to verify that they are adequate and that no
adjustments need to be made, especially during first two years following construction.
We recommend that an as-built plan be prepared to show the locations of all surface and
subsurface drain lines and clean-outs. Drainage facilities should be periodically checked
to verify that they are continuing to f'unction properly. The drainage facilities will
probably need to be periodically cleaned of silt and debris that may build up in the lines.
FUTURE SERVICES
Plan Review
Roinig Engineers should review the completed grading and foundation plans for
conformance with the recommendations presented in this report. We should be provided
with these plans as soon as possible upon their completion in order to limit the potential
for delays in the permitting process that might otherwise be attributed to our review. In
'ROMIG
E N G I N E E R S
Burlingame Bay Office Building and Parking Structure Page 32 of 32
addition, it should be noted that inany of the local building and planning departments
now require "clean" geotechnical plan review letters prior to acceptance of plans for their
tinal review. Since our plan reviews typically result in recommendations for
modification of the plans, our generation of a"clean" review letter often requires two
iterations.
At a minimum, we recommend the 1�ollowing note be added to the plans:
"Earthwork, slab subgrade and non-expansive fill preparation, foundation construction,
pile driving/installation, pile load testing, utility trench backfill, pavement construction,
and site drainage should be performed in accordance with the geotechnical report
prepared by Romig Engineers, Inc., dated April 21, 2020. Romig Engineers should be
notified at least 48 hours in advance of any earthwork and foundation construction and
should obsei-ve and test during earthwork and foundation construction as recommended
in the geotechnical report. Romig Engineers should be notified at least 5 days prior to
earthwork, trench backtill and subgrade preparation work to allow time for sampling of
on-site soil and laboratory compaction curve testing to be perfonned prior to on-site
compaction density testing."
Construction Observation and Testin�
The earth��ork and foundation phases of construction should be observed and tested by us
to 1) confirm that subsurface conditions are compatible with those used i�i the analysis
and design; 2) observe compliance v��ith the design concepts, specifications, and
recommendations; and 3) allow design changes in the event that subsurface conditions
diffcr from thosc anticipatcd. Thc rccommcndations prescntcd in this rcport arc bascd on
a limited amount of subsurface exploration. The nature and extent of variation across the
site may not become evident until construction. If variations are exposed during
construction, it will be necessary to reevaluate our recoil�mendations.
.•. .'. .•. .•. .•.
�ROMIG
E N G I N E E R S
REFERENCES
Aagaard, B.T., Blair, J.L., Boatwright, J., Garcia, S.H., Harris, R.A., Michael, A.J.,
Schwartz, D.P., and DiLeo, J.S., 2016, Earthquake outlook for the San Francisco Bay region
2014-2043 (ver. 1.1, August 2016�: U.S. Geological Survey Fact Sheet 2016-3020, 6 p.,
http://dx.doi.org/ 10.3 l 33/fs20163020.
Al Atik, L., and Sitar, N., 2010, Seismic Earth Pressures on Cantilever Retainin� Structures,
Journal of Geotechnical and Geoenviron�nental Engineering, ASCE Vol. 136, No. 10.
American Concrete Institute (ACI), 2008, Guide for Desi�n and Construction of Concrete
Parkin� Lots: ACI 330R-08.
American Society of Civil Engineers, 2016, Minimum Desi�n Loads for Buildin�
Other Structures, ASCE Standard 7-16.
California Building Standards Commission, and International Code Council, 2019
California Buildin� Code, California Code of Re�ulations, Title 24, Part 2.
California Department of Transportation (Caltrans), 2012, Hi�y Desi�n Mailual:
Chapter 630 for Flexible Pavement Design.
California Gcological Su��ey, 2018, Seismic Hazard Zone Report far the San Mateo 7.5-
Minute Quadran�le, San Mateo County, California, Seismic Hazard Zone Report 113.
California Geological Survey, 2019, Seismic Hazard Zones Map of the San Mateo
Quadran�le.
Lew�, M., A1 Atik, L., Sitar, N., Pourzanjani, M., & Hudson, M., 2010, Seismic Earth
Pressures on Deep F3uilding Basements, SEAOC 2010 Convention Proceedings.
Pampeyan, Earl H., 1994, Geolo�ic Map of the Montara Mountain and San Mateo 7-1/2'
Quadran�les, San Mateo, Count� California, U.S. Geological Survey Map I-2390.
U.S.G.S. - McDonald, S., Nichols, D., Wright, N., & Atwater, B., Ma� Showin�
Thickness of Youn e� r Bay Mud, Southern San Francisco Bay, California, Map MF-976,
1978.
U.S.G.S., 2019, U.S. Seismic Desi_�ps, Earthquake Hazards Program,
http://earthquake. usgs. gov/designmaps/us/application. php
.•. .•. .•. .•. .•.
. . . .
,ROMIG
E N G 1 N E E R S
VICINITY MAP FIGURE 1
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA PROJECT NO. 5047-1
,ROMIG
E N G 1 N E E R S
Scale: 1 inch = ?000 feet
Base is United States Geological Surv°ey San Mateo 7.5 Minute Quadrangle, dated 1997.
�
\�
l
7 "
� .�
�E� 5��
8-srory/ 139K
•
� —
- ;. --�-
Burlingame Lagoon
_ "` t
. — --�.
a., -� - - P _
�0� � t
P�� _ i.
E[i-2 ._... _. �
R� �'�., CPT-4 '
�- ,
' , I �,
�
•s - � �
CPT-5 ; •� - I i r
7� . 1 I N
� � , • ' 1 d
Ne%arkingQe gA ' � �
, � � B+S►4 � I �
,�CPT-1 � • , v�°a CPT-3' �
�
, ao L 9' � I,
. ,. �
� i� �s� EB-1 � �
� � �
�����`�' CPT-2 � *
(E) 555 *" � i
PJew Office Building 5-story� 120
8-story.240K � �
� CPT-6 � ~` ,
CPT-7---- ____ �� a1„ �
-. _� . - .. t y �
—��..�_'_—
----
LEGEND
EB-2 �j- Approximate Locations of Exploratory Borings.
CPT-7 � Approximate Locations of Cone Penetration Tests.
Approximate Scale: 1 inch = 200 feet.
E3ase is site plan prepared by DES Architects + Engineers, dated July 9, 2019.
1
�;
,�
�,\
i �';
14
0 100 200 400feet
SITE PLAN
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
,ROMIG
E N G I N E E R S
FICURE 2
APRIL 2020
PROJECT NO. 5047-1
�8 z . ��,.�...,�4 � � ;
r3 �i+�� �'� � y�. t � ,
•� i� , � -s. r•:+f�4 .
� . -'�i f ` .��► . � ' y� ' - .« - - � �y -i .
='1 .,��� ��.k _�ji�f� ���� � �' ' . � �
nL`� . . f'. 7✓�jiy r •,�' � `T• . Q� - '�r' ."i I.'
j� 1�j,�,j'^� ��. � 4 e . � � . ' . .
i," �..'� .:�4;. . � �+�, �. �
'!�,/ ,' •i'%.r,�,,�>> �* �r �,° •�':� 't;�- M1_ Qm , ..... _.
fr: , '.. `.j � ` � �,, � +r.' :�„• ,,4 . . • , ,� _ _�'
/ , ��; � ... ` .�� �I� �•'`•`�� � - .. .. __ '�; ' �
��� � - .� oa�- ����� ' . � SITE ��;-�`��
Q� � � ,�i - 1s�►���� . Qe�, : � .; ,
, � f� � f '�'.
� �;.;� .1 e • `... � ,�.i� � ,,..� �rv� . . .
.'• �':. _._.,:�.Oc7 ; �c�� ;" ., ' '., � . .
�, � '^.
W�/ �
T�nr
� � t y \� kSMS���Y ' • J � ��_ � .
f� ` .' '` r `-�
.�
r�. /.�.� ,�.. .
1�"�.�.i Q n 2 1 C� A
' J`,���
/
`:,�: :t
<,�; . `t=---.
i-;:� -
�
-4i2 �7
.,.. p.`C ' T,,,� :.��.T�.,,,,,r,�.,_�,��'' ^!'f-'R �� �-..
� �"� ' � / � � i � � � f/�%i/.i� �%//� ��i�Y ,'""'r..����,.�7"i% '�'I � ��
�/ / �, ��,i �� � i�!,.� / : �l �,. � �.�� il. .. , � 7
:6 ' '� /�/,//. `'' '� � r %/' f ' � � � -` '_� ' �',
l" �� �� ` '
i� '���%'� �;�. ,� . ..';�f;;;�%�`' ' ... �:% �.
;'� ,i � li� . .��,, �C1pa �/�i.' % . ,
� �'��'� +�� r' � � �%�i�f ' Q�9 � ,'
,r . � � r .� � t'� . .�: -�. .
� -%� ..� .�/ �j i• ��� .
�,..�,,:h!:% , �, ,J, , � !���. -,r%,
� " �l" � i. � �,s , -
`%c._' - �. s �, �.
i �,,;; '•'. , , • ;� s.
f� _,� `1 Qsri �. � r`. �� :% %� ! I, fc �I
LEGEND
, Q'�'8 Sedimentary deposits, undivided ____ _ __ Geologic Contact - dashed w�here
approaimate, dotted ���here inferred.
Qa.rr1 Medium-grained alluvium
Qac . Coarse-grained allu� ium _��_�___ Fault - dashed ���here approximate,
----------------'j - dotted where inferred.
Qsr Slope wash, ravine fill, and colluvium
df + Artiticial fill - Unit 1
�ur� O(dcr alluvium 0 1000 2000 4000 feet
Scale: 1 inch = 2000 feet
Base is Geologic 'Vlap of the Montara Mountain and San Mateo 7.i Minute Quadrangles, San Matco County,
California, (Pampeyan, 199�).
VICINITY GEOLOGIC MAP
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFnRNIA
FIGURE 3
APRIL 2020
PROJECT NO. 5047-1
,ROMIG
ENGINEERS
�,- . � ��f� 1"��- r- ; :� ���:�,;.1� � �.:�'. �� . � ::: � ; : . ..-:: �_- 1
► -�.=�' ��'�-��� �� � �� :�.�:. _�_��; t ':�� ;
- � � . _ ..._. _ , ��►�'
r. �.� _ ..: , ... .:- .: � ..- ,••. y - •- .
� ��.��" " !; . :i . ::: � � •- . , , _ _ �- �,
° 1�"v� 't ' ' ��'- - _ -�� . . _ _ • , . � t-�
r�. �<`�; •►-•-� t -� �T' �' '•_ _.- - _2.� : ,�� . .' : . � �;`i'
��, � , ..• ,.. , . ,_ __ ••
� . ��y, t � . � % � . " _ � . � . . i : � � T
� ��� _. �� �� , • ••.' ., ?:. .�_�.•.� . ' •� �' - --• :', ' =` •�••
•,� �� � , " � ��, � • i' '• . • ` IY
' � ` � A � _ � . . • .► 'ZM _ y • 1 . ♦• ••' .'�
,••�.'.•1� `�` ,_F/ '��,. '� ' .�� � '' ••t . �.�' _�.� � ..� •, .�
.::;u_.- �;,�� ,1��` ,:. :.' � �- �� ; • , •. . .�••_ _' 'i �
~��= y ♦i��. ��'�N ' � �Z•�i �• • • •�� N� " . "���. r, • . . .
�I �•�� ���'�� ') ��'�' �• • -- . •��/ « . �1�, , �, .. .. . ��.• '
.r.;,,,_-..t.�. ':- - • - _= s ,�c�; ' . _ : . . . ,_.' ,_�!'! � � . _ ;�i..
': - - • I''. :,- • r'�:..: _ , '' • ' .' ' - � �i,,�i+ ; : 11: ��„ - .. � � ` � • . ..
Y `'r �''r•-T�S r' �.'•✓'.��•� -- '•- • • ' . . �- - .w..���` � � � :�:'� � _.
�. ; . � ..- f • ; f , , � �."`.'_ . �; � 1�:�
�.i.�: =-�• �. _- i::= ..;�:...: .r-�•;� , �'_ '_' . .' �, - _' �1. . .
�'i,�__ ��;�... .�7� . '-, ~• ;��til� .. '_.t� �•• _ �i,. - , : .. ..� . , � � s'
�1•�1•:�� � • ' �I'��• --"��wr �r.�ivi... "�. ..���• �.. � =, ,� ,-.�: . :.. ;� ..
�t�;i,'�h'�� "�. -- '., •, : . �� .. ��{'�.'" �. a,�,,.�:�,,,��.. -•:- . ��� , �
' �:•;- 1�•. .•, ,'',.. t- • .: . •• '= ��� �? -'_.
�• • , . - -• : i ,�... �-r� • .. . . ..:s-:- t -.�•_
� .t ��. •-.�i�.!'�'�r- : G-- . :.� �-r. . : "'. . . ..� -1
. _ _ � , . � i-. •'.: � {. . . -.[.. • . . _ _ . • �
- , •..: i,., Y - , � , �- _.• _ .,. ,� �'t�w. ►� _' : . _I .. .,
/ / � ,�_.,��� .�• ,�r .: .. •• A' � �. rF ...��.1.'s� .� :� r♦ .' .
� �� � t�1 ►1 .. ��y ��� . " .. � - ' :�. • t , _.� . -.. �� �~� i ���
. 't . � � . . . . � . .. : .. � - � �-�i � . • , • . "�
, % -i47'�►��, •L2��:• .� �,�' ,: ..i , i �.._��' .
'� -•�.t •. • � � , � - -s • "+�+�4.
,1'`... ' �.- ..�. ��• •�~ '•�• •��' -ly= -' ,�'�
•��.;y:/ � '_-.!' , _ '�..( �
��. ,�
� �- � _-�_ ` �-�...� ��': :_i: I�'- / i
. �".r
� r
� • /
r � •'I /
v • ��
Scale: 1 inch = ?000 feet
SITE ���
��`
� , .
0 1000 2000 4000feet
I3ase is U.S. Geological Sur��ey, Map Sho��in� Thickness of Young Bay Mud, Southern San Francisco I3ay,
California (McDonald, Nichols, Wright, and Atwater, 1978)
CONTOUR MAP OF YOUNG BAY MUD THICKNESS
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
FIGURE 4
APRIL 2020
PROJECT NO. 5047-1
'ROMIG
E N G 1 N E E R S
r I
_I O � 1
�`�.� _-- ." . � . �
� �._'i�; --- ,. � �S �'I.1�111 ��
• p '-���: , v
a _ _ _ •� • • � �';..
� 4 �'-'�dh .,�� . H �.: ti�: �rd �� � ,c��
Fi.�n�_�_�_�, �, • :p w (�I��.�.ant
i �
(-' .1�:111,� `\ �' �y � : dA • �
�: - � � �+ ^ �
O -
• 'yd `-O �`' °',r
. �+1 �-- - .�
_ �I��.n: � . .� "P-- �°�i�0,� dG�
� � � � � �
� o _ ._ d �
`� 111 . A
� I•.l�tt��� 'Fra�t�i� � C3.�
SITE � . � , d
. � . °
., • •
F I � •r.�n��:I.i � R�`A�,� �!I � �
'_ Ity l O
H.ilf 1.1� ��,n f�.r, 9�y � j Z `. �
� , lod .�._ -- — �, � i
d� _ �. �'� • _ � F�,u_. i�:ui��►.,:
� - . �� --:>�. �i�. �' :, o
� � 1 � - �
O � _ ; � � � ` . � ; t, +�� `r, - :;.
d ' r� � �. � .'� � .l Il t .l , f'
G� ! � � . �, Sunn � �: �Ie � :I �r �
, , O � � ,f - Y � C�tl ��OSt
.. `\ � � �_ �.h���
p O � (a. =�
� �,. T A C R G' I A,* r; t_� �,,�; �Q; O`v �� �m��bell �
. ���}�'r . � .
i •
� � ir itO� i N.:
O
- . ,►• � � -� �
. f�•��: i � . � ,.-�t�
�1 ' O y�ih
t3�
'Q 8 B'� �`J ", 0 3 6 12 miles
• F'�1•�� �1
.� "- -t . ( ��
Magnitude Year
° -' � '_' ' J �� � C� • � �_� •
,. -- a�,_,_._,�,� =��_��- _���� _�����--.-,-,----_-.-,.`,--�.-�_--,.-
�. �.5+ !. _�+ P:14+ 1.1=�� , _ i- ___ . _ _ _ . _ _ _ _ ____ ", __ _ __ _
Earthquakes w�ith M�+ from 1900 to 1980, M2.5+ from 1980 to January 2015. Faults with activity in last 15,000 years.
Based on data sources from North�rn California F,arthquake Data Center and USGS Quaternary Fault and Fold
Database, accessed May 2015.
REGIONAL FAULT AND SEISMICITY MAP
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
FIGURE _5
APRIL 2020
PROJECT NO. 5047-1
,ROMIG
E N G I N E E R S
APPENDIX A
FIELD INVESTIGATION
The soils encountered during drilling were logged by our representative and samples
were obtained at depths appropriate to the investigation. The samples were taken to our
laboratory where they were examined and classified in accordance with the Unitied Soil
Classification System. The logs of our borings and a summary of the soil classification
systems that were used (Figure A-1) is attached.
Several tests were perfonned in the field during drilling. The standard penetration test
resistance was deternlined by dropping a 140-pound hainmer through a 30-inch free-fall
and recording the blows required to drive the 2-inch (outside diameter) sampler 18
inches. The standard penetration test (SPT) resistance is the number of blows required to
drive the sampler the last 12 inches and is recorded on the boring log at the appropriate
depths. Soil samples were also collected using 3.0-inch O.D. drive samplers. The blow
counts shown on the logs for these larger samplers do not represent SPT values and have
not been corrected in any way.
The Cone Penetration Tests (CPT) were carried out by Middle Earth Geo Testing, Inc.
using an integrated electronic cone system. The CPT soundings were performed in
accordance with ASTM standards (D 5778-95). A 20 ton capacity cone was used for all
of the soundings. The cone had a tip area of 10 cm-' and friction sleeve area of 150 cm'-.
The logs of our CPTs are attached in this Appendix.
The locations of the borings and CPTs were established by pacing using the site plan
provided to us. The locations of the borings/CPTs should be considered accurate only to
the degree implied by the method used.
The boring and CPT logs and related infonnation depict our interpretation of subsurface
conditions only at the specific location and time indicated. Subsurface conditions and
ground water levels at other locations may differ from conditions at the location where
sampling and testing were conducted. The passage of time may also result in changes in
the subsurface conditions.
.•. .'. .•. .•. .•.
. . . .
�
,ROMIG
ENGINEEFiS
USCS SOIL CLASSIFICATION
�
PRINIARY DIVISIONS SOIL SECONDARY DIVISIONS
TYPE
CLF.AN GRAVEL GW p� Well graded gravel, gravel-sand mixtures, little or no fines.
COARSE GRAVEL �� 5°'� F�nes> Gp p� Poorly graded gravel or gravel-sand mixtures, little or no fines.
GRAINF,D GRAVE.;� with GM � Silty gravels, gravel-sand-silt mixtures, non-plastic tines.
SOILS FiN�-:s GC Clayey gravels, gravel-sand-clay mixtures, plastic fines.
<<�. so °o F[nes� c1.EAt� SAN[� SW :o.e Well graded sands, gravelly sands, little or no fines.
SAND �` '��° F""�� SP : Poorly graded sands or gravelly sands, little or no tines.
sn'vU SM a��e� Silty sands, sand-silt mixtures, non-plastic fines.
w'�TH F'i�vf'S SC Clayey sands, sand-clay mixtures, plastic tines.
....�
ML �•��� Inor�anic silts and very fine sands, with slight plasticity.
p�F SILT AND CLAY CL Inorganic clays of low to medium plasticity, lean clays.
GRAINED 1�iyuid Iimit ��o°o OL ;�;�; Organic silts and organic clays of low plasticity.
SOILS MH Inorganic silt, micaceous or diatonlaceous fine sandy or silty soil.
�> �o °-�o F�r,es) SILT AND CLAY CH Inorganic clays of high plasticity, fat clays.
Liquid limit -> �o°� OH Organic clays of inedium to high plasticity, organic silts.
HIGHLY ORGANIC SOILS Pt Peat and other highly organic soils.
BEDROCK BR Weathered bedrock.
RELATIVE DENSITY CONSISTENCY
SAtiD & GRAVEL
VERY LOOSi:
LOOSE
MEDIUM DENSE
DENSI?
VERY DENSI;
BLOWS/FOOT*
Oto4
4 to 10
lOto30
�0 to 50
OVF,R 50
SILT & CLAY STRENGTH^ BLOVVS/FOOT*
VERY SOFT 0 to 0.?� 0 to ?
SOFT 0?5 to 0.5 2 to 4
FIRM 0.5 to 1 4 to 8
STIFF 1 to 2 8 to 16
VERY STIFF 2 to 4 16 to 32
HARD OVER 4 OVI:R 32
cuAiN sizEs
BOULDF,KS COBBLES GRAVEL SAND SILT & CLAY
COARSE FINE? COARSFi MEDIUM FINF
��,� i�� Q75" 4 10 40 200
SIEVE OPENINGS U.S. STANDARD SERIF,S SIEVF.
Classification is based on the Unified Soil Classificatioi� Systen�; tines refer to soil passing a No. 200 sieve.
* Standard Penetration Test (SPT) resistance, using a 140 pound hammer falling 30 inches on a 2 inch O.D. split spoon
sampler; blow counts not corrected for larger diameter samplers.
^ Uncontined Compressive strengtl� in tons/sq. ft. as estinlated by SPT resistance, tield and laboratory tests, and/or
� isual observatio�i.
KEY TO SAMPLERS
1 Modified California Sampler (3-inch O.D.)
I Mid-size Sampler (2.5-inch O.D.)
I Standard Penetration Test Sampler (2-inch O.D.)
KEY TO EXPLORATORY BORING LOGS
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
FI(TURE A-1
APRIL 2020
PROJECT NO. 5047-1
,ROMIG
ENGINEERS
DRILL TYPE: Mobile Urill F3-40 with 8" Hollo��� Stem Auger LOGGED BY: EHD
DEPTH TO GROUND WATER: 20' SURFACE ELEVATION: 5' DATE DRILLED: 2/13/20
��
� ;� � x � �
LL" �/ ��11 � C C.LI CC � r "' G.
W '.:: '.;: Z � �
CLi1SSIFICATION AND DF.SCKIPTION z � * � � � � ¢ � � �
F ;z
� F. ;�; ^ � �, ::.] �, :� � Z
�:..i � p„ '� �, x :/; i
"1 � � � ;�= � � CG < < �
�
O� Q �: w 3 .� z
a. �%
2" asphalt concrete over 7" aggregate base ;1;ti;• 0
.1rti��
•ti•ti•• _
.�y:tif �
.l.f.
Fill: Grayisl� brown, Clayey Sand/Sandy Lean Clay, moist, Dense/ SC/ 1
fine to coarse sub-rounded to sub-angular gravels, fine to Very CL 1
medium grai�led, low to moderate plasticity fines. Stiff 1 39 16
5 .
1
1
1 �l l�
Bay Mud: Gray, Fat Clay, moist, fine grained, high plasticity, Soft CH 1
shell fragments. to ■
� Liquid Li�nit = 66, Plasticity Index = 36. Firm 10 1 9 42
Brown, Clayey Sand with Gravel, moist, fine to medium Dense SC 1
grained, fine to coarse sub-angtilar to sub-rounded gravel, to 1
low plasticity fines. Very 1 68 17
Dense I
I
15 I �-� 14
1 Ground ��ater measured at ?0 feet after drillin��. Zp 1
Continued on Next Page
EXPLORATORY BORING LOG EB-1 BORING EB-1
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE PAGE 1 OF 3
BURLINGAME, CALIFORNIA APRIL 2020
PROJECT NO. 5047-1
,ROMIG
ENGINEEFIS
DRILL TYPE: Mobile Drill B-40 with 8" Hollow Stem Auger LOGGED BY: EHD
DEPTH TO GROUND WATER: 20' SURFACE ELEVATION: 5' DATE DRILLED: 2/13/20
N
� ^ *-.
�• r�. � , �- L�.
�J v "y� � '� :/=
',zZ,'i � bf1 G:: � 'w�,`i C� n z "' a.
�--' �„ 0"' a'-' i:r :7: �;; C �
� C .� �- �' � E-- ;.� � �-
CLASSIFICATION ANll UI;�SCRIPTION z � � � � ,� z � o � �
,J �, v; �, a: :� �, z
:Z; � "� p,,, � � !: i
:� v; z v; p ;;.a ^ r.�.', '= z
1 Z � v� ',� C � E ¢ '
�
� p � v; z 3 - z
x � s
Brown, Sand Lean Clay, moist, fine to medium grained sand, Very CL 20 1
moderate plasticity. Stiff ■
_ 1 � � ?4
■ Liquid Limit = 48, Plasticity Index = 27.
25
Brown, Clayey Sand/Silty Sand, moist, fine to coarse Very SC/ � 1
grained, fine sub-angular to sub-rounded gravels, Dense SM : 1
interbedded clay througl�out, low plasticity� fines. a; 1 88 16
.
` -
.�
e.
..
,�
�.
.
a
a -
�
� 30
" I
a�
�� I
�� I 50/5° 17
�,
�,
�
Q
b�
��
♦
��
Q�
�
A
� �5
v. �
♦� I
�
a` I 64 l�
.
b�
a�
�
�.
.e
a�
a�
b�
Q
a`� 40
Continued on Next Page
EXPLORATORY BORING LOG EB-1
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
BORING EB-1
PAGE 2 OF 3
APRIL 2020
PROJECT NO. 5047-1
,ROMIG
E N G 1 N E E R S
DRILL TYPE: Mobile Drill B-40 «�ith 8" Hollo�� Stem Auger LOGGED BY: EHD
'
DEPTH TO GROL'ND WATER: '?0' SURFACE ELEVATION: 5' DATE DRILLED: 2/13/20
N *
�" "FG' ¢ -- ^ ," ._
Z Q � `� F^ > 3 �, U s
� f� � a � �+ ,�,�, z c:
,-�j,� � � �^ � :�i F- �i [= �i �
CLASSIFICATION AND DESCRIPTION z� *� � ,,., z � z N �
v; ��� f � z
u;� '� � � �'�-, a. � x �: w
z � „ ,-:. � � ` �
a W Q ;r p Q � ¢ ¢ ;,
C p Q ;�: z 3 = z
� � �
Brown, Clayey Sand/Silty Sand, moist, fine to coarse grained, Dense SC/ �� 40 I
fine sub-angular to sub-rounded gravels, interbedded clay SM � �
throughout, low plasticity fines. � I 46 17
�
�,
b�
��
a•
,.
Q
q�
'�
Q
*� 45
�
..
.
o�
..
3`
o`
a•
a•
.�
�
��
�
• I
a' I,
`• 50 �1 16
Bottom of Boring at 50 feet.
55
Note: The stratification lines represent the approximate
boundary between soil and rock types, the actual
transition may be gradual.
*Measured using Torvane and Pocket Penetrometer devices.
60
EXPLORATORY BORING LOG EB-1 BORING EB-1
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE PAGE 3 OF 3
BURLINGAME, CALIFORNIA APRIL 2020
PROJECT NO. 5047-1
,ROMIG
ENGINEERS
DRILL TYPE: Mobile Drill B-40 with 8" Hollo��� Stem Auger LOGGED BY: LHU
DEPTH TO GROUND WATER: 19.5' SURFACE ELEVATION: 6' DATE DRILLED: 2/13/20
N
� Q � _ w .
�. '�' ,
z � � �%.7 C� �' � � F" � i
a cq �.' � z �
s � � � � � r- � � �, �
CLASSIFICATION AND DF.SCRIPTION � � F" �. z z z z �
¢
� "a U" � L:7 r' 'v � Z
z � Li: V `"� � � � 0.' ✓; 'a.
� � C � � � � ... � � ^
R.'
� p Q ;�: z 3 _ z
T,
a. '✓
3" asphalt concrete over 7" aggregate base :ti?1f• 0
.ti�tir•
.1�{r�
.11ti?�
.l.J.
Fill: Grayish brown, Sandy Lean Clay, moist, fine to medium Very CL 1
�rained sand, fine to coarse sub-angular to sub-rounded Stiff 1
gravels, low to moderate plasticity. to 1 29 19
Hard
5
1
1
1 �8 ?0
Bay Mud: Gray, Fat Clay, moist, fine to medium grained sand, Soft CIl I
moderate to high plasticity, shell fragments. I
I � ?7
1
Brown, Clayey Sand/Silty Sand, moist, fine to coarse grained, Medium SC/ e 1
fine to coarse sub-angular to sub-rounded gravels, low to Dense SM a; 10 1 17 5-�
moderate plasticity fines. b; I
a I
� 23% Passing No. 200 Sieve. � �� 1 18
.. -
��
W I
Q� I^63
Q � �9 �6
�R.
�
�..
Brown, Clayey Sand/Sandy Lean Clay, moist, fine to medium Medium SC/ 15
grained, tine sub-angular to sub-rounded gravels, moderate Dense/ CL I
plasticity fines. Very I
� 48% Passing No. 200 Sieve. Stiff 19 19
1 Ground water measured at 19.5 feet after drillin<�. 1
y 20
('ontinued on Next Page
EXPLORATORY BORING LOG EB-2 BORING EB-2
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE PAGE 1 OF 3
BURLINGAME, CALIFORNIA APRIL 2020
PROJECT NO. 5047-1
,ROMIG
ENGINEEi:B
DRILL TYPE: Mobile Drill B-40 ��ith 8" Hollow Stem Auger LOGGED BY: EHD
DEPTH TO GROUND WATER: 19.5' SURFACE ELEVATION: 6' DATE DRILLED: 2/13/20
�,
� � � *-- *.,
z� b�A i.:..7 Ci � � x [— � o:
a x
� � � � � � � � H v �
CLASSIFICATION AND DESCRIPTION �= �' �' � z ¢ o � �
� h �i � � � u? ��„ c.� � z
�
U v: Z � � w � � `�' z
� 1 � � c% Q � cG ¢ ¢ V
� p � ;�; z 3 � z
� � s
Brown, Clayey Sand/Sandy Lean Clay, moist, tine to medium Medium SC/ 20 1
grained, fine sub-angular to sub-rounded gravels, moderate Dense CL 1
lastici fines. 1 30 17
Brown, Silty Sand with Gravel, moist, fine to coarse grained, fin Dense SM �a�� I
��� I
sub-angular to sub-rounded gravels. to e�;
Very ,Q,�, I 3�
Dense �¢`b�
�.�,
�..�,
aea.
,Q.,.
��e�.
,•�• 25
ti�.w I
���e.
����a
� 12% Passing No. 200 Sieve. b,�.� �
�"�e I 3 9 16
.eb.Q
.a.�
.,�,.
��q��
�fa�2
�Q.�a
����
�� ,u
��4�y
���
�v.w
�n��j
��4�� � �
�w��
�Qa� I
'K�b�
�ey� I
�A� p 7
QQ� I O� 1 O
Zi
�b\`O.
`p�\
\Q�\\
\`b.\\
�4�[�
'q b�
rQy�
�v.�.
wv.b�
�`w
��� 35
.�Q,.
��..� �
.�eb.
�,tr.. I
.g�w
����' I 64 19
..�,a
�.�u
��0�2
�Qa�
���
����
y�f\
���
���
���
�2��n
�e�Q
�e`�. 40
Continued on Next Page
EXPLORATORY BORING LOG EB-2
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
BORING EB-2
PAGE 2 OF 3
APRIL 2020
PROJECT NO. 5047-1
,ROMIG
E N G 1 N E E R S
DRILL TYPE: Mobile Drill B-�10 �ith 8" Ilollo�i Stem Auger LOGGED BY: EHll
DEPTH TO GROUND WATER: 19.5' SURFACE ELEVATION: 6' DATE DRILLED: ?/13/20
�,
� ' z *. �
>• x < . � u..
� � c, � 3 _ � v
,�.,�z..l v c�r� Gw C w � �? c " _
f � � � � � � � z � �
CLASSIFICATION AND DF,SCRIPTION z� �� � ,.,, z ¢ z y �
�- � � z
� � w � a � s �-
.� Z � `i' C � � � � � �
U
O p � v¢,� z 3 �' z
� �
Grayish brown, Fat Clay, moist, fine grained sand, higl� Sh � CH 40 I
plasticity. I
I 13 45
45
Brown, Clay�ey Sand ��ith Gravel, moist, fine to coarse Dense SC
grained, tine to coarse sub-angular to sub-rounded gravels,
low plasticit}' tines.
1
� 19% Passing No. 200 Sieve. �
50 � � 19
Bottom of Boring at 50 feet.
5_5
Note: The stratiiication lines represent the approaimate
boundary between soil and roch types, the actual
transition may be gradual.
*Measured using Tor��ane and Pocket Penetrometer de��ices.
60
EXPLORATORY BORING LOG EB-2 BORING EB-2
BURLINGAME BAY OFFICE BUILDING AND PARKINCJ STRUCTURE PAGE 3 OF 3
BURLINGAME, CALIFORNIA APRIL 2020
PROJECT NO. 5047-1
,ROMIG
E N G 1 N E E R S
,��_
��i� , i�
���r�
Net Area Ratio .8
2 �
d I
W ���
0
10
20
30
40
50
60
70I
Romig �gineers
Project Burlin�ame gay New Office Building Operator JM-BB
Job Number 5047-1 Cone Number DDG1489
Hole Number CPT-01 Date and Time 2/11/2020 8:07:25 AM
EST GW Depth During Test _ 8.00 ft _ _
C PT DATA
80'
__ 90
1- sensitive fine grained ■ 4- silty clay to clay
■ 2- organic material ■ 5- clayey silt to silty clay
■ 3- clay ■ 6- sandy silt to clayey silt
i(1f1P II P��Fm iiiiiiii ii
Filename _ _ SDF(372).cpt
GPS
Maximum Depth 60.53 ft
- - — ---�- � -
, O
J 2 n
■ 7- silty sand to sandy silt ■ 10 - gravelly sand to sand
8- sand to silty sand �q 11 - very stiff fine grained (')
9- sand ■ 12 - sand to clayey sand (*)
S"Soil hPhavior tvnP and SPT hased on data from 11BC-19R3
„,�, Romig Engineers
� I I I' � II project Burlingame Bay New Office Building Operator JM-BB
"`��' Job Number 5047-1 Cone Number DDG1489
Hole Number CPT-02 Date and Time 2N1/2020 8:58:23 AM
EST GW Depth During Test 5.00 ft
Net Area Ratio .8
Filename SDF 373 .c t _
GPS
Maximum Depth 60.53 ft
� ---- - - �
C PT DATA o
w� I' TIP I'J 2�
FRICTION Fs/Qt SPT N I O W)-
� v 0 TSF 700 0 TSF 18 0 % 10 0 p � m~
�— _
-� i �_ _ _ — � i , � � .- T t i -��,� _��,-� i T - i --- �— , 35
- � � .� — - . T
� --�� ! j - I I I I
10 rI� � � ��
-- - �- --�
- �
�
20 I
4� � -
30 �
I
40 `- — - _ `- I
i — t � -
�
�
i I
50I I
�- - - +
'II z- - I - �
60I -- -- -
�
I
�
�o
�
so
_ — - +- —
i
so — — ' �. — �- ' � �
�
+
— - —�
I
— --+
�
i
1- sensitive fine grained ■ 4- silty clay to clay ■ 7- silty sand to sandy silt ■ 10 - gravelly sand to sand
■ 2- organic material ■ 5- clayey silt to silty clay 8- sand to silty sand ■ 11 - very stiff fine grained (”)
■ 3- clay ■ 6- sandy silt to clayey silt 9- sand
_ _ _ ■ 12 - sand to clayey sand (`)
Cnr 15r`—�rPd � hel—vne �T h .�i da __� U�
I II��I� II'i
,��, Ro 'mig �ngineers
i,il,' � II Project Burlingame Bay New Office Building Operator _ JM-BB
�''""' Job Number 5047-1 Cone Number DDG1489
Hole Number CPT-036 Date and Time 2/11/2020 10:32:21 AM
EST GW Depth Duri�Test __ 4.00 ft _
Net Area Ratio .8
— i - —
�
_
�
a
� � TIP
—�
10
20
30
40
50
60
70
80
90
1 - sensitive fine grained
■ 2 - organic material
■ 3 - clay
Cnne Size 15r.m snu�rPd
IIIIIIII IIIIII I II III IIIIIIIII II
C PT DATA
■ 4- silty clay to clay ■ 7- silty sand to sandy silt ■ 10 - gravelly sand to sand
■ 5- clayey silt to silty clay 8- sand to silty sand ■ 11 - very stiff fine grained (')
■ 6- sandy silt to clayey silt 9- sand ■ 12 - sand to clayey sand (*)
SSnil hehavinr tvne and SPT hasPd on dat� frnm 11BC-19R3
Filename SDF(376). �t
GPS
Maximum Depth 61.35 ft
�
0
>
ow}
c� m �
FRICTION Fs/Qt SPT N I
�� Romig Engineers
I I ' � I Project Burlingame Bay New Office Building Operator ,1M-BB
� Job Number 5047-1 Cone Number DDG1489
Hole Number CPT-04A Date and Time 2/11/2020 12:27:38 PM
EST GW Depth During Test _ _ 4.00 ft
Filename SDF�378).cpt
GPS
Maximum Depth 84.97 ft
SPT N
10 0
, i—T, i -i
L 1 ' _ � 1 �_ : �_ ' ' �L__� 1�_ � �
■ 7- silty sand to sandy silt ■ 10 - gravelly sand to sand
8- sand to silty sand � 11 - very stiff fine grained (')
9- sand ■ 12 - sand to clayey sand (')
� hPl--vnP �PT h -�+ da�.r—� lJ��
�
I O
>
I -� = d
3501� O m ~
� 1- sensitive fine grained ■ 4- silty clay to clay
■ 2- organic material ■ 5- clayey silt to silty clay
■ 3- clay ■ 6- sandy silt to clayey silt
Co�— 15r--�rec�
��, Romig tngineers
I I' � I I Project Burlin�me Ba�r New Office Building Operator JM-BB
''i'��'"" Job Number 5047-1 Cone Number DDG1489
Hole Number CPT-05 Date and Time 2/11/2020 2:17:53 PM
EST GW Depth During Test __ _ 4.00 ft __
Net Area Ratio .8
�
_
�
d
� � TIP
0
10
20
30
40
50
60
70
80
C PT DATA
—� �
0
>
o w }
350 �� c� m ~
__ 9U ; �-1 1 � _ � L_ � i � � � 1 -�- - � 1- ' I _ _i � � � � -- - L-- -- � -- �
1- sensitive fine grained ■ 4- silty clay to clay ■ 7- silty sand to sandy sitt ■ 10 - gravelly sand to sand
■ 2- organic material ■ 5- clayey silt to silty clay 8- sand to silty sand ■ 11 - very stiff fine grained (*)
■ 3- clay ■ 6- sandy silt to clayey silt 9- sand ■ 12 - sand to clayey sand (*)
^.nna Si�e 15r.m smiarP�1 SSoil hPhavior tvne and SPT hased nn data from U6C-19R3
IIIIIII IIIIII IIII III IIIIIIIIIIIII
Filename _ SD�79�.cpt _
GPS
Maximum Depth 80.54 ft
�,�
FRICTION Fs/Qt SPT N
„,� Romig Engineers
��� ' � Project Burlinc�ame Bay_New Office Building Operator �M_gg
'” �'' Job Number _ 5047-1 Cone Number DDG1489
Hole Number CPT-O6 Date and Time 2/12/2020 8:04:56 AM
EST GW Depth Durin9 Test ___ 12.20 ft
Net Area Ratio .8
�
2 I
�
�
o� I
_ 0
0 � -.
�
10 - -' �
20
30
40
50
60
70
80
TIP
TSF
FRICTION
C PT DATA
— 90 _ � � � � � �_I � — L
� 1- sensitive fine grained ■ 4- silty clay to clay
■ 2- organic material ■ 5- clayey silt to silty clay
■ 3- clay ■ 6- sandy silt to clayey silt
Cor 1.5c—�retl� — -- —
Fs/Qt
Filename SDF(380).cpt
GPS -
Maximum Depth 70.87 ft
SPT N
--� �
i o
>
� J = �
350 a O m ~
■ 7- silty sand to sandy silt ■ 10 - gravelly sand to sand
8- sand to silty sand �w 11 - very stiff fine grained (*)
9- sand ■ 12 - sand to clayey sand (')
� hPf—vne : =T h —� da�.�----� U� :�
��, Romig �gineers
I II ' � I I Project Burlingame BaY New Office Building Operator JM-BB
� Job Number 5047-1 Cone Number DDG1489
�1►y"
Hole Number CPT-07 Date and Time 2/12/2020 9:16:15 AM
EST GW Depth During Test 12.00 ft
2 I
H
a
w�
�" o
-- o _ a =-+ = T
10
20
30
40
50
60
70
80
_ _ 90J
1 - sensitive fine grained
� 2 - organic material
■ 3 - clay
�iiiii iilii li� .m cniiaiiiii
■ 4- silty clay to clay
■ 5- clayey silt to silty clay
■ 6- sandy silt to clayey silt
Filename _ SD�1�.cpt
GPS
Maximum Depth 55.12 ft
■ 7- silty sand to sandy silt ■ 10 - gravelly sand to sand
8- sand to silty sand ■ 11 - very stiff fine grained (")
9- sand ■ 12 - sand to clayey sand (*)
S"'Snil hehavior tvne and SPT hased nn data from 11BC-19R3
Net Area Ratio .8
APPENDIX B
LABORATORY TESTS
Samples from the subsurface exploration were selected for tests to help evaluate the
physical and engineering properties of the soils. The tests perfonned are briefly
described below.
The natural moisture content was determined in accordance with ASTM D2216 on nearly
all samples recovered from the borings. This test determines the moisture content,
representative of field conditions, at the time the samples were collected. The results are
presented on the boring logs at the appropriate sample depths.
The amount of silt and clay-sized material present was determined on three samples of
soil in accordance with ASTM D422. The results are presented on the log of Boring EB-
2 at the appropriate sample depths.
The Atterberg Limits were detennined on two samples in accordance with ASTM D4318.
The Atterberg Limits are the moisture content within which the soil is workable or
plastic. 'I'he results of these tests are presented in Figure B-1 and on the log of Boring
EB-1 at the appropriate sample depths.
One-dimensional consolidation test was perfonned on one sample of soil in accordance
with ASTM D2435. The result of this test is presented on Figure B-2.
An R-value test was perfonned on one sample of surface soil from the site to provide data
for pavement thickness design. The R-value test was performed in accordance with
California Test Method 301-F. The results of this test are presented on Figure B-3 in this
Appendix.
The following corrosion potential tests were performed by Cooper Testing Laboratory on
three samples of subsurface soil fro�n the site: resistivity, pH, chloride content, sulfate
content, and Redox Potential (Oxidation/Reduction Potential). The test methods that
were used and the results of these tests are included in this appendix. The results of lhese
tests are presented on Figure B-4.
.•. .•. .•. .•. .•.
,ROMIG
ENGINEEFaS
60
50
�
�
0
X 40
W
�
z
} 30
E-
U
H
Q 20
J
a
io
�
4
0
C H ��
o �•
•P
■
CL
�
MH
or
OH
c� o� nn� ML or OL
ML
0 10 20 30 40 50 60 70 80 90 100
LIQUID LIMIT (°/a)
Passing USCS
Chart Boring Sample Water Liquid Plasticity Liquidity No.200 Soil
Symbol Number Depth Content Limit Index Index Sieve Classitication
(feet) ( ercent) ( ercent) ( ercent) ( ercent) ( ercent)
■ EB-1 9-9.� �? 66 ;6 CH
♦ F.B-1 20-21.5 24 48 27 CL
PLASTICITY CHART FIGURE B-1
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA PROJECT NO. 5047-1
,ROMIG
ENGINEEqS
CQDPER Consolidation Test
ASTM D2435
Job No.: 192-3=� Boring: EB-1 Run By; I,1D
Client: Romig Engineers 5ample: Reduced: PJ
Project: 50�7-1 Depth, ft.: 1G-'12(Tip-'11 ; Checked: PJ?DC
Soil Type: Olive Brown Sandy CLAY? Clavey S�.ND Date: 3?6;2U20
Strain-Log-P Curve
o.o
So
10.0
— 15.0
N
����11
25.0
__ .,,,�1
��..
�,,�
�,_ I�.
������, ��
��..__ 1�.
1��11�1i�
1 �
1000
EffectiveStress� p9
10000
100000
Assumed Gs 2 ?5
Moisture °/o:
Dry Density, pcf:
Void Ratio:
% $8tUf8tlOf1:
100
Initial Final
17 5 16 7
109.4 117 7
0 569 O �159
Remaiks:
CONSOLIDATION TEST FIGURE B-2
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA PROJECT NO. 5047-1
�ROMIG
ENGINEElaS
CQDPER R-val ue
C TM 301
CTL Job No : 192-3F2 8orin = EB-1 Reduced B,v: RU
Client: Romig Engineers Sample: BelowAB checkedBv: PJ
Project Number: 5047-1 De th= Date= 2.+2�;2020
Pro ect Name= Burlin ame Bay R-Value 16
Soil Description_ Dark Brown Sandv CLAY w?' Gravel
Remarks: Expansion 0
Pressure
Specimen Designation A B C D E
Com actor Foot Pressure si 140 120 1200
Exudation Pressure si 378 678 248
Exudation Load {Ibf) 4750 8520 3116
Hei ht After Com action in 2��F� 2.4F� 2 F�7
Ex ansion Pressure sf 0 0 0
Stabilometer @ 2000 118 98 130
Turns Dis lacement 3_34 3_16 4_00
R-value 21 33 13
Corrected R-Value 21 33 13
Moisture Content °�0 13.2 11.8 15_0
Wet Densitv (pcf) 137_7 141_3 135_7
Dry Densit,y (pcf) 121.7 126.4 117_9
1,;,; 4E•�i�;ri•:�i�Fi---_,�ue,-F- ;��ie
� � ,
•E��rlati��i�Fi�..�_u�„ E•��i�a�:�i�
.. i _ F���__in�
�� __ .__ --
- -- -- -- - _ --- -- _ . -- �-
—�- . � . � , - , — - -
___ �—._ __.. - - —._ __ _ � _
i: , , � , , _ - -
i . . _. - - ' -- — � - � . � ---r .
C'-I _ .. ' _-__ '_._ ' _ -__- - ___ -.i __. . .. ._. ..
. i �
i
"_ _ -� -__ - _ "'.. . ._'-_-"
_ .' ___ "._..I _-... _ . _._ ._.-_.. ..
�, _ . , , __-_ — .i�. .
. . , � , ,
_— -- -- � t
� i - ; :
l: ,
I, : � f 1'> :
��_ - - _ __ _ _--� - : -__ -- .
��: . � . . _ . . -��: . _ . . - . . .
R-VALUE TEST
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
,ROMIG
E N G 1 N E E R 5
FIGURE B-3
APRIL 2020
PROJECT NO. 5047-1
..� .�I � . . ,; r �
`I� ... . . . . ' ' � ' :.i :, . �i. .. ' I,.il, 1 4,l �". ��I I �� I l ,
;i I
i 1 4 J I i'r, � Yi.
' ,�� � ' cvU��R ' Corrosivi�y Tests summary ' . I! '' � I I ` "+ ";'' �'���'y{I�'�i��,�f�F��}����
;, �
I �� I. ' ' I I �, � , I
i''� i�'� ��,', � I � � � :� r I � c'� , , T ��: � i I�r,,�; 1� �!' �i' � I, � i�����i; '.��� i i i �i i.qY��` i�� '(
� a `'' ,,. � � � ,. ,' t . + J:
CTL# 132-3 q , Y: , • , '
� � „ Date: — 2i21?202D , Te . • . , � , . , , .. , .. , a, � ,,
sied B PJ Ch�cked: PJ
Gient Romip Enpineers Pr ect: Birlir�ame Bav Prnj. No: 5D�-1
12ema rk s:
, , Resistivily � 15S'C {Dfimcm} Chtoridr Sulfate �I, . _ ORP SuI{�d�e Maistu�e ,' '"' ; , ;
i � .
r ,. _
As Fiec. Min Sat vn f m k 4i tRexkuF o.�i�vi,a AtTest _
ion ar
,w�;h r ';� , , � SalYisual0escri ian
Borii . Sam k. No. De th. ft n5l?A r57 .. C�i ea3 DryWt 6ryN�lt 6ry]q�7 . h.�'"T,NG51 ��rtv} AtT.cr Leed 96 _ T, Pt
� '
: , �
� n:,-r�i cs� nsr,�� �s3� nsr�� nc3n 0.5T�i �, ,.-,r.�. �-co � --,".T^^�. -
TQ,❑ -e j.M.u. F:aa .nsne �zz�a � T
EB-1 - &5 - - 1,18b 119 758 : 0.075�6 € 7.S 311 �1 : Negetiwe ': 11,2 '��rYQ'akGrayish&rownCiay�y
.............................:..........................._;.............................i.........................:.................................d..............
........... s ............................:.........................:.........................:.........................:.....
....................:...................:......................... a.......
t : : : � ' .....................SkNDwiGat�l
l.VicicV�lVll Y 1L+a1 �U1V11VlAKY
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
FIGURE B-4
APRII, 2020
PROJECT NO. 5047-1
APPENDIX C
PILE CAPACITY ANALYSES
Figure C-1 - Allow Capacities for 14" Square PCPS Pile
Figure G2 - Allow Capacities for 16" Auger Cast Pile
Figure C-3 - Lateral Detlection Curves, Free Head Condition, 14" Pile
Figure C-4 - B�nding Moment Curves, Free Head Condition, 14" Pile
Figure C-5 - Shear Curves, Free Head Condition, 14" Pile
Figure C-6 - Lateral Deflection Curves, Fixed Head Condition, 14" Pile
Figure C-7 - Bending Moment Curves, Fixed Head Condition, 14" Pile
Figure C-8 - Shear Curves, Fixed Head Condition, 14" Pile
Figure C-9 - Lateral Deflection Curves, Free Head Condition, 16" Pile
Figure C-10 - Bendin� Moment Curves, Free Head Condition, 16" Pile
Figure C-11 - Shear Curves, Free Head Condition, 16" Pile
Figure C-12 - Lateral Deflection Curves, Fixed Head Condition, 16" Pile
Figure C-13 - Bending Moment Curves, Fixed Head Condition, l6" Pile
Figure C-14 - Shear Curves, Fixed Head Condition, 16" Pile
.•. .•� .•. .•. .'.
• • • • •
,ROMIG
ENGINEERS
ALLOWABLE CAPACITY FOR 14-INCH SQUARE PILE
10
20
30
m
d
�
r 40
a
m
0
50
�
70
80
-100
0
`\ LEGEND
� Allowable Compression Capacity
♦
�
` ---• Allowable Uplift Capacity
�
� * Assumed Top of Piles at about 4 feet
� below building finished floor elevations
♦
♦
�
♦
�
�
\
♦
�
♦
�
�
♦
�
�
\
�
♦
Allowable Pier Capacity (kips)
-50 0 50 100 150 200 250 300 350
ALLOWABLE CAPACITIES FOR 14-1NCH SQUARE P1LE FIGURE C-1
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA PROJECT NO. 5047-1
,ROMIG
E N G I N E E R S
ALLOWABLE CAPACITY FOR 16-INCH AUGERCAST PILE
10
20
30
m
m
�
L 40
a
m
❑
50
[:3i1
70
80
-100
0
�
� LEGEND
� Allowable Compression Capacity
�
�
� ---• Allowable Uplift Capacity
�
� * Assumed Top of Piles at about 4 feet
� below building finished floor elevations
�
�
�
�
♦
�
♦
♦
♦
♦
♦
♦
�
♦
�
♦
�
♦
�
Allowable Pier Capacity (kips)
-50 0 50 100 150 200 250 300 350
ALLOWABLE CAPACITIES FOR 16-1NCH AUGERCAST P1LE FIGURE G2
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA PROJECT NO. 5047-1
,ROMIG
E N G 1 N E E R S
LATERAL DEFLECTION VS. DEPTH
14-inch Square PCPS Pile, Free Head Condition
Delfection (inch)
-0.1
0 -
5 -
�
'� O 1 .
�I
I
15 �
� 20 �
_ .
�, .
�
d
J
Ni
'a 25 •
30 �
i
35 *
40 i
45 � -
LATERAL DEFLECTION CURVF,S - FREE HEAD CONDITION FIGURE C-3
BURLINUAME BAY UFFICE BUILDING AND PARKING STRUCTURE APR1L 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
ENGINEEFIS
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3
BENDING MOMENT VS. DEPTH
14-inch Square PCPS Pile, Free Head Condition
Bending Moment (kips-in)
-500
0�
N�
�
10 rt
15 �
� 20 -
L �
� �
C
J I
Gf {
a 25 �
30 ,
35
40 �
45
BENDING MOMENT CLIRVES - FREE HEAD CONDITION FIGURE C-4
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
E N G 1 N E E R S
0 500 1000 1500 2000
SHEAR VS. DEPTH
14-inch Square PCPS Pile, Free Head Condition
Shear (kips)
0
5
10
15
d 20
r
m
�
d
J
N
a 25
30
35
40
!�.�
SHEAR CURVES - FREE HEAD CONDITION FIGURE C-5
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
E N G 1 N E E R S
-30 0 30 60
LATERAL DEFLECTION VS. DEPTH
14-inch Square PCPS Pile, Fixed Head Condition
5
10
15
� 20
r
o�
�
d
J
d
a 25
30
35
40
�7
LATERAL DEFLECTION CURVES - FIXED HEAD CONDITION FIGURE C-6
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
ENGINEERS
Delfection (inch)
-0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
0 . . . . , - - --�— '� - �'—�--# � . . . �_ :�—�� ._ _� ._ � _,__ . _ . � _ , . . . . . , _ } _ ,
BENDING MOMENT VS. DEPTH
14-inch Square PCPS Pile, Fixed Head Condition
Bending Moment (kips-in)
-2500
0 --
10 �-- -
�
20 —
;, 30 !
d
�. �
r
�, .
�
d
J
07 -
'a
40 -
�
,
50 �
�
60 � --
1
70 -
BENDING MOMENT CURVES - FIXED HEAD CONDITION FIGURE C-7
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APR1L 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
E N G I N E E R S
-2000 -1500 -1000 -500 0 500 1000 1500 2000
SHEAR VS. DEPTH
14-inch Square PCPS Pile, Fixed Head Condition
Shear (kips)
-60
0 - -
10 Y --
�I
I
20 �
�, 30 -
d
� �
� ;
� i
d
�
'a
40 — -
50 -
1
60 -
70 —
SHEAR CURVES - FIXED HEAD CONDITION FIGURE C-8
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
ENGINEERS
-30 0 30 60 90
LATERAL DEFLECTION VS. DEPTH
16-inch Diameter Auger Cast Pile, Free Head Condition
-0.1
0 -�
5 �
,
10 J
15 �
� 20 -
r �
rn
c
d
J
GI
d 25 �
�
7
30 -
I
35 �
i
40 �-
�
�
45
LATERAL DEFLECTION CURVES - FREE HEAD CONDITION FIGURE C-9
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
E N G I N E E R S
Delfection (inch)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
BENDING MOMENT VS. DEPTH
16-inch Diameter Auger Cast Pile, Free Head Condition
Bending Moment (kips-in)
-500
0 �
5 �
1
10 - -
15 t- -
�
� 20 �
L
O) I
C
N
J
�
'a 25 -
30 �
,
35 !
C�i�
{
45 -
BENDING MOMENT CLJRVES - FREE HEAD CONDITION FIGURE C-10
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
E N G I N E E R S
0 500 1000 1500
SHEAR VS. DEPTH
16-inch Diameter Auger Cast Pile, Free Head Condition
Shear(kips)
0
10
20
30
40
d
�
t
�' S0
�
d
�
d
'a
.1
70
:�
.�
100
SHEAR CLiRVES - FREE HEAD CONDITION FIGURE G11
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
E N G 1 N E E R S
-60 -30 0 30 60
LATERAL DEFLECTION VS. DEPTH
16-inch Diameter Auger Cast Pile, Fixed Head Condition
-0.1
0 -
5 --
�
1
10 -
15 -
�
w 20 �i
_
�
�
d
�
d ,
a 25 ,
30 �
I
35 -
40 �
I
45
Delfection (inch)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
LATERAL DEFLECTION CURVES - FIXED HEAD CONDITION
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
,ROMIG
_ E N G 1 N E E R S
1 1.1 12
FIGURE G12
APRIL 2020
5047-1
I '
- - - - I � � .
BENDING MOMENT VS. DEPTH
16-inch Diameter Auger Cast Pile, Fixed Head Condition
Bending Moment (kips-in)
5
10
15
w 20
t
m
�
d
J
m
'a 25
30
35
40
45
BENDING MOMENT CURVES - FIXED HEAD CONDITION FIGURE G13
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE APRIL 2020
BURLINGAME, CALIFORNIA 5047-1
,ROMIG
E N G I N E E R S
-1500 -1000 -500 0 500 1000 1500
0 a � �— �i - -- -- - - - - - - � � - - �
SHEAR VS. DEPTH
16-inch Diameter Auger Cast Pile, Fixed Head Condition
Shear(kips)
0
5
10
15
� 20
r
�
�
d
J
d
a 25
30
35
40
45
SHEAR CURVES - FIXED HEAD COND[TION
BURLINGAME BAY OFFICE BUILDING AND PARKING STRUCTURE
BURLINGAME, CALIFORNIA
,ROMIG
E N G 1 N E E R S
FIGURE C-14
APRIL 2020
5047-1
-50 0 50 100
APPENDIX D
LIQUEFACTION ANALYSES
To evaluate the potential for earthquake-induced liquefaction of the soils at the site, we
perfonned a liquefaction analysis of the CPT data using the methods described in the
2008 publication by Idriss and Boulanger titled "Soil Liquefaction During Earthquakes."
The results of our lic�uefaction evaluation and the details regarding the potentially
liquefiable layers are presented on the attached Figures D-1 through D-3.
�'. �'. �'. .'. �'.
• • • • •
,ROMIG
ENGINEERS
� ROMIG
� E N G 1 N E E R S
Project: Burlingame Bay OfFce Building and Parking Garage
CRR plot
w
s
�.+
Q
N
�
�,
L
n
N .
�
t
f
Overlay Cyclic Liquefaction Plots
FS Plot Liquefaction potential
w
L
d
N
�
0
s
io
is
zo
zs
30
35
� �
L
d
� 45
50
55
60
65
70
75
80
Vertical settlements
— C PT-01
C PT-02
� C PT-036
� C PT-04A
— C PT-05
— C PT-06
— C PT-07
FIGURE D-1 LIQUEFACTION ANALYSIS USING ROBERTSON 2009
0 0.25 0.5 0.75 I
CRR
0 0.5 1 1.5 2
Factor of safety
0 5 10 15
LPI
0 0.2 0.4 0.6 0.8 1 1.2
Settlement (in)
� ROMIG
� ENGINEERS
Project: Burlingame Bay Office Building and Parking Garage
�
r
a
v
�
0
5
io
�s
zo
zs
30
35
� �
L
a
� 45
50
55
60
65
70
75
80
FS Plot
0 0.25 0.5 0.75 1 0 0.5 1 1.5
CRR Factor of safety
Overlay Cyclic Liquefaction Plots
Liquefaction potential
�
L
n
a
�
2 0
5 10 15
LPI
Vertical settlements
�
L
a
a�
0
— C PT-01
C PT-02
— C PT-03B
� C PT-04A
— C PT-05
— C PT-06
— C PT-07
FIGURE D-2 LIQUEFACTION ANALYSIS USING IDRISS AND BOULANGER 2014
CRR plot
0 0.5 1 1.5 2
Settlenent (in)
� ROMIG
� E N G 1 N E E R S
�
Project: Burlingame Bay Office Building and Parking Garage
CRR plot
�
L
�
�
�
�,
L
a
v .
�
Overlay Cyclic Liquefaction Plots
FS Plot Liquefaction potential
w
L
a
v
�
2 0 5 10
LPI
15
0
s
io
is
zo
zs
30
35
� 40
t
a
� 45
50
55
60
65
70
75
80
Vertical settlements
— C PT-01
C PT-02
-a C PT-036
— C PT-04A
— C PT-05
— C PT-06
— C PT-07
FIGURE D-3 LIQUEFACTION ANALYSIS USING MOSS 2006
0 0.25 0.5 0.75 1
CRR
0 0.5 1 1.5
Factor of safety
0 0.5 1 1.5 2
Settlanent (in)
� ROMIG
� ENGINEERS
ROMIG ENGINEERS, INC.
1390 EI Camino Real, 2�d Floor
San Carlos, California 94070
Phone: (650) 591-5224
www.romigengineers.com