GEOTECHNICAL ENGINEERING REPORT

MLK STREETSCAPE IMPROVEMENTS PROJECT

MARTIN LUTHER KING JR. WAY

OAKLAND, CALIFORNIA

For

Wood Rodgers, Inc.

3301 C-Street, Building 100-B

Sacramento, CA 95816

By

PARIKH CONSULTANTS, INC.

1497 N Milpitas Blvd

Milpitas, CA 95035

(408) 452-9000

January 8, 2024 PARIKH Project No.: 2023-131-PAV

CONTENTS PAGE NO.

1.0 INTRODUCTION

2.0 SCOPE OF WORK

3.0 PROJECT DESCRIPTION

4.0 FIELD EXPLORATION

5.0 LABORATORY TESTING

6.0 GEOLOGY

7.0 SUBSURFACE CONDITIONS

8.0 LABORATORY TESTING

9.0 STRUCTURAL PAVEMENT SECTIONS

10.0 GRADING

11.0 BASELINE ENVIRONMENTAL INVESTIGATION

12.0 INVESTIGATION LIMITATIONS

LIST OF PLATES

Plate No. 1: Project Location Map

Plate No. 2: Boring Location Map

Plate No. 3: Geologic Map

APPENDICES

APPENDIX A: Boring Logs and Pavement Core Photos

APPENDIX B: Laboratory Test Results

APPENDIX C: Structural Pavement Section Calculations

APPENDIX D : Baseline Environmental Consulting - Limited Soil Investigation Report

GEOTECHNICAL ENGINEERING REPORT

MLK STREETSCAPE IMPROVEMENTS PROJECT

MARTIN LUTHER KING JR. WAY

1.0 INTRODUCTION

This report presents the results of our geotechnical engineering investigation for the proposed

MLK Streetscape Improvements Project (Project) in Oakland, California. The work was generally performed in accordance with our contract with Wood Rodgers, Inc. The project location map is shown on Plate No. 1.

2.0 SCOPE OF WORK

The purpose of this investigation was to evaluate the general subgrade conditions at the project site, and to provide structural pavement recommendations for the proposed roadway improvements. The scope of work performed for this investigation included a review of the readily available geologic literature pertaining to the site, field exploration, laboratory testing, engineering analysis of the data and interaction with the designer, and preparation of this report.

In addition, Baseline Environmental prepared limited Phase 2 testing for the subgrade samples to provide information for potential soil disposal from an environmental standpoint.

3.0 PROJECT DESCRIPTION

The proposed project includes various roadway improvements along Martin Luther King Jr. Way between 2nd and 12th Street. Improvements will include roadway paving/rehabilitation, removal of street parking, widening of sidewalks, buffered bike lanes, added turn lanes, and lighting.

4.0 FIELD EXPLORATION

The field exploration program consisted of advancing 6 exploratory borings (B-1 through B-6) to depths of 10 to 15 feet using a truck-mounted drill rig. The borings were drilled in traffic lanes along the existing roadway. The exploration locations are shown on Plate No. 2, Boring Location

Map.

The borings drilled and sampled at various depths using a Modified California sampler (2.5-inch

I.D. and 3-inch O.D.) or a Standard Penetration Test sampler (SPT, 2-inch O.D. and 1 3/8-inch I.D.

at shoe) under the impact of a 140-lb safety hammer with 30 inches drop. Bulk samples were obtained from soil cuttings from each of the borings between depths of about 1 to 5 feet.

Pavement cores were photographed and the supporting basecourse material was measured;

photos of the pavement cores are presented in Appendix A.

The drilling and sampling operations were observed by Caltrans Cultural Resources personnel for potential cultural artifacts of significance.

Job No. 2023-131-PAV (MLK Streetscape Improvements Project)

January 8, 2024

One drive sample was obtained from each of the borings for the Limited Phase 2 testing investigation by Baseline Environmental. Drive samples obtained for Baseline were driven below the pavement base course using a Modified California sampler cleaned with Tri-Sodium

Phosphate (TSP). Environmental samples were sealed, placed on ice, and transferred to Baseline at the end of the day under a chain-of-custody. Results of Baseline’s investigation are presented in Appendix D.

Geotechnical samples recovered from the borings were logged by our Staff Engineer, sealed, and transported to PARIKH’s Milpitas office for laboratory testing.

5.0 LABORATORY TESTING

Laboratory testing on samples recovered from the borings included moisture content, density, particle-size, and R-Value tests. Laboratory R-value testing was performed on the bulk samples recovered from Borings B-1, B-3 and B-5. The results of the laboratory index testing is presented on the Logs of Test Borings in Appendix A. A summary of the laboratory Sieve and R-Value

Appendix B.

6.0 GEOLOGY

According to the “Maps of Quaternary Deposits and Liquefaction Susceptibility in the Central San

Francisco Bay Region” by Witter, et al. 2006, Martin Luther King Jr. Way between 2nd Street and

12th Street is mapped as underlain by Dune Sand deposited during the Holocene and Latest

Pleistocene epochs (the past 11,700 years). The exploration encountered subsoil that is consistent with geological literature.

7.0 SUBSURFACE CONDITIONS

The borings generally encountered very loose to medium dense silty sand, at site. All holes were backfilled with cement grout per ACPWA permit conditions. Groundwater was encountered during drilling (December 2020) in Boring B-2 at a depth of 10.9 feet below ground surface (bgs).

The existing asphalt and concrete pavement thicknesses, base materials, and subgrade soils encountered in the borings are summarized in the following table.

Table 1 – Summary of Approximate Existing Pavement Sections and Subgrade Soils

Boring

No.

Boring

Depth

(feet)

Approx. Thickness of

Pavement Section

Base Course Material and

Thickness Subgrade Soil Description

B-1 15

5” (2”+1-1/2”+1-1/2”) AC

over 7” Concrete

2” Poorly Graded Sand (SP) Silty Sand (SM) medium dense, dark brown

B-2 15 10” AC

2” Poorly Graded Sand (SP)

Silty Sand (SM) medium dense, dark brown

B-3 15 9” AC

16” Poorly Graded Gravel (GP)

Silty Sand (SM) loose, dark yellowish-brown

B-4 15 6” (2”+4”) AC over 7”

Concrete

17” Poorly Graded Gravel (GP) Silty Sand (SM) loose, brown

B-5 10 5” (2”+3”) AC over 7”

Concrete

9” Poorly Graded Sand with

Gravel (SP) Clayey Sand (SC) very loose, dark yellowish-brown

B-6 10 5” (1-1/2”+3-1/2”) AC over

6” Concrete

2” Poorly Graded Gravel (GP) Poorly Graded Sand (SP) loose, yellowish-brown

Notes: AC: Asphaltic Concrete. Bracketed thicknesses indicate layer thicknesses where AC consists of more than one layer.

Please note that the existing pavement thicknesses presented in Table 1 are approximate and are for the locations explored. The exploration data and the findings should be used with caution for estimation purposes. Pavement sections and soil conditions may vary significantly during construction and may depend on history of construction and maintenance. The Logs of Test

Borings and photos of the existing pavement sections are presented in Appendix A.

8.0 LABORATORY TESTING

Results of the laboratory tests confirm the subgrade soils consist predominantly of silty fine sand.

Three (3) samples were tested for R-value. The R-value test results are presented in Appendix B and summarized in the following table.

Table 2 – Summary of R-value Test Results

Boring No. R-value

B-1 74

B-3 74

B-5 71

9.0 STRUCTURAL PAVEMENT SECTIONS

Based on the test results, an R-value of 40 is recommended for pavement design to account for variation in the subgrade soils. Per information provided by the designer, traffic indices (TI) of

8.5, 9.0, 9.5, 11.5 and 12.0 are used for the pavement section design for Martin Luther King Jr.

Way. The design of the pavement sections is generally in accordance with the State of California

Department of Transportation design procedures (conventional empirical method). The recommended flexible pavement design sections for the TIs are summarized in the following table.

Table 3 – Flexible Pavement Sections (Roadway, R-Value = 40)

TI

Option 1 Option 2

Full Depth HMA HMA AB

8.5 10.0” 5.5” 8.5”

9.0 10.5” 5.5” 10.0”

9.5 11.0” 6.0” 10.5”

11.5 13.5” 7.5” 13.5”

12.0 14.0” 8.0” 13.5”

1. HMA: Hot Mix Asphalt (Type A).

2. AB: Aggregate Base (Class 2) with R-value equal to 78.

At the City’s option, a 2” thick Open Graded HMA (no structural value) may be used on top to help surface drainage. Hot Mix Asphalt (HMA, Type A), Aggregate Base (AB, Class 2, with R-value

= 78) should conform to the Caltrans 2023 Standard Specifications in Section 39 and 26, respectively.

It is recommended that the pavement subgrade be scarified to a depth of at least 6 inches and moisture conditioned to 2% to 3% over optimum moisture content and re-compacted to at least

95% relative compaction per project specifications.

Reclaimed Asphalt Pavement. A portion of Type A HMA can be replaced by Reclaimed Asphalt

Pavement (RAP) in flexible pavement design for the Project. The RAP is specified in Section 39

“Asphalt Concrete” of the Caltrans Standard Specifications (2023). According to the Caltrans specifications, the RAP can substitute for part of the virgin aggregate in a quantity up to 25 percent of the aggregate blend. For Type A HMA using RAP, the maximum allowed binder replacement is 25.0 percent in the upper 0.2 feet exclusive of open grade friction course (OGFC) and 40.0 percent below. The Caltrans Standard Specifications should be referred to for preparation of Type A HMA using RAP.

10.0 GRADING

All grading and compaction operations should be performed in accordance with the project specifications. A representative from this office or regulating agency should observe all excavated areas during grading and perform moisture and density tests on prepared subgrade and compacted fill material.

Areas to receive fill should be clean of vegetation, shrubs, trees, and their roots greater than one

(1) inch in diameter. Areas of soft, organic or saturated soils could be encountered during site grading. Where such conditions are encountered, deeper excavation may be required to expose firm soils. Deeper excavation may also be required in areas of demolition of existing improvements.

Any fill materials imported to the project site should be non-expansive, relatively granular material having a Plasticity Index (PI) of less than 15 and a minimum Sand Equivalent (SE) of 10.

The maximum particle size of fill material should not be greater than 4 inches in largest dimension. It should also be non-corrosive, free of deleterious material and should be reviewed by the Geotechnical Engineer. Pavement subgrade should be compacted to minimum 95% relative compaction as per City standards.

The proposed Project is located along the existing streets. Traffic control is required to maintain traffic flow during construction. Many existing underground utilities are present beneath Martin

Luther King Jr. Way. The contractor should verify the utility lines, be aware of the existing conditions and plan the construction activities accordingly.

In our opinion, conventional equipment can be used to excavate the on-site soils. Subgrade pumping may be encountered during earthwork construction depending on the weather, moisture condition of the subsurface soils, and surface drainage conditions. Equipment mobility may also be difficult if the subgrade is wet. In which case, the subgrade soils may require reworking, aeration, or over-excavation and replacing with fabric and granular fill to facilitate earthwork construction.

To provide a working platform and stable support for structural pavement sections, the subgrade may be stabilized by over-excavating below the planned subgrade and replacing with base rock type of material over a layer of Subgrade Enhancement Geosynthetic fabric, such as Caltrans SEG

Class B1 (Caltrans Standard Specification, Section 96-1.02O, 2022). The actual depth of over-excavation depends on the actual field conditions during construction. The proposed structural pavement sections should then be constructed on top of the properly treated subgrade. The over-excavation and replacement with fabric and granular material is in addition to the design structural sections. It is intended to facilitate construction activities on poor and weak subgrade during construction, if required.

It is possible that unknown old, buried utilities or abandoned structures, concrete rubble, etc. are located along the project alignment. It might require special equipment and additional effort to remove these buried objects.

Prospective contractors for the Project should be advised to evaluate construction-related issues on the basis of their own knowledge and experience in local areas, on the basis of similar projects in other localities, or on the basis of their own field investigation on the site, considering their proposed construction methods and procedures. In addition, construction activities related to excavation and lateral earth support must conform to safety requirements of OSHA and other applicable municipal and State regulatory agencies.

11.0 BASELINE ENVIRONMENTAL INVESTIGATION

Baseline Environmental performed a Limited Soil Investigation for the site to evaluate potential soil contamination beneath areas of proposed project improvements for potential offsite disposal, and to support worker health and safety protocols during construction; results of their investigation are presented in Appendix D.

12.0 INVESTIGATION LIMITATIONS

Our services consist of professional opinions and recommendations made in accordance with generally accepted geotechnical engineering principles and practices and are based on our site reconnaissance and the assumption that the subsurface conditions do not deviate from observed conditions. All work done is in accordance with generally accepted geotechnical engineering principles and practices. No warranty expressed or implied, of merchantability or fitness, is made or intended in connection with our work or by the furnishing of oral or written reports or findings.

The scope of PARIKH’S services did not include any environmental assessment or investigation for the presence or absence of hazardous or toxic materials in structures, soil, surface water, groundwater or air, below or around this site.

Unanticipated soil conditions are commonly encountered and cannot be fully determined by taking soil samples and excavating test borings; different soil conditions may require that additional expenditures be made during construction to attain a properly constructed project.

Some contingency fund is thus recommended to accommodate these possible extra costs.

This report has been prepared for the proposed Project as described earlier, to assist the engineer in the design of this Project. In the event any changes in the design or location of the facilities are planned, or if any variations or undesirable conditions are encountered during construction, our conclusions and recommendations shall not be considered valid unless the changes or variations are reviewed, and our recommendations modified or approved by us in writing.

This report is issued with the understanding that it is the designer's responsibility to ensure that the information and recommendations contained herein are incorporated into the Project and that necessary steps are also taken to see that the recommendations are carried out in the field.

The findings in this report are valid as of the present date. However, changes in the subsurface conditions can occur with the passage of time, whether they are due to natural processes or to the works of man, on this or adjacent properties. In addition, changes in applicable or appropriate standards occur, whether they result from legislation or from the broadening of knowledge.

Accordingly, the findings in this report might be invalidated, wholly or partially, by changes outside of our control.

Respectfully submitted, PARIKH CONSULTANTS, INC.

Mark W. McKee, P.E., G.E. 2897 David Wang, Ph.D., P.E. 52911

Senior Project Engineer Senior Principal Engineer

P in e S t

7th St

F ro n ta ge

Rd

Matson Terminal

(SSA)

Oakland Global Trade &

Logistics Center

Oakland Intermodal

W Tower Ave

38th St 34th S t

32nd St

32nd St

M a n il a A v e

33rd St

T e le g ra p h A v e

B ro a d w a y

W MacArthur Blvd

MacArthur Fwy EBMUD Water

Treatment

Oakland Global Trade &

Logistics Center

Oakland Medical Center

P o s e y T u b e

11th St

16th St

W e b s te r S t

4th St th

A ve

17th St

24th St

24th St

13th St

W es t S t

W e s t S t

8th St

10th St

10th St

26th St W oo d S t

18th St

28th St

L in d e n S t

32nd St

U n io n S t

M y rt le

S t

30th St

F il b e rt

S t

F ra n k li n S t

C e n te r S t

Main St

34t h St

Middl e Harb or Rd

Le e S t

3rd St

B ru sh

S t

10th St

5th St

7th St

7th St

27th St

M a rk e t S t

M a rk e t S t

C a s tr o S t

A d e li n e S t

W Grand Ave

P er al ta

S t

17th St

T e le g ra p h A v e

Grand Ave

8th St

B ro a d w ay

B ro a d w ay

Nimitz Fwy

G ro ve

Sh af te r Fw y

Charles P.

Howard Terminal

Roundhouse Property

Jack London Square

South Prescott Park

Lakeside Park

West Oakland

Oakland th

S t

Buena Vista Ave

Atl antic Ave

O ri o n S t

Singleton Ave

F e rr y P t

V ik in g S t

C o n s titu tio n W a y

M a in

S t

W e b s te r S t

W e b s te r S t

College of Alameda

6t h Av e

4t h Av e

E 11th

S t

P e rk in s S t

San Rafael

San Francisco

San Leandro

Concord

Oakland

San Mateo Fremont

0 4,000

Feet

Scale: 1:24,000

Basemap source: ESRI Exported: 12/19/2023

Map Location

PROJECT LOCATION MAP

PLATE NO.:

MARTIN LUTHER KING STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

JOB NO.: 2023-131-PAV

Project Site Martin Luther King Jr. Way (2nd Street to 12th Street)

MARTIN LUTHER KING STREETSCAPE PROJECT

JOB NO.: 2023-131-PAV PLATE NO.: 1A

CORING LOCATION MAP

BORING LOCATION MAP

P in e S t

7th St

F ro n ta ge

Rd

Matson Terminal

(SSA)

Oakland Global Trade &

Logistics Center

Oakland Intermodal

38th St 34th St

32nd St

32nd St

M a n il a A v e

33rd St

T e le g ra p h A v e

B ro a d w a y

W MacArthur Blvd

MacArthur FwyEBMUD Water Treatment

Oakland Global Trade &

Logistics Center

Oakland Medical Center

P o s e y T u b e

11th St

16th St

W e b s te r S t

4th St th

A ve

17th St

24th St

24th St

13th St

W es t S t

W e s t S t

8th St

10th St

10th St

26th St W oo d S t

18th St

28th St

L in d e n S t

32nd St

U n io n S t

M y rt le

S t

30th St

C e n te r S t

Main St

34t h St

3rd St

B ru sh

S t

10th St

5th St

7th St

7th St

27th St

M a rk e t S t

M a rk e t S t

C a s tr o S t

A d e li n e S t

W Grand Ave

P er al ta

S t

17th St

T e le g ra p h A v e

Grand Ave

8th St

B ro a d w ay

B ro a d w ay

Nimitz Fwy

G ro ve

Sh af te r Fw y

Charles P.

Howard Terminal

Roundhouse Property

Jack London Square

South Prescott Park

Lakeside Park

West Oakland

Oakland th

S t

Buena Vista Ave

Atl antic Ave

O ri o n S t

Singleton Ave

F e rr y P t

V i k in g S t

M a in

S t

W e b s te r S t

W e b s te r S t

College of Alameda afem afem afem afem afem

Qbt

Qbt

Qds

Qds

Qf

Qhf

QofG le n Ec ho C re ek

San Rafael

San Francisco

San Leandro

Concord

Oakland

San Mateo Fremont

0 4,000 Feet

Scale: 1:24,000

Basemap Source: ESRI GEOLOGY MAP

Map Location

Exported: 12/19/2023

Legend

Geologic Data Source: Witter, et al. 2006. Maps of Quaternary Deposits and Liquefaction Susceptibility in the Central San Francisco Bay Region

Early to Late Pleistocene, alluvial fans

Pleistocene, Bay terrace deposits

Holocene to Latest Pleistocene, alluvial fans

Holocene to Latest Pleistocene, dune sand

Holocene, alluvials

Holocene, alluvial fans

Artificial fill over estuarine mud

Artificial fill

Qof

Qbt

Qf

Qds

Qha

Qhf afem af

PLATE NO.:

MARTIN LUTHER KING STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

JOB NO.: 2023-131-PAV

Project Site Martin Luther King Jr. Way (2nd Street to 12th Street)

APPENDIX A

LOGS OF TEST BORINGS

PAVEMENT CORE PHOTOS

MIDTOWN STATION

SAN JOAQUIN REGIONAL RAIL COMMISSION

SACRAMENTO, CALIFORNIA

A-1-A Project No. 2021-149-MTS

A-1-B

2023-131-PAV

ASPHALT CONCRETE (5").

CONCRETE (7").

Poorly graded SAND (SP); gray; moist; medium SAND; trace angular to subangular fine gravel (Fill/Base).

SILTY SAND (SM); medium dense; dark brown; moist;

medium SAND (Native Soil).

Dark yellowish brown; fine SAND; uncemented.

SILTY SAND (SM); medium dense; olive brown; wet;

fine to medium SAND; trace CLAY.

CLAYEY SAND (SC); medium dense; brownish yellow; moist; fine SAND.

Bottom of borehole at 15.0 ft bgs/Elev. -2.0 ft

Boring terminated at a depth of 15.0 ft.

Groundwater not encountered during drilling.

This Boring Record was developed in accordance with the Caltrans Soil & Rock Logging, Classification, and Presentation Manual (2022) except as noted on the Soil or Rock Legend or below.

R

SPT HAMMER TYPE

140 lb Auto Hammer with 30'' drop

DRILL RIG

Truck Mounted Mobile B-53

BOREHOLE BACKFILL AND COMPLETION

Borehole backfilled with cement grout.

DRILLING CONTRACTOR

EGS

LOGGED BY

Ocean

BEGIN DATE

10-31-23

COMPLETION DATE

10-31-23

TOTAL DEPTH OF BORING

15.0 ft

BOREHOLE DIAMETER

5 in

BOREHOLE LOCATION (Offset, Station, Line)

SAMPLER TYPE(S) AND SIZE(S) ID

SPT (1.4" ID)

AFTER DRILLING (DATE)

SURFACE ELEVATION

13.0 ft

DRILLING METHOD

Solid-Stem Auger

GROUNDWATER

READINGS

BOREHOLE LOCATION (Lat/Long or North/East and Datum)

37° 47' 53.8686" / -122° 16' 51.6282"

HOLE ID

B-1

DURING DRILLING

HAMMER EFFICIENCY, ERi

95%

A1-1

D ril lin g

M et ho d

R Q

D

R ec ov er y

M oi st ur e C on te nt

D ry

U ni t W ei gh t

(p cf

Job No.: 2023-131-PAV

S am pl e

D ep th

S am pl e

N um be r

E

LE

V A

T

IO

N ft)

11.00

9.00

7.00

5.00

3.00

1.00

-1.00

-3.00

-5.00

D E

P T

H ft)

DESCRIPTION

U C

/U U in S he ar

. S tr

(t sf

LOG OF TEST BORING

Date: 12/15/2023 Boring ID: B-1

Remarks

B lo w s pe r in

M at er ia l G ra ph ic s

B lo w s pe r fo ot

C as in g

D ep th

Plate:This log is part of the report prepared by Parikh Consultants, Inc. for the named project and should be read together with that report for complete interpretation. This summary applies only at the location of this boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.

MLK STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

P C

I- C

T

B R

3-

1- P

A V

.G P

J T

E M

P

LA

T E

-2

2-

.G D

T

1/ 3/

ASPHALT CONCRETE (10").

AGGREGATE BASE.

Poorly graded SAND with GRAVEL (SP); brown;

moist; fine SAND; trace cobbles (Fill/Base).

SILTY SAND (SM); medium dense; dark brown; moist;

fine SAND; uncemented (Native Soil).

Loose; brown; fine SAND.

Very loose; wet.

Medium dense; yellowish brown.

Bottom of borehole at 15.0 ft bgs/Elev. 0.0 ft

Boring terminated at a depth of 15.0 ft.

Groundwater encountered at a depth of 10.9' during drilling.

This Boring Record was developed in accordance with the Caltrans Soil & Rock Logging, Classification, and Presentation Manual (2022) except as noted on the Soil or Rock Legend or below.

PA

SPT HAMMER TYPE

140 lb Auto Hammer with 30'' drop

DRILL RIG

Truck Mounted Mobile B-53

BOREHOLE BACKFILL AND COMPLETION

Borehole backfilled with cement grout.

DRILLING CONTRACTOR

EGS

LOGGED BY

Ocean

BEGIN DATE

10-31-23

COMPLETION DATE

10-31-23

TOTAL DEPTH OF BORING

15.0 ft

BOREHOLE DIAMETER

5 in

BOREHOLE LOCATION (Offset, Station, Line)

SAMPLER TYPE(S) AND SIZE(S) ID

SPT (1.4" ID)

AFTER DRILLING (DATE)

SURFACE ELEVATION

15.0 ft

DRILLING METHOD

Solid-Stem Auger

GROUNDWATER

READINGS

BOREHOLE LOCATION (Lat/Long or North/East and Datum)

37° 47' 56.7738" / -122° 16' 49.2846"

HOLE ID

B-2

DURING DRILLING

10.9 ft

HAMMER EFFICIENCY, ERi

95%

A1-2

D ril lin g

M et ho d

R Q

D

R ec ov er y

M oi st ur e C on te nt

D ry

U ni t W ei gh t

(p cf

Job No.: 2023-131-PAV

S am pl e

D ep th

S am pl e

N um be r

E

LE

V A

T

IO

N ft)

13.00

11.00

9.00

7.00

5.00

3.00

1.00

-1.00

-3.00

D E

P T

H ft)

DESCRIPTION

U C

/U U in S he ar

. S tr

(t sf

LOG OF TEST BORING

Date: 12/15/2023 Boring ID: B-2

Remarks

B lo w s pe r in

M at er ia l G ra ph ic s

B lo w s pe r fo ot

C as in g

D ep th

Plate:This log is part of the report prepared by Parikh Consultants, Inc. for the named project and should be read together with that report for complete interpretation. This summary applies only at the location of this boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.

MLK STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

P C

I- C

T

B R

3-

1- P

A V

.G P

J T

E M

P

LA

T E

-2

2-

.G

ASPHALT CONCRETE (9").

Poorly graded GRAVEL (GP); gray; moist; angular to subangular gravel; trace SAND (Fill/Base).

SILTY SAND (SM); loose; dark yellowish brown;

moist; medium to coarse SAND; trace gravel (Fill).

SILTY SAND (SM); medium dense; dark yellowish brown; wet; fine to medium SAND (Native Soil).

Bottom of borehole at 15.0 ft bgs/Elev. 10.0 ft

Boring terminated at a depth of 15.0 ft.

Groundwater not encountered during drilling.

This Boring Record was developed in accordance with the Caltrans Soil & Rock Logging, Classification, and Presentation Manual (2022) except as noted on the Soil or Rock Legend or below.

R

SPT HAMMER TYPE

140 lb Auto Hammer with 30'' drop

DRILL RIG

Truck Mounted Mobile B-53

BOREHOLE BACKFILL AND COMPLETION

Borehole backfilled with cement grout.

DRILLING CONTRACTOR

EGS

LOGGED BY

Ocean

BEGIN DATE

11-1-23

COMPLETION DATE

11-1-23

TOTAL DEPTH OF BORING

15.0 ft

BOREHOLE DIAMETER

5 in

BOREHOLE LOCATION (Offset, Station, Line)

SAMPLER TYPE(S) AND SIZE(S) ID

SPT (1.4" ID)

AFTER DRILLING (DATE)

SURFACE ELEVATION

25.0 ft

DRILLING METHOD

Solid-Stem Auger

GROUNDWATER

READINGS

BOREHOLE LOCATION (Lat/Long or North/East and Datum)

37° 48' 3.6324" / -122° 16' 45.393"

HOLE ID

B-3

DURING DRILLING

HAMMER EFFICIENCY, ERi

95%

A1-3

D ril lin g

M et ho d

R Q

D

R ec ov er y

M oi st ur e C on te nt

D ry

U ni t W ei gh t

(p cf

Job No.: 2023-131-PAV

S am pl e

D ep th

S am pl e

N um be r

E

LE

V A

T

IO

N ft)

23.00

21.00

19.00

17.00

15.00

13.00

11.00

9.00

7.00

D E

P T

H ft)

DESCRIPTION

U C

/U U in S he ar

. S tr

(t sf

LOG OF TEST BORING

Date: 12/15/2023 Boring ID: B-3

Remarks

B lo w s pe r in

M at er ia l G ra ph ic s

B lo w s pe r fo ot

C as in g

D ep th

Plate:This log is part of the report prepared by Parikh Consultants, Inc. for the named project and should be read together with that report for complete interpretation. This summary applies only at the location of this boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.

MLK STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

P C

I- C

T

B R

3-

1- P

A V

.G P

J T

E M

P

LA

T E

-2

2-

.G

ASPHALT CONCRETE (6").

CONCRETE (7").

Poorly graded GRAVEL with SAND (GP); yellowish brown; moist; medium to coarse SAND; angular to subangular fine to coarse gravel (1.5" max) (Fill/Base).

SILTY SAND (SM); loose; brown; moist; fine SAND (Native Soil).

Very loose; dark yellowish brown.

Bottom of borehole at 15.0 ft bgs/Elev. 17.0 ft

Boring terminated at a depth of 15.0 ft.

Groundwater not encountered during drilling.

This Boring Record was developed in accordance with the Caltrans Soil & Rock Logging, Classification, and Presentation Manual (2022) except as noted on the Soil or Rock Legend or below.

PA

SPT HAMMER TYPE

140 lb Auto Hammer with 30'' drop

DRILL RIG

Truck Mounted Mobile B-53

BOREHOLE BACKFILL AND COMPLETION

Borehole backfilled with cement grout.

DRILLING CONTRACTOR

EGS

LOGGED BY

Ocean

BEGIN DATE

10-31-23

COMPLETION DATE

10-31-23

TOTAL DEPTH OF BORING

15.0 ft

BOREHOLE DIAMETER

5 in

BOREHOLE LOCATION (Offset, Station, Line)

SAMPLER TYPE(S) AND SIZE(S) ID

SPT (1.4" ID)

AFTER DRILLING (DATE)

SURFACE ELEVATION

32.0 ft

DRILLING METHOD

Solid-Stem Auger

GROUNDWATER

READINGS

BOREHOLE LOCATION (Lat/Long or North/East and Datum)

37° 48' 6.5484" / -122° 16' 43.2192"

HOLE ID

B-4

DURING DRILLING

HAMMER EFFICIENCY, ERi

95%

A1-4

D ril lin g

M et ho d

R Q

D

R ec ov er y

M oi st ur e C on te nt

D ry

U ni t W ei gh t

(p cf

Job No.: 2023-131-PAV

S am pl e

D ep th

S am pl e

N um be r

E

LE

V A

T

IO

N ft)

30.00

28.00

26.00

24.00

22.00

20.00

18.00

16.00

14.00

D E

P T

H ft)

DESCRIPTION

U C

/U U in S he ar

. S tr

(t sf

LOG OF TEST BORING

Date: 12/15/2023 Boring ID: B-4

Remarks

B lo w s pe r in

M at er ia l G ra ph ic s

B lo w s pe r fo ot

C as in g

D ep th

Plate:This log is part of the report prepared by Parikh Consultants, Inc. for the named project and should be read together with that report for complete interpretation. This summary applies only at the location of this boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.

MLK STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

P C

I- C

T

B R

3-

1- P

A V

.G P

J T

E M

P

LA

T E

-2

2-

.G

ASPHALT CONCRETE (5").

CONCRETE (7").

Poorly graded SAND with GRAVEL (SP); dark brown;

moist; angular gravel (9") (Fill/Base).

CLAYEY SAND (SC); very loose; dark yellowish brown; moist; medium SAND (Native Soil).

SILTY SAND (SM); very loose; dark yellowish brown;

moist; fine SAND.

Medium dense.

Bottom of borehole at 10.0 ft bgs/Elev. 27.0 ft

Boring terminated at a depth of 10.0 ft.

Groundwater not encountered during drilling.

This Boring Record was developed in accordance with the Caltrans Soil & Rock Logging, Classification, and Presentation Manual (2022) except as noted on the Soil or Rock Legend or below.

R

SPT HAMMER TYPE

140 lb Auto Hammer with 30'' drop

DRILL RIG

Truck Mounted Mobile B-53

BOREHOLE BACKFILL AND COMPLETION

Borehole backfilled with cement grout.

DRILLING CONTRACTOR

EGS

LOGGED BY

Ocean

BEGIN DATE

11-1-23

COMPLETION DATE

11-1-23

TOTAL DEPTH OF BORING

10.0 ft

BOREHOLE DIAMETER

5 in

BOREHOLE LOCATION (Offset, Station, Line)

SAMPLER TYPE(S) AND SIZE(S) ID

SPT (1.4" ID)

AFTER DRILLING (DATE)

SURFACE ELEVATION

37.0 ft

DRILLING METHOD

Solid-Stem Auger

GROUNDWATER

READINGS

BOREHOLE LOCATION (Lat/Long or North/East and Datum)

37° 48' 13.1868" / -122° 16' 39.3276"

HOLE ID

B-5

DURING DRILLING

HAMMER EFFICIENCY, ERi

95%

A1-5

D ril lin g

M et ho d

R Q

D

R ec ov er y

M oi st ur e C on te nt

D ry

U ni t W ei gh t

(p cf

Job No.: 2023-131-PAV

S am pl e

D ep th

S am pl e

N um be r

E

LE

V A

T

IO

N ft)

35.00

33.00

31.00

29.00

27.00

25.00

23.00

21.00

19.00

D E

P T

H ft)

DESCRIPTION

U C

/U U in S he ar

. S tr

(t sf

LOG OF TEST BORING

Date: 12/15/2023 Boring ID: B-5

Remarks

B lo w s pe r in

M at er ia l G ra ph ic s

B lo w s pe r fo ot

C as in g

D ep th

Plate:This log is part of the report prepared by Parikh Consultants, Inc. for the named project and should be read together with that report for complete interpretation. This summary applies only at the location of this boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.

MLK STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

P C

I- C

T

B R

3-

1- P

A V

.G P

J T

E M

P

LA

T E

-2

2-

.G

3a

3b

ASPHALT CONCRETE (5").

CONCRETE (6").

AGGREGATE BASE (2") (Fill).

Poorly graded SAND (SP); loose; yellowish brown;

moist; medium to fine SAND (Native Soil).

SILTY SAND (SM); loose; dark yellowish brown;

moist; fine SAND.

SANDY lean CLAY (CL); soft; dark yellowish brown;

moist; medium plasticity fines.

SILTY SAND (SM); medium dense; yellowish brown;

moist; fine SAND.

Bottom of borehole at 10.0 ft bgs/Elev. 29.0 ft

Boring terminated at a depth of 10.0 ft.

Groundwater not encountered during drilling.

This Boring Record was developed in accordance with the Caltrans Soil & Rock Logging, Classification, and Presentation Manual (2022) except as noted on the Soil or Rock Legend or below.

PA

SPT HAMMER TYPE

140 lb Auto Hammer with 30'' drop

DRILL RIG

Truck Mounted Mobile B-53

BOREHOLE BACKFILL AND COMPLETION

Borehole backfilled with cement grout.

DRILLING CONTRACTOR

EGS

LOGGED BY

Ocean

BEGIN DATE

11-1-23

COMPLETION DATE

11-1-23

TOTAL DEPTH OF BORING

10.0 ft

BOREHOLE DIAMETER

5 in

BOREHOLE LOCATION (Offset, Station, Line)

SAMPLER TYPE(S) AND SIZE(S) ID

SPT (1.4" ID)

AFTER DRILLING (DATE)

SURFACE ELEVATION

39.0 ft

DRILLING METHOD

Solid-Stem Auger

GROUNDWATER

READINGS

BOREHOLE LOCATION (Lat/Long or North/East and Datum)

37° 48' 16.743" / -122° 16' 37.1094"

HOLE ID

B-6

DURING DRILLING

HAMMER EFFICIENCY, ERi

95%

A1-6

D ril lin g

M et ho d

R Q

D

R ec ov er y

M oi st ur e C on te nt

D ry

U ni t W ei gh t

(p cf

Job No.: 2023-131-PAV

S am pl e

D ep th

S am pl e

N um be r

E

LE

V A

T

IO

N ft)

37.00

35.00

33.00

31.00

29.00

27.00

25.00

23.00

21.00

D E

P T

H ft)

DESCRIPTION

U C

/U U in S he ar

. S tr

(t sf

LOG OF TEST BORING

Date: 12/15/2023 Boring ID: B-6

Remarks

B lo w s pe r in

M at er ia l G ra ph ic s

B lo w s pe r fo ot

C as in g

D ep th

Plate:This log is part of the report prepared by Parikh Consultants, Inc. for the named project and should be read together with that report for complete interpretation. This summary applies only at the location of this boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.

MLK STREETSCAPE PROJECT

OAKLAND, CALIFORNIA

P C

I- C

T

B R

3-

1- P

A V

.G P

J T

E M

P

LA

T E

-2

2-

.G

PROJECT NO.: 2023-131-PAV PLATE NO.: A-2-1

OAKLAND, CALIFORNIA

B-2B-1

B-3 B-4

PROJECT NO.: 2023-131-PAV PLATE NO.: A-2-2

B-6B-5

APPENDIX B

LABORATORY TEST RESULTS

B-1 1 1.2 - - - B-1 2 2.7 - - - B-1 3 5.0 - 9.1 - B-1 4 8.5 - 16.7 - B-1 5 13.0 - 16.9 - B-2 2 1.0 - - - B-2 1 2.1 - - - B-2 3 5.0 - 9.5 - 8.4 19.2 B-2 4 8.5 - 17.2 - B-2 5 13.5 - 19.9 - B-3 1 2.1 - - - B-3 2 3.6 - - - B-3 3 5.0 - 22.6 - B-3 4 8.5 - - - B-4 1 2.5 - - - B-4 2 4.0 - - - B-4 3 5.0 - 13.8 - 0.3 22.0 B-4 4 8.5 - - - B-5 1 1.8 - - - B-5 2 3.3 - - - B-5 3 5.0 - 14.7 - B-5 4 8.5 - 13.4 - B-6 3 5.0 - - - B-6 3a 5.0 - 14.2 - 21.6 B-6 3b 6.0 - 22.2 - B-6 4 8.5 - 12.6 -

Sieve 200

Sieve 4

Plasticity Index

Plastic Limit

Water Content

Classi-ficationDepth Liquid

Limit Dry

Density Sample NumberBorehole

Shear Strength

(tsf)

JOB NO: 2023-131-PAV PLATE NO: III-2

MLK STREETSCAPE PROJECT

APPENDIX C

STRUCTURAL PAVEMENT

SECTION CALCULATIONS

PAVEMENT DESIGN

PER HIGHWAY DESIGN MANUAL, CHAP. 600

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: Full depth AC

Design TI= 8.5

RBS= 40

GE AC = 0.0032*TI*(100-R BS ) = 1.63

=> GE'AC= 1.73 (add 0.1 ft safety factor)

=> AC Thickness= 0.78

=> AC Thickness= 0.80 ft (round up to the nearest 0.05 ft)

Design Section:

0.80 ft

Base Soil

AC

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: AC over AB

Design TI= 8.5

RBS= 40

RAB= 78

GE AC+AB = 0.0032*TI*(100-R BS ) = 1.63

GE AC = 0.0032*TI*(100-R AB ) = 0.60

=> GE'AC = 0.80 (add 0.2 ft safety factor)

AC Thickness = 0.41 ft

=> AC Thickness = 0.45 ft (round up to the nearest 0.05 ft)

Gf, AC = 1.94

GEAC = 0.88

GE AB = GE AC+AB - GE AC = 0.76

AB thickness= 0.69 ft

=> AB Thickness= 0.70 ft (round up to the nearest 0.05 ft)

GEAB= 0.77 Gf, AB=1.1

Design Section:

ft ft

AC

Base Soil

AB

0.45

0.70

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: Full depth AC

Design TI= 9

RBS= 40

GE AC = 0.0032*TI*(100-R BS ) = 1.73

=> GE'AC= 1.83 (add 0.1 ft safety factor)

=> AC Thickness= 0.83

=> AC Thickness= 0.85 ft (round up to the nearest 0.05 ft)

Design Section:

0.85 ft

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: AC over AB

Design TI= 9

RBS= 40

RAB= 78

GE AC+AB = 0.0032*TI*(100-R BS ) = 1.73

GE AC = 0.0032*TI*(100-R AB ) = 0.63

=> GE'AC = 0.83 (add 0.2 ft safety factor)

AC Thickness = 0.44 ft

=> AC Thickness = 0.45 ft (round up to the nearest 0.05 ft)

Gf, AC = 1.89

GEAC = 0.85

GE AB = GE AC+AB - GE AC = 0.88

AB thickness= 0.80 ft

=> AB Thickness= 0.80 ft (round up to the nearest 0.05 ft)

GEAB= 0.88 Gf, AB=1.1

Design Section:

ft ft

AC

Base Soil

AB

0.45

0.80

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: Full depth AC

Design TI= 9.5

RBS= 40

GE AC = 0.0032*TI*(100-R BS ) = 1.82

=> GE'AC= 1.92 (add 0.1 ft safety factor)

=> AC Thickness= 0.88

=> AC Thickness= 0.90 ft (round up to the nearest 0.05 ft)

Design Section:

0.90 ft

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: AC over AB

Design TI= 9.5

RBS= 40

RAB= 78

GE AC+AB = 0.0032*TI*(100-R BS ) = 1.82

GE AC = 0.0032*TI*(100-R AB ) = 0.67

=> GE'AC = 0.87 (add 0.2 ft safety factor)

AC Thickness = 0.47 ft

=> AC Thickness = 0.50 ft (round up to the nearest 0.05 ft)

Gf, AC = 1.84

GEAC = 0.92

GE AB = GE AC+AB - GE AC = 0.90

AB thickness= 0.82 ft

=> AB Thickness= 0.85 ft (round up to the nearest 0.05 ft)

GEAB= 0.94 Gf, AB=1.1

Design Section:

ft ft

AC

Base Soil

AB

0.50

0.85

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: Full depth AC

Design TI= 11.5

RBS= 40

GE AC = 0.0032*TI*(100-R BS ) = 2.21

=> GE'AC= 2.31 (add 0.1 ft safety factor)

=> AC Thickness= 1.09

=> AC Thickness= 1.10 ft (round up to the nearest 0.05 ft)

Design Section:

1.10 ft

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: AC over AB

Design TI= 11.5

RBS= 40

RAB= 78

GE AC+AB = 0.0032*TI*(100-R BS ) = 2.21

GE AC = 0.0032*TI*(100-R AB ) = 0.81

=> GE'AC = 1.01 (add 0.2 ft safety factor)

AC Thickness = 0.58 ft

=> AC Thickness = 0.60 ft (round up to the nearest 0.05 ft)

Gf, AC = 1.74

GEAC = 1.04

GE AB = GE AC+AB - GE AC = 1.16

AB thickness= 1.06 ft

=> AB Thickness= 1.10 ft (round up to the nearest 0.05 ft)

GEAB= 1.21 Gf, AB=1.1

Design Section:

ft ft

AC

Base Soil

AB

0.60

1.10

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: Full depth AC

Design TI= 12

RBS= 40

GE AC = 0.0032*TI*(100-R BS ) = 2.30

=> GE'AC= 2.40 (add 0.1 ft safety factor)

=> AC Thickness= 1.14

=> AC Thickness= 1.15 ft (round up to the nearest 0.05 ft)

Design Section:

1.15 ft

PROJECT NAME: MLK Streetscape Project

PROJECT NO.: 2023-131-PAV

Design Case: AC over AB

Design TI= 12

RBS= 40

RAB= 78

GE AC+AB = 0.0032*TI*(100-R BS ) = 2.30

GE AC = 0.0032*TI*(100-R AB ) = 0.84

=> GE'AC = 1.04 (add 0.2 ft safety factor)

AC Thickness = 0.61 ft

=> AC Thickness = 0.65 ft (round up to the nearest 0.05 ft)

Gf, AC = 1.75

GEAC = 1.14

GE AB = GE AC+AB - GE AC = 1.17

AB thickness= 1.06 ft

=> AB Thickness= 1.10 ft (round up to the nearest 0.05 ft)

GEAB= 1.21 Gf, AB=1.1

Design Section:

ft ft

AC

Base Soil

AB

0.65

1.10

Table 1. Calculated Martin Luther King Jr Way Traffic Index (TI) Values

Roadway Segment Direction

Calculated Traffic Index (TI) Value

-Y e ar T

I

-Y e ar T

I

-Y e ar T

I

-Y e ar T

I

Martin Luther King Jr Way

Between Embarcadero West and 2nd Street Northbound 10.0 11.0 11.5 12.0

Southbound 10.5 11.0 11.5 12.0

Between 2nd Street and 3rd Street Northbound 10.5 11.0 12.0 12.0

Southbound 10.5 11.0 11.5 12.0

Between 3rd Street and 4th Street Northbound 9.5 10.5 11.0 11.5

Southbound 8.0 8.5 9.0 9.5

Between 4th Street and 5th Street Northbound 9.5 10.5 11.0 11.5

Southbound 8.0 8.5 9.0 9.5

Between 5th Street and 6th Street Northbound 8.0 8.5 9.0 9.5

Southbound 7.0 7.5 8.0 8.0

Between 6th Street and 7th Street Northbound 7.5 8.0 8.5 9.0

Southbound 7.5 8.0 8.5 8.5

Between 7th Street and 8th Street Northbound 7.5 8.0 8.5 8.5

Southbound 7.0 7.5 8.0 8.5

Between 8th Street and 9th Street Northbound 7.5 8.0 8.5 9.0

Southbound 7.0 8.0 8.0 8.5

Between 9th Street and 10th Street Northbound 7.5 8.0 8.5 8.5

Southbound 7.5 8.0 8.5 8.5

Between 10th Street and 11th Street Northbound 7.5 8.0 8.5 8.5

Southbound 7.5 8.0 8.5 8.5

Between 11th Street and 12th Street Northbound 7.5 8.0 8.5 8.5

Southbound 7.5 8.0 8.5 8.5

Between 12th Street and 13th Street Northbound 7.5 8.0 8.5 9.0

Southbound 7.5 8.0 8.5 9.0

Between 13th Street and 14th Street Northbound 7.5 8.0 8.0 8.5

Southbound 7.5 8.0 8.5 9.0

11th Street

Between Brush Street/I-980 SB On-Ramp and Castro Street/I-980 EB Off-Ramp

Eastbound 7.0 8.0 8.0 8.5

Westbound -- -- -- --

Between Castro Street/I-980 EB Off-Ramp and Martin Luther King Jr Way (4 lanes)

Eastbound 7.5 8.5 8.5 9.0

Westbound -- -- -- --

Between Castro Street/I-980 EB Off-Ramp and Martin Luther King Jr Way (2 lanes)1

Eastbound 8.5 9.0 9.5 9.5

Westbound -- -- -- --

Between Martin Luther King Jr Way and Jefferson Street

Eastbound 7.5 8.5 9.0 9.0

Westbound -- -- -- --

12th Street Between Brush Street/I-980 SB Off-Ramp and Castro Street/I-980 EB On-Ramp

Eastbound -- -- -- --

Westbound 7.0 8.0 8.0 8.5 1 TI values were calculated at 11th Street between Castro Street and Martin Luther King Jr Way for both Project conditions and improved Project conditions

TRAFFIC INDEX INFORMATION PROVIDED BY DESIGNER

Appendix D Structural Pavement Section Calculations

BASELINE ENVIRONMENTAL REPORTBaseline Environmental Consulting - Limited Soil Investigation Report

388 17th Street, Suite 230, Oakland, CA 94612 | (510) 420-8686 | www.baseline-env.com Mailing Address: PO Box 18586, Oakland, CA 94619

January 6, 2024 23311‐00

David Wang PARIKH Consultants Inc.

1497 N. Milpitas Blvd.

Milpitas, CA 95035

Subject: Limited Soil Investigation Report for the Martin Luther King Streetscape Project, Oakland, California

Dear Mr. Wang:

Baseline has prepared this Limited Soil Investigation Report for the Martin Luther King Streetscape Project (project) in the City of Oakland, California. The project extends along Martin Luther King Jr. Way from 2nd Street to 14th Street and will enhance connectivity between West Oakland, Old Oakland, Jack London District, and the waterfront. The proposed project will include bike lane, crosswalk, pavement, curb, gutter, sidewalk, and drainage improvements, as well as installation of streetlight and signal foundations and raised medians with planter strips for trees. The design plans for the proposed project improvements are still being developed, but it is expected that there may be relatively minor soil disturbance throughout the project site with some areas of deeper soil excavation and disposal required to support tree plantings and pole foundations. The purpose of this investigation was to evaluate potential soil contamination beneath areas of proposed project improvements for potential offsite disposal and to support worker health and safety protocols.

SAMPLING ACTIVITIES

On October 31 and November 1, 2023, soil sampling activities were performed by PARIKH Consulting Inc. during the drilling of six geotechnical borings (B‐1 through B‐6) in areas of the proposed project improvements. Soil samples were collected from a depth of approximately 1 foot below the road base material in borings B‐1 through B‐6 along Martin Luther King Jr. Way (Figure 1). The soil samples were collected in stainless steel liners from the desired depth. The samples were sealed, labeled with a project name, date and time of sample collection, and unique sample identification, and placed in a cooler containing ice, and delivered to Enthalpy Analytical, a State‐certified analytical laboratory.

Mr. David Wang

LABORATORY ANALYSIS

Laboratory analysis of the six soil samples included Title 22 Metals by Environmental Protection Agency (EPA) Method 6010B/7471A; total petroleum hydrocarbons as gasoline (TPH‐g), diesel (TPH‐d), and motor oil (TPH‐mo) by EPA Methods 8015B and 8015M; and volatile organic compounds (VOCs) by EPA Method 8260B. Based on elevated total lead concentrations reported in the soil sample from boring B‐3 (see discussion below), soluble lead analysis was performed in accordance with the Waste Extraction Test (WET) method and the Toxicity Characteristic Leaching Procedure (TCLP) method. A copy of the laboratory analytical report is included in Appendix A.

ANALYTICAL RESULTS

As summarized in Table 1, the soil analytical results for Title 22 metals were compared to the San Francisco Bay Regional Water Quality Control Board’s (Regional Water Board’s) Environmental Screening Levels (ESLs) for construction worker direct exposure,1 California hazardous waste criteria, and federal hazardous waste criteria. Concentrations of metals were below the construction worker ESLs and hazardous waste criteria in all soil samples, except the soil sample from boring B‐3. In boring B‐3, the total lead concentration (570 milligrams per kilogram [mg/kg]) exceeded the construction worker ESL of 160 mg/kg and the WET lead concentration (8.9 milligrams per liter [mg/L]) exceeded the California hazardous waste criterion of 5.0 mg/L. The TCLP lead concentration in boring B‐3 was below the federal hazardous waste criterion. All other metal concentrations reported in the soil sample from boring B‐3 were below the construction worker ESLs and hazardous waste criteria.

As summarized in Table 2, the soil analytical results for TPH‐g, TPH‐d, TPH‐mo, and VOCs were all below laboratory reporting limits and construction worker ESLs. Furthermore, no apparent staining or odors that could potentially indicate soil contamination were observed in the field.

CONCLUSIONS AND RECOMMENDATIONS

Based on the soil analytical results, the shallow soils in the vicinity of borings B‐1, B‐2, B‐4, B‐5, and B‐6 would be classified as non‐hazardous waste for disposal purposes and would not pose a potential health risk to construction workers. The shallow soils in the vicinity of boring B‐3 would be classified as a non‐RCRA California hazardous waste for disposal purposes and could pose a potential health risk to construction workers due to the elevated lead concentrations found in boring B‐3.

The vertical and horizontal extent of shallow soil impacted by lead contamination in the vicinity of boring B‐3 has not been defined; therefore, it should be assumed that all soils excavated

1 Regional Water Board, 2019. Environmental Screening Levels, January.

Mr. David Wang between borings B‐2 to B‐4 should be disposed of as a non‐RCRA California hazardous waste based on the current data. Based on the final project design, additional soil sampling in areas of proposed excavation near boring B‐3 to characterize the extent of contamination may help reduce soil disposal costs. The project contractor(s) should also incorporate the soil analytical results from this memorandum into their health and safety plan to ensure appropriate personal protective equipment and soil management procedures (e.g., dust control) are applied.

Sincerely, William Scott, PG No. 6104 Johnathan Rizzo‐Mosbaugh Senior Field Geologist Staff Environmental Scientist

FIGURE

23311-00 Figures /03/2401

Figure 1 LocationsBoring

Martin Luther King Streetscape Project

NN

00 700 Feet700 Feet

Legend

Soil Sampling Locations

TABLES

Table 1: Soil Analytical Results for Title 22 Metals

Sample ID Sample Date A n ti m o n y

A rs en ic

B a ri u m

B er yl li u m

C a d m iu m

C h ro m iu m

C o b a lt

C o p p er

Le a d

W

ET

L ea d

TC

LP

L ea d

M e rc u ry

M o ly b d en u m

N ic ke l

Se le n iu m

Si lv er

Th al li u m

V an ad iu m

Zi n c

Units: mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/L mg/L mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg 500 500 10,000 75 100 2,500 8,000 2,500 1,000 NV NV 20 3,500 2,000 100 500 700 2,400 5,000

NV NV NV NV NV NV NV NV NV 5.0 NV NV NV NV NV NV NV NV NV

NV NV NV NV NV NV NV NV NV NV 5.0 NV NV NV NV NV NV NV NV

50 11 1 3,000 27 51 530,000 27.9 14,000 160 NV NV 44 1,800 86 1,700 1,800 3.5 470 110,000

B‐1;00.0‐01.0 10/31/2023 <2.9 1.6 69 <0.48 <0.48 31 5.7 6.7 6.6 ‐‐ ‐‐ <0.16 <0.96 21 <2.9 <0.48 <2.9 22 22 B‐2;00.0‐01.0 10/31/2023 <2.9 1.6 54 <0.48 <0.48 38 5.5 8.0 9.3 ‐‐ ‐‐ <0.14 <0.95 28 <2.9 <0.48 <2.9 28 25 B‐3;00.0‐01.0 11/1/2023 <2.9 1.8 48 <0.48 <0.48 33 5.9 6.9 570 8.9 0.19 <0.15 <0.96 21 <2.0 <0.48 <2.9 24 17 B‐4;00.0‐01.0 10/31/2023 <2.9 2.2 64 <0.49 <0.49 57 5.2 8.6 5.3 ‐‐ ‐‐ <0.15 <0.98 38 <2.9 <0.49 <2.9 32 25 B‐5;00.0‐01.0 11/1/2023 <2.9 2.3 64 <0.49 <0.49 52 5.7 8.1 3.5 ‐‐ ‐‐ <0.15 <0.97 38 <2.9 <0.49 <2.9 33 25 B‐6;00.0‐01.0 11/1/2023 <2.9 1.7 52 <0.49 <0.49 34 3.9 5.9 2.5 ‐‐ ‐‐ <0.15 <0.98 19 <2.9 <0.49 <2.9 24 15

Key:

<xx = indicates constituent was not identified at or above the laboratory reporting limit of xx

‐‐ = constituent not analyzed

Concentration equal to or greater than hazardous waste criterion

Concentration equal to or greater than Construction Worker ESL

Notes:

mg/kg = milligrams per kilogram; mg/L = milligrams per liter; NV = no value; ESL = Environmental Screening Level (Regional Board, 2019); TTLC = Total Threshold Limit Concentration; STLC = Soluble

Threshold Limit Concentration; Title 22 = the 17 inorganic compounds listed under Title 22 of the California Code of Regulations

Samples were analyzed for Title 22 metals in accordance with U.S. Environmental Protection Agency Methods 6010B and 7471A.

Bay Area was substituted for the construction worker ESL of 0.98 mg/kg.

Assumes the total chromium concentration is chromium III.

1 In accordance with guidance from Regional Water Board, the upper 99th percentile estimate of the naturally‐occurring background arsenic concentrations reported by Duvergé (2011) in the San Francisco

California TTLC California STLC

Federal TCLP Threshold Construction Worker ESL

23311‐00 Summary Table Page 1 of 1

Table 2: Soil Analytical Results for Total Petroleum Hydrocarbons and Volatile Organic Compounds

Sample ID

Sample Depth

(feet bgs) Sample Date

TPH‐g

(mg/kg)

TPH‐d

(mg/kg)

TPH‐mo

(mg/kg)

VOCs

(mg/kg)

NV NV NV NV

1,800 1,100 54,000 NV

B‐1;00.0‐01.0 00.0‐01.0 10/31/2023 <3.0 <9.9 <20 ND

B‐2;00.0‐01.0 00.0‐01.0 10/31/2023 <3.0 <10 <20 ND

B‐3;00.0‐01.0 00.0‐01.0 11/1/2023 <3.0 <10 <20 ND

B‐4;00.0‐01.0 00.0‐01.0 10/31/2023 <3.0 <10 <20 ND

B‐5;00.0‐01.0 00.0‐01.0 11/1/2023 <3.0 <10 <20 ND

B‐6;00.0‐01.0 00.0‐01.0 11/1/2023 <3.0 <9.9 <20 ND

Key:

<xx = indicates constituent was not identified at or above the laboratory reporting limit of xx

ND= Not detected

Concentration equal to or greater than the California hazardous waste criterion

Concentration equal to or greater than Construction Worker Environmental Screening Level

Notes:

bgs = below ground surface; mg/kg = milligrams per kilogram; NV = no value; TPH‐g = total petroleum hydrocarbons as gasoline;

TPH‐d = total petroleum hydrocarbons as diesel; TPH‐mo = total petroleum hydrocarbons as motor oil.

Samples were analyzed for total petroleum hydrocarbons by U.S. Environmental Protection Agency Method 8015.

California Total Threshold Limit Concentration

Construction Worker Environmental Screening Level

23311‐00 Summary Table Page 1 of 1