(excerpts from summary and first two sections)
This document may be found, in its entirety at:
http://www.dot.ca.gov/
FHWA-CA-EIS-98-01-D
04-SF-80 KP 12.2/KP 14.3
04-ALA-80 KP 0.0/KP 2.1
EA# 04-251-012000
SAN FRANCISCO - OAKLAND BAY BRIDGE
EAST SPAN SEISMIC SAFETY PROJECT
on Interstate 80 between
Yerba Buena Island and Oakland
in San Francisco and Alameda Counties
DRAFT ENVIRONMENTAL IMPACT STATEMENT/
Submitted pursuant to 42 USC 4332 (2)(c) and 49 USC 303
by the
US DEPARTMENT OF TRANSPORTATION FEDERAL HIGHWAY ADMINISTRATION
and
THE STATE OF CALIFORNIA DEPARTMENT OF TRANSPORTATION
In Cooperation with the
UNITED STATES COAST GUARD
HARRY YAHATA S/9/21/98
District Director
District 4
California Department of Transportation
JEFFREY A. LINDLEY S/9/21/98
Division Administrator
Federal Highway Administration
The following persons may be contacted for additional information concerning this document:
Brian Maroney, Project Manager
East Span Seismic Safety Project
Toll Bridge Program
Caltrans District 4
111 Grand Avenue
P.O. Box 23660
Oakland, CA 94623-0660
(510) 286-5885
John R. Schultz, Chief
District Operations North
Federal Highway Administration
980 Ninth Street, Suite 400
Sacramento, CA 95814-2724
(916) 498-5041
ABSTRACT: Caltrans proposes to ensure a lifeline vehicular connection between Yerba Buena Island in San Francisco and the SFOBB Toll Plaza in Oakland by seismic upgrading of the existing East Span. Alternatives include existing structure retrofit, two replacement alternatives north of the existing bridge, and one replacement alternative to the south. Three bridge main span design variations (cable stayed, self-anchored suspension, and skyway) are being considered. Long-term and temporary impacts include: potential displacement of Caltrans and USCG buildings; change in visual setting; noise; hazardous wastes; water quality; displacement of waters of the U.S. and special aquatic sites; disturbance of special status species habitat; and displacement of archaeological and historic resources. Proposed mitigation measures include: revegetation; consideration of soundwalls; removal of contaminated soils; in-kind replacement of special aquatic sites; treatment plans for archaeological resources; documentation of historic structures; and construction period traffic control measures and Best Management Practices.
Comments on this Draft ElS are due by November 9, 1998, and should be sent to: Mara Melandry, Caltrans District 4, 111 Grand Avenue (P.O. Box 23660), Oakland, California 94623-0660, (510) 286-5582 or by sending e-mail to sfobb.dist04@dot.ca.gov.
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[end DEIS 00]
PREFACE
This Draft Environmental Impact Statement (EIS) has been prepared pursuant to the requirements of the National Environmental Policy Act (NEPA) by the Federal Highway Administration (FHWA) and the California Department of Transportation (Caltrans), acting as joint lead agencies. The U.S. Coast Guard is a cooperating agency. It evaluates potential impacts of seismic retrofit and replacement alternatives proposed by Caltrans for improving the San Francisco-Oakland Bay Bridge (SFOBB) East Span in order to provide a seismically upgraded bridge over a portion of San Francisco Bay between Yerba Buena Island (YBI) in San Francisco and Oakland. This project is exempt by statute from the requirements of the California Environmental Quality Act (CEQA).
This project is one of several that Caltrans is undertaking to address the overall need to provide a lifeline bridge connection between the cities of San Francisco and Oakland. The other projects include replacing the West Approach in San Francisco, retrofitting the West Span, West YBI Viaduct, and YBI Tunnel, and the interim retrofit on the East Span.
This document is being circulated for a 45-day public review period, during which public hearings will be held on the project. Public and agency comments will be accepted orally and in writing at the public hearings and in writing until the close of the public review period on November 9, 1998. Following receipt and consideration of all public and agency comments on the Draft EIS, Caltrans and FHWA will identify a preferred alternative and a Final EIS will be prepared. The Final EIS will identify the preferred alternative, impacts and mitigation commitments, and will provide a written response to all comments received during the public comment period.
This Draft EIS describes the project purpose and need (Chapter 1), alternatives under consideration and alternatives considered and withdrawn (Chapter 2), affected environment (Chapter 3), project impacts by alternative, and proposed mitigation measures (Chapter 4). Chapter 5 explains the project’s exemption from the requirements of CEQA. Chapter 6 provides the Draft Section 4(f) Evaluation. Chapter 7 is an index of key words.
Appendices to this Draft EIS include figures and drawings referenced in the text (Appendix A); qualifications of preparers (Appendix B); a list of recipients of this document (Appendix C); and a glossary of terms and acronyms (Appendix D). Appendices E-G include documentation of consultation and correspondence. The CEQA Statutory Exemption form is in Appendix H. Appendix I is an explanation of relocation assistance provided to residents or businesses displaced by the project; a bibliography is in Appendix J. A description of rock motion anticipated in a seismic event is in Appendix K.
The impacts information presented herein is based upon the following technical studies that have been prepared for the project.
Air Quality Memorandum
Bicycle and Pedestrian Study
Biological Assessment
Community Impact Assessment
Extended Study Report, Archaeological
Resources
Finding of Adverse Effect: Built
Environment
Finding of Effect for Archaelogical
Resources
Hazardous Wastes Assessment
Historic Property Survey Report
Location Hydraulic Study
Natural Environment Study
Noise and Vibration Study
Draft Relocation Impact Report
Traffic Circulation, Access, and Parking
Assessment
Visual Impact Assessment
Alternatives addressed in this Draft EIS include replacement bridge alternatives defined through an extensive community involvement process led by the Metropolitan Transportation Commission (MTC). The MTC is a regional governmental agency that provides regional transportation planning and coordination of transportation activities for the nine-county Bay Area. The MTC functions as both the regional transportation planning agency (RTPA), a state designation, and for federal purposes under 23 CFR 134, as the region’s metropolitan planning organization (MPO). As such, the MTC is responsible for implementing the Regional Transportation Plan (RTP), which is a comprehensive blueprint for the development of mass transit, highway, airport, seaport, railroad, and bicycle and pedestrian facilities. Requests from local agencies for state and federal grants for transportation projects are screened by the MTC to determine their compatibility with the RTP. The MTC is also the Bay Area Toll Authority, under Section 30950 of the California Streets and Highway Code.
The MTC organized the San Francisco-Oakland Bay Bridge Design Task Force (Task Force) to consider replacement bridge alternatives following Governor Pete Wilson’s February 1997 decision that replacement alternatives should be considered. All the members of the Task Force are MTC Commissioners. The Task Force mandate was to develop a consensus recommendation on a design option for a new eastern span of the SFOBB and recommend any additional features that might be included in the design of the bridge that would not be borne by funding allocated from the State of California. The additional features would be paid by Bay Area bridge users through a toll surcharge at the state-owned toll bridges.
The MTC Task Force formed an Engineering and Design Advisory Panel (EDAP) to advise the Task Force on issues of cost, engineering feasibility, design factors, and seismic safety. The EDAP is comprised of technical experts in structural and civil engineering and architecture. EDAP deliberations included meetings and workshops open to the public for presentation of design concepts from interested parties. Beginning with the first of four formal public hearings on March 27, 1997, the Task Force has considered replacement bridge options (e.g., different types of replacement bridge structures) and the cost and feasibility of including design features such as "signature" bridge structures and a pedestrian/bicycle path.
The Task Force made its summary recommendations to Caltrans on July 30, 1997, concerning replacement bridge types, alignment, and a request for additional analysis needed to determine cost and feasibility of design components and features. Recommendations of the Task Force were transmitted to Caltrans and the State Legislature to assist in the determination of potential funding needs for the project.
In response to Task Force recommendations, Caltrans initiated the requested preliminary design studies. The 30 percent design studies were used to determine the seismic performance, cost, and aesthetics of the bridge types recommended for further study by the Task Force. The EDAP reviewed results of design studies in a series of public meetings and made specific recommendations to the Task Force (see Appendix E: Consultation and Coordination). On June 24, 1998, following extensive public comment, the Task Force forwarded an advisory recommendation to MTC that the replacement structure be a concrete skyway structure with an asymmetrical self-anchored suspension main span supported by a single steel tower. A 4.7-meter (15.5-foot) wide pedestrian/bicycle path 0.3 meter (one foot) higher than the traffic lanes located on the south side of the eastbound structure was also recommended and accepted by the MTC.
Alternative N-6, self-anchored suspension design variation, analyzed in this Draft EIS matches the bridge type recommendation defined through the Task Force proceedings. Although this alternative represents the bridge type recommendation of the MTC Task Force, it is not designated as a Recommended or Preferred Alternative in the Draft EIS. The Task Force recommendation is considered advisory and represents the locally preferred option. Caltrans and the FHWA have considered and performed preliminary engineering on a range of possible project alternatives in accordance with NEPA requirements and in consultation with permitting and regulatory agencies. Five alternatives (No-Build, Retrofit Existing Structure, two northern alignments, and one southern alignment) are currently under consideration for the East Span Project. Caltrans and the FHWA will identify a preferred alternative following circulation of this Draft EIS and consideration of public and agency comments on the document.
Copies of the Draft EIS and technical studies are available for public review at the following locations:
Caltrans Public Information Office
111 Grand Avenue
Oakland, CA 94612-3006
(510) 286-4444
Contra Costa County Library
1750 Oakpark Boulevard
Pleasant Hill, CA 94526
(925) 646-6434
Metropolitan Transportation Commission/Association of Bay Area Governments Library
101 Eighth Street
Oakland, CA 94607
(510) 464-7700
Oakland Main Library
125 14th Street
Oakland, CA 94612
(510) 238-3134
San Francisco Main Library
100 Larkin Street
San Francisco, CA 94102
(415) 557-4400
John F. Kennedy Library
505 Santa Clara Street
Vallejo, CA 94590
(707) 553-5568
Caltrans can be contacted by e-mail at sfobb.dist04@dot.ca.gov.
Click here to return to the Table of Contents
[end DEIS 01]
SUMMARY
The California Department of Transportation (Caltrans) proposes to retrofit or replace the San Francisco-Oakland Bay Bridge (SFOBB) East Span, which has carried vehicles between Yerba Buena Island (YBI) and Oakland since 1936. The East Span is a double-deck structure 3,696 meters (12,127 feet) in length carrying five traffic lanes in each direction, east- and westbound.
This Draft Environmental Impact Statement (EIS) has been prepared by Caltrans and the Federal Highway Administration (FHWA) pursuant to the National Environmental Policy Act (NEPA) to analyze potential environmental and socioeconomic impacts of several possible replacement bridge alternatives, as well as retrofit of the existing structure and no-build alternatives. The project is exempt by statute from the provisions of the California Environmental Quality Act (CEQA). The U.S. Coast Guard (USCG) is a cooperating agency.
S.1 PROJECT VICINITY AND PROJECT LIMITS
Alternatives analyzed in this Draft EIS would seismically retrofit or replace the East Span, involving construction activities and physical changes on both ends of the span and within the Bay. The west end of the project area is located west of the tunnel on YBI within the City and County of San Francisco (CCSF), and the east end of the project area is located in the City of Oakland, Alameda County. The project study area includes San Francisco Bay waters adjacent to the bridge in which construction activities might occur. In addition, Bay waters on the north side of YBI are included within the project area to allow staging for large construction equipment and bulk materials to be delivered to YBI by barge or vessel.
S.2 PURPOSE OF AND NEED FOR THE PROJECT
The SFOBB is an important part of the Bay Area as it provides regional access between the San Francisco Peninsula and the East Bay. Approximately 350,000 people in 274,000 vehicles currently use the bridge each day. As a component of Interstate 80 (I-80), it is also a critical link in the interstate network.
The purpose of the East Span Project is to provide a seismically upgraded vehicular crossing for current and future users between YBI and Oakland. This project is one of several that Caltrans is undertaking to address the overall need to provide a lifeline bridge connection on SFOBB between the cities of San Francisco and Oakland. The other projects include replacing the west approach in San Francisco, retrofitting the West Span, West YBI Viaduct, and YBI tunnel, and the interim retrofit on the East Span.
The existing East Span must be replaced or retrofitted because: it is not expected to withstand a maximum credible earthquake (MCE) on the San Andreas fault (an earthquake of magnitude 8 on the Richter scale) or Hayward fault (an earthquake of magnitude 7 1/4); it does not meet "lifeline" criteria for providing emergency relief access following an MCE; and, it does not meet current operations and safety design standards.
The Retrofit Existing Structure Alternative and the replacement alternatives would meet the project purpose and need to varying degrees. All replacement alternatives would fulfill the project purpose and address the need to provide a lifeline connection between the East Bay and Yerba Buena and Treasure Islands, to enable the East Span to withstand an MCE, and to satisfy current operational and safety standards. The Retrofit Existing Structure Alternative would retrofit the existing bridge to withstand an MCE, but the bridge would most likely experience substantial damage. The Retrofit Existing Structure Alternative would not permit changes to the existing bridge; therefore, current design standards could not be attained. The No-Build Alternative does not satisfy the project purpose and need.
Twelve alternatives, in addition to the No-Build Alternative, were considered during the scoping phase of this project. Four alternatives plus the No-Build Alternative were carried forward for the detailed analysis in this EIS, as described below. The project alternatives are shown on Figure S-1.
The No-Build Alternative would retain the existing SFOBB East Span. The No-Build Alternative assumes that the interim retrofitting of the East Span has been completed as a prior project. The Interim Retrofit Project is currently under way to strengthen bents and columns on the viaduct section on YBI and strengthen piers, bents, and trusses at selected locations on the structure, so that the existing East Span would be able to withstand a moderate earthquake. This work is expected to be completed by late 1998. The No-Build Alternative is evaluated primarily as a basis for comparison with the build alternatives.
S.3.2 Retrofit Existing Structure Alternative
The Retrofit Existing Structure Alternative would seismically retrofit and rehabilitate the existing East Span to withstand an MCE. The alignment of the bridge would remain unchanged. Improvements would be made to the existing structure and the East YBI Viaduct. These improvements would strengthen the substructure and modify the superstructure to permit large displacements at specified joints. In addition, two new piers would be added to the cantilever main span to provide additional support.
Replacement Alternative N-2 would construct a new bridge (two side-by-side bridge decks, each deck consisting of five lanes) north of the existing alignment and would dismantle the existing structure. The alignment has been designed to minimize the length of the new bridge by closely following the alignment of the existing East Span. East of the YBI Tunnel, the alignment would transition from a double-deck viaduct
structure to two parallel structures. The 3,585-meter (11,759-foot) long span would reach the Oakland shore along the northern edge of the existing Oakland Touchdown area and conform to the existing traffic lanes to the west of the SFOBB Toll Plaza. Alternative N-2 would include a pedestrian/bicycle path on the south side of the eastbound structure. The path would be 4.7-meter (15.5-foot) wide and 0.3 meter (1 foot) higher than adjacent traffic lanes.
Replacement Alternative N-6 is similar to N-2, but the proposed bridge would be aligned north of the existing structure and Alignment Alternative N-2. This alignment has been designed to maximize views to the north of YBI while minimizing intrusion into portions of the Bay where geologic conditions increase the complexity and cost of constructing bridge piers. The overall length of Alternative N-6 is approximately 3,620 meters (11,877 feet). The alignment approaching the Oakland Touchdown area is similar to Replacement Alternative N-2. Alternative N-6 would include a pedestrian/bicycle path on the south side of the eastbound structure. The path would be 4.7-meter (15.5-foot) wide and 0.3 meter (1 foot) higher than adjacent traffic lanes.
Replacement Alternative S-4 would be located south of the existing East Span. The alignment would exit the YBI Tunnel on a double-deck viaduct and transition to two parallel structures. The 3,550-meter (11,644-foot) long span would reach the Oakland shore south of the existing East Span and transition to the existing roadway west of the toll plaza. Alternative S-4 has been developed to avoid conflicts with the alignment of the existing East Bay Municipal Utility District (EBMUD) sewer outfall, which parallels the existing East Span to the south. Alternative S-4 would include a pedestrian/bicycle path on the south side of the eastbound structure. The path would be 4.7-meter (15.5-foot) wide and 0.3 meter (1 foot) higher than adjacent traffic lanes.
Design variations for main span type have been identified for consideration with each of the replacement alternatives. The span type variations include a cable stayed design, a self-anchored suspension design and a skyway design. Attributes and costs (2002 dollars) associated with each design variation are shown in Table S-1.
Table S-1 Replacement Bridge Design Variations
(in $ billions)
Source: Parsons Brinckerhoff, September 1998
S.3.7 Accommodation of Multi-Modal Strategies
While none of the project alternatives presented above would include facilities for high occupancy vehicle (HOV) lanes or rail transit, the existing East Span or a replacement span could accommodate a HOV lane or light rail transit (LRT) by converting vehicular traffic lanes or shoulders and making additional modifications. BART- or AMTRAK-type trains could not be accommodated on the East Span structure due to the combined length and weight of the trains. The purpose of such a facility would be to increase mobility within the Transbay Corridor.
The feasibility of incorporating a high occupancy transportation facility was evaluated as part of the East Span Project alternatives definition process. The evaluation determined that the implementation of a multi-modal strategy would have institutional and funding issues and adversely affect traffic operations on the SFOBB and its approaches. LRT strategies have not been evaluated at a system level, and no funding has been programmed or identified for either HOV lanes or LRT.
Since multi-modal strategies would reduce the number of mixed-flow traffic lanes, any multi-modal strategy must capture high ridership to match the loss in mixed-flow vehicular capacity on the SFOBB and its approaches. Otherwise, vehicular operations on the SFOBB and approaches would be comparatively worse than without the system. Substantial costs would be incurred to construct and operate an HOV or LRT system. Based on these potential impacts, neither dedicated HOV lanes nor an LRT system has been included in project alternatives.
The implementation of any multi-modal strategy on the SFOBB would be subject to independent evaluation and funding as a separate project in the future. The SFOBB East Span project does not preclude the implementation of an HOV lane or a rail system on the East Span in the future.
S.3.8 Alternatives Considered but Withdrawn
In addition to the alternatives considered above, Caltrans considered other project alternatives which were ultimately withdrawn from further consideration. These alternatives included the following: four northern alignments and three southern alignments for a replacement bridge with two side-by-side decks and a double-deck structure for either a northern or a southern alignment.
These alternatives were rejected for a variety of reasons, as described in Section 2.7.
Important considerations that contributed to rejection or withdrawal of alternatives included limitations on panoramic views, geologic conditions (deep Bay muds and distance to bedrock), not being able to meet American Association of State Highway and Transportation Officials (AASHTO) design standards, less than optimal roadway geometry, conflicts with the EBMUD sewer outfall, and constructablilty issues for the detour structures.
S.3.9 Design Variations Considered But Withdrawn
Replacement refinement studies evaluated variations for the bridge profile, which refers to the rise in roadway elevation from the Oakland Touchdown area to the YBI East Viaduct connection. A Constant Grade profile has been used in this analysis, although general preference was stated by the MTC Bay Bridge Design Task Force Engineering and Design Advisory Panel (EDAP) for the Elevated Grade profile variation The Constant Grade profile proved to be more cost effective than the Elevated Profile, while having a negative visual effect on the perception of the main span from a distance.
Two possibilities for the main span towers for the cable-stayed and self-anchored suspension design variations were examined. Following an evaluation of seismic safety, construction requirements, aesthetic considerations, and potential environmental impacts, the single-tower main span design option was recommended by the EDAP and a dual-tower option was withdrawn from further consideration.
Bicycle/pedestrian path options were considered by a Caltrans-hosted Bicycle/Pedestrian Advisory Committee. The committee considered replacement alternative design variations including a single path on one structure and dual paths, one on each structure. Caltrans also analyzed replacement alternatives without a path.
Based on recommendations of the committee and the approval by MTC to use toll revenues to fund a path, a single 4.7-meter (15.5-foot) wide path elevated 0.3 meter (1 foot) above the adjacent travel lanes has been added to the design of the eastbound structure in the N-2, N-6 and S-4 Replacement Alternatives.
S.4 ENVIRONMENTAL AND SOCIOECONOMIC IMPACTS AND PROPOSED MITIGATION MEASURES
The No-Build Alternative would not implement any project-related improvements and would therefore have no direct impacts. The existing bridge would continue to be vulnerable to damage in a major seismic event.
The Retrofit Existing Structure Alternative and all of the replacement alternatives would have some long-term (permanent) and short-term (construction-related) impacts on the physical and socioeconomic environment of the project study area.
Table S-3 (at the end of this chapter) provides a summary of the environmental effects of the project alternatives and proposed mitigation measures.
S.5 CONSULTATION AND COORDINATION
The FHWA and Caltrans are serving as joint lead agencies to prepare this Environmental Impact Statement/Statutory Exemption (CEQA). The U.S. Coast Guard is a cooperating agency.
This environmental document was prepared in consultation and coordination with various federal, state, and local agencies and organizations. Notable consultation and coordination activities are summarized below.
S.5.1 Project Organization and Committees
Several groups have been organized to advise the decision-makers for the East Span Project. Table S-2 lists the groups and their roles.
Table S-2 Project Advisory Groups
(Comprised of 31 local, state, and federal agencies; elected officials; special service districts; and professional organizations) (Comprised of technical experts in structural and civil engineering, seismicity and geology, and architecture) (Comprised of key members from ad-hoc bicycle, alternative transit, and public access groups) (Comprised of the East Bay Regional Park District, San Francisco Bay Conservation and Development Commission, Port of Oakland, City of Oakland, Oakland Landmarks Preservation Advisory Board, Oakland Army Base Reuse Authority, National Park Service and the Association of Bay Area Governments/Bay Trail, Caltrans staff, project consultants, and the U.S. Navy)
Project Development Team (PDT)
Serves as the technical advisory committee to Caltrans decision-makers. Meets periodically to address project issues, requiring technical direction or resolution.
Metropolitan Transportation Commission Bay Bridge Design Task Force
Coordinates local deliberations for the location, design and potential funding strategies for a replacement structure.
MTC Bay Bridge Design Task Force Engineering and Design Advisory Panel (EDAP)
Provides expert technical analysis and recommendations to the Task Force.
Bicycle/Pedestrian Advisory Committee (BPAC)
Represents the interest of the numerous groups advocating installation of a pedestrian/bicycle path in replacement alternatives.
Oakland Gateway Joint Planning Group
Coordinates efforts to establish a shoreline park in the Oakland Touchdown area.
NEPA/404 Integration Memorandum of Understanding (MOU) Process
Since August 1997, consultation has been ongoing with federal agencies, under the western states Memorandum of Understanding (MOU) for integrated NEPA/404 processing. Under the MOU process, the U.S. Fish and Wildlife Service (USFWS), National Marine Fisheries Service (NMFS), U.S. Army Corps of Engineers (ACOE), U.S. Environmental Protection Agency (EPA) and the Federal Transit Administration (FTA) have been asked to concur on the project purpose and need statement, criteria for alternative selection and range of alternatives to be considered. Three meetings have been conducted to date under the MOU process. At those meetings, participants considered the seismic safety-based project purpose and need statement and the range of alternatives proposed for evaluation. Following the meetings, written concurrence was received from each signatory agency. (Letters are presented in Appendix F.)
Other federal, state, and regional agencies with regulatory and permitting obligations for the East Span Project were invited to participate in the NEPA/404 MOU meetings. These include:
Coordination Pursuant to Section 106 of the National Historic Preservation Act
In April 1997, several organizations were invited to submit comments on the East Span Project with respect to historic properties. These organizations included:
In July 1997, Caltrans gave a brief presentation on the East Span Project to representatives of the Oakland Landmarks Preservation Advisory Board, Oakland Heritage Alliance, California Preservation Foundation, and San Francisco Landmarks Preservation Advisory Board. The Oakland Landmarks Preservation Advisory Board responded by letter on January 14, 1998, advocating that consideration be given to retrofit of the existing bridge rather than replacement and suggesting several mitigation measures if a replacement alternative is selected.
Since then, Caltrans and the Oakland LPAB have continued to coordinate regarding potential mitigation measures and other historic preservation issues associated with the East Span Project.
Outreach Meetings with the City of Oakland and City and County of San Francisco
Frequent meetings have been held with agency directors, planning officials, and others with the City of Oakland and the CCSF to discuss potential benefits and impacts of the project to each of the municipalities. Key concerns for the City of Oakland are the aesthetic qualities of the East Span and the Oakland Touchdown area, rail, and mitigation for impacts to the historic qualities of the existing East Span. Key concerns for the CCSF include the alignment alternatives, land use on YBI, and impacts to access ramps to and from YBI and Treasure Island.
During the preparation of this EIS, a variety of public participation activities have been conducted over the course of the engineering and environmental studies. The public has been encouraged to participate in the process by asking questions and making comments. Public involvement activities have included scoping meetings, environmental stakeholders meetings, open houses in Alameda, Contra Costa, San Francisco, and Solano counties, presentations to organized groups, and quarterly newsletters to over 3,500 interested parties. A total of 45 presentations were made to various public groups, agencies, and professional associations over the course of the project.
S.6 UNRESOLVED ISSUES AND AREAS OF CONTROVERSY
Issues of potential controversy associated with the East Span Project include accommodation of rail service on the bridge, disposal of dredged materials, future land use scenarios on YBI, and access ramps to and from YBI. The following is a summary of each issue:
The provision of adequate right-of-way to accommodate rail service on the replacement alternatives is an issue raised by some East Bay communities and the City and County of San Francisco. Although the fundamental obstacles to implementing rail service on the SFOBB as part of this project are discussed in this document, it is likely that additional public discussion of rail service on the SFOBB in the larger Transbay Corridor will continue.
Disposal of dredged materials at in-Bay or upland locations will be determined during the permitting stage of the project, which will occur in Summer 1999, after preparation of the Final EIS. It is anticipated by Caltrans that a portion of the dredged materials will be approved for disposal at an in-Bay location, since the Dredged Materials Management Office had granted conceptual approval for disposal of the dredge volumes associated with the Retrofit Existing Structure Alternative.
Potential land use impacts on YBI resulting from replacement alternatives are based on tentative information included in the TI/YBI Re-use Plan. Additional refinement of this issue will be required as the final design plans for the identified preferred alternative are developed and as land use planning decisions for YBI are made.
While not a component of the SFOBB East Span Seismic Retrofit Project, the ultimate ownership, redesign, and funding of new ramps on YBI is the subject of continuing discussion between Caltrans and the City and County of San Francisco. Caltrans does not currently own the ramps.
Required approvals are listed in a table at the end of Appendix E.
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[end of DEIS 02]
CHAPTER 1
PURPOSE OF AND NEED FOR PROJECT
The purpose of the San Francisco-Oakland Bay Bridge (SFOBB) East Span Seismic Safety Project (East Span Project) is to provide a lifeline vehicular connection that:
The SFOBB East Span Project will provide a seismically upgraded vehicular crossing for current and future users. SFOBB East Span Project replacement bridge alternatives will not preclude a pedestrian/bicycle path.
The existing East Span must be replaced or retrofitted because it is not expected to withstand an MCE on the San Andreas or Hayward faults, it does not meet "lifeline" criteria for providing emergency relief access following an MCE, and it does not meet current operations and safety design standards.
The project is proposed to address the following major transportation needs and deficiencies identified specifically on the bridge between YBI and the SFOBB Toll Plaza:
Each of these needs is described in the following sections.
1.2.1 "Lifeline" Connection - The existing SFOBB East Span does not provide a "lifeline" connection that is usable after an MCE.
Improvements to the existing East Span are needed to address seismic safety deficiencies and provide a bridge crossing that is usable soon after a major seismic event. It is likely that the existing SFOBB East Span would develop multi-span failures leading to collapse and loss of life in the event of an MCE. The East Span does not provide for public safety during an MCE.
Maximum Credible Earthquake
The seismic design criteria set for the East Span Project have been established as an 8 magnitude earthquake on the San Andreas Fault or a 7-1/4 magnitude earthquake on the Hayward Fault. The MCE on each of these faults is defined as the largest earthquake that appears to be reasonably capable of occurring based on current geological knowledge. However, these values could be exceeded. The probability of an MCE occurring on one of these faults is approximately one in four over the next two to three decades.
An MCE on either the San Andreas or Hayward faults would be expected to inflict far greater damage to the SFOBB than was experienced from the 1989 Loma Prieta earthquake. This is due to the potential for the epicenter of an event on either the San Andreas or Hayward faults to be nearer the bridge, as well as the expected greater magnitude of the MCE compared with that of the Loma Prieta earthquake (magnitude 7.1). It is estimated that an MCE with an 8 magnitude would generate in excess of 30 times more energy than the Loma Prieta earthquake. Feasibility of reopening the existing East Span to traffic following an MCE would be limited or precluded without the seismic safety improvements proposed in the East Span Project.
Lifeline Structure
The SFOBB provides a critical connection between San Francisco, the East Bay, and the I-80 corridor to the east. Designation by the California Department of Transportation (Caltrans) of the SFOBB corridor as a lifeline system connection represents the State’s intention to use the SFOBB to provide a high level of post-earthquake transportation service for emergency response and support for the economic livelihood of the Bay Area.
The criteria for state lifeline route designation and their applicability to the SFOBB East Span Project are listed below.
Cooperative earthquake response planning among Bay Area transportation providers focuses on the roles of agencies, including Caltrans, in post-earthquake response. Emphasis is placed on actions during the first 72 hours after an earthquake. Response scenarios do not call out procedures to be implemented at specified locations. Overall responsibilities for participating agencies are defined.
Caltrans preparedness planning consists of activities, including cooperation with the California Highway Patrol (CHP), in developing traffic control and evacuation procedures; activating emergency response resource centers; and establishing route recovery plans.
Although no detailed plan for a lifeline SFOBB post-earthquake use is defined, it can be anticipated that the structure would be used to transport heavy equipment, such as cranes and bulldozers, to work sites. The structure would also be used to distribute supplies from the San Francisco and Oakland ports to recovery centers. Automobile and bus transit traffic would likely be banned from the SFOBB so as not to interfere with emergency response, then would be restored on the SFOBB East Span as feasible. As a lifeline vehicular bridge, the SFOBB East Span would have the flexibility to move equipment and goods during post-earthquake recovery that cannot be accommodated by Bay Area Rapid Transit (BART) and ferry service.
1.2.2 People, Freight, and Goods Movement - The existing SFOBB East Span cannot maintain high levels of freight and goods movement following an MCE.
The SFOBB East Span, currently operating at capacity, accommodates approximately 274,000 vehicles each day. These vehicles transport approximately 350,000 people daily between San Francisco and Oakland, making the East Span a critical transportation link in the Bay Area. Providing a seismically safe lifeline vehicular bridge crossing is critical to retaining the ability to move high volumes of people between San Francisco, the San Francisco Peninsula, and the East Bay.
The SFOBB is a primary route for movement of freight and goods between the San Francisco Peninsula and the East Bay. It provides access for San Francisco to the intrastate and interstate trucking network in the East Bay and beyond. The SFOBB provides a link for seaport cargo and air freight delivery between the ports and airports in both San Francisco and Oakland. The bridge is also a link for local delivery of freight and goods. The SFOBB carries the greatest amount of total traffic and truck traffic of the Bay Area toll bridges (see Table 1.2-1). Maintaining the capacity of the East Span to accommodate large volumes of truck traffic is important for distribution of freight and goods to facilitate economic recovery following an MCE. Disruption of this critical link in the transportation system by damage or failure due to an earthquake would require rerouting approximately 11,000 truck trips per day to other toll bridges - assuming these other bridges are not similarly damaged. Extended interruption of the capacity of the East Span to accommodate large numbers of trucks would have an adverse effect on the local and regional economy.
Table 1.2-1 Average Annual Daily Total Traffic and Truck Traffic on Bay Area Toll Bridges
|
Bridge |
AADT |
AADT |
|
|
| SFOBB |
274,000
|
11,508
|
4.2
|
40
|
| Dumbarton |
59,000
|
2,283
|
3.8
|
34
|
| San Mateo-Hayward |
77,000
|
5,040
|
6.5
|
42
|
| Golden Gate |
118,000
|
1,888
|
1.6
|
35
|
| Richmond-San Rafael** |
52,000
|
3,623
|
6.9
|
43
|
| Carquinez |
105,000
|
6,405
|
6.1
|
59
|
| Benicia-Martinez |
91,000
|
7,007
|
7.7
|
50
|
Source: 1996 Average Annual Daily Truck Traffic on the California State Highway System, Caltrans, October 1997.
*Percentage of 4- and 5-axle trucks of total trucks.
**Measurement location at junction of I-580/Route 101, Marin County.
1.2.3 Current Roadway Design Standards - The existing SFOBB East Span does not meet current roadway design standards for operations and safety.
Design standards are applied to bridge and roadway projects to provide a safe facility. The SFOBB East Span, constructed in the 1930s, does not meet all of the current mandatory and advisory design standards. Features of the current bridge that do not meet current standards are:
1.3.1 The San Francisco-Oakland Bay Bridge
The SFOBB is historically important in the Bay Area and world wide. Construction of this structure began in 1933 and was completed and opened to traffic in 1936. At the time of its construction, the bridge was the world’s longest vehicular bridge, and the YBI Tunnel, a double-decked structure, was the largest bore tunnel of its time at 23 meters (76 feet) long by 15 meters (50 feet) wide by 15 meters (50 feet) high (see Figure 1-1 in Appendix A).
The "Key System" was an electrified interurban, light-rail system that utilized the south side of the lower deck of the East and West Spans of the SFOBB. It shared the lower deck with trucks and buses, while automobile traffic traveled in six lanes on the upper deck. The Key System commenced operation in 1939 and continued service until 1958. Between 1939 and 1941, two other rail lines, the Interurban Electric and the Sacramento Northern, also operated on the SFOBB.
The Key System connected Oakland and Berkeley with San Francisco. The system terminated in San Francisco at the Transbay Transit Terminal where passengers could transfer to the San Francisco Muni system. In total, the Key System trains operated on 106 kilometers (66 miles) of track on the SFOBB and in the East Bay.
Patronage on the Key System peaked in 1945 with 37,334,000 passengers annually. By 1957, ridership had declined to about 6 million. Daily ridership in 1945 was 102,228 passengers and 16,747 passengers in 1957. As a result of the decrease, the Key System rail lines were abandoned and the routes were converted to AC Transit bus service in 1958.
When Key System rail service ended, the lower deck of the SFOBB was converted to automobile use. To accommodate these changes, significant modifications were made in San Francisco, on the SFOBB, YBI, and in the Oakland Touchdown area, including new additional access to and from the SFOBB, removal of the track ties and other railroad facilities from the lower deck of the SFOBB, and construction of new roadways to and from the SFOBB in Oakland.
The SFOBB currently serves approximately 350,000 people in the 274,000 vehicles that use the bridge each day. The SFOBB provides regional access between the San Francisco Peninsula and the East Bay. As a component of Interstate 80 (I-80), it is a critical link in the interstate network. The Dwight D. Eisenhower System of Interstate and Defense Highways, established during Eisenhower’s presidency in 1954, is a network of access-controlled and grade-separated highways designed to serve the national defense and to connect states and routes of continental importance in Canada and Mexico.
The SFOBB is a double-deck structure carrying five traffic lanes on each level. The West Span connects San Francisco to YBI. A concrete viaduct and approach ramps eastward from Fifth Street in San Francisco at the west end, 1,130 meters (3,707 feet) long, connect to the two suspension spans, each over 1,400 meters (4,593 feet) long. On the island, there are two concrete viaducts, 165 meters (541 feet) and 65 meters (213 feet) in length, at either end of the 164.4-meter (539-foot) long double-deck tunnel.
The East Span is the portion of the structure between YBI and Oakland. A 800-meter (2,625-foot) long viaduct extends from the YBI Tunnel east portal eastward across the island. A series of steel truss spans carry the highway across the eastern portion of the Bay. The steel spans include a 737-meter (2,418-foot) cantilever truss adjacent to the island, followed by five high truss spans 155.1 meters (509 feet) each, and 14 shorter spans, which bring the roadways to the East Bay shoreline.
1.3.2 Effects of the Loma Prieta Earthquake and a Maximum Credible Earthquake
On October 17, 1989, the Loma Prieta earthquake struck the San Francisco Bay Area. Its epicenter was in a sparsely populated area of the Santa Cruz Mountains, 97 kilometers (60 miles) away from the SFOBB. The Office of Emergency Services (OES) reports that the earthquake caused 62 deaths and $5.6 billion in property damage and 8,000 people were left homeless. Over 1,300 buildings were destroyed and 20,000 buildings were damaged. On the SFOBB, the earthquake caused a portion of the upper deck of the East Span to collapse onto the lower deck, resulting in one death. The East Span was closed for four weeks while the damage was repaired. It is estimated that the increased delay experienced by commuters rerouted to other Bay crossings, including other modes such as ferries or BART, cost as much as $12 million.
An MCE on the San Andreas fault could generate over 30 times more energy than the Loma Prieta earthquake. But an MCE on the Hayward fault could generate about the same energy as the Loma Prieta earthquake. Heavy damage could be much more widespread, including the collapse of thousands of buildings, extensive infrastructure damage, and major loss of life. The magnitude of such a natural disaster would necessitate the kind of emergency access provided by the bridge retrofitted to lifeline standards. On the existing SFOBB East Span, an MCE could cause catastrophic bridge failure, potentially resulting in numerous immediate casualties and requiring many months to reopen the bridge or years to build a replacement. Immediate emergency response and more long-term economic recovery would be delayed.
1.3.3 Analysis of Potential Retrofit of SFOBB East Span
Caltrans began action following the Loma Prieta earthquake to design seismic safety improvements for the SFOBB East Span. Seismic safety strategies initially investigated focused on retrofit of the existing East Span structure. A retrofit alternative was devised and initial environmental review conducted. Consultation with permitting and regulatory agencies was initiated.
An important consideration for the retrofit of bridges maintained by Caltrans is the cost of upgrading the existing structures to current seismic criteria measured against the remaining useful life of the bridges. Caltrans has developed a cost/benefit formula to assist in the determination of the need to retrofit a bridge compared to replacing it. First it must be determined that there is a viable retrofit alternative (i.e., the existing structure can be retrofitted to meet seismic safety criteria established for the structure). This decision is made by Caltrans with input from a Seismic Advisory Board, an industry and academic advisory panel which was established following the Loma Prieta earthquake, to provide Caltrans assistance in determining effective seismic safety technologies.
The Caltrans formula takes into account both construction costs and life-cycle costs. Cost comparisons of retrofit and replacement alternatives indicated that seismic retrofit of the existing span could be accomplished at a lower cost than the cost to replace the structure. However, replacement bridge alternatives would have lower life-cycle costs; therefore, consideration of bridge replacement was recommended by Caltrans and the Business, Transportation and Housing Agency to Governor Pete Wilson.
1.3.4 Analysis of Potential Replacement of the SFOBB East Span
In February 1997, Governor Pete Wilson adopted the recommendations of the Business, Transportation and Housing Agency and Caltrans that replacement of the SFOBB East Span be considered. The Metropolitan Transportation Commission (MTC) organized the San Francisco-Oakland Bay Bridge Design Task Force (Task Force) to consider replacement bridge alternatives. Alternatives under consideration in this environmental document include replacement options defined through the Task Force proceedings. The Task Force mandate is to develop a consensus recommendation on a design option for a new eastern span of the SFOBB and recommend any additional features that might be included in the design of the bridge that would not be borne by funding allocated from the State of California. A description of the MTC process is provided in the Preface and Appendix E: Consultation and Coordination, of this Draft EIS.
1.3.5 Other SFOBB Seismic Safety Projects
Caltrans is undertaking a number of independent actions to address the overall need of providing a lifeline bridge connection between the cities of San Francisco and Oakland. In combination, these actions will provide for a lifeline structure connecting San Francisco and the San Francisco Peninsula to the East Bay. The individual projects, in addition to contributing to the seismic safety improvement of the SFOBB, have been defined to contribute independently to seismic safety of bridge users in the event of an MCE. As each of the projects is completed, bridge users will benefit from seismic safety improvements and specific lifeline access issues will be resolved.
In addition to the East Span Project, Caltrans is undertaking other actions to seismically retrofit the SFOBB. These projects are shown in Figure 1-1 and consist of:
The California Legislature has in various legislative findings and declarations expressed its intent to complete the seismic retrofit of State-owned and State-operated highways. Following the 1971 San Fernando Valley earthquake, seismic design standards for transportation facilities were reassessed in light of the unanticipated damage to certain roadway structures, and a retrofit program was begun. The extensive roadway damage caused by the 1989 Loma Prieta earthquake in northern California and the 1994 Northridge earthquake in southern California prompted an acceleration of the retrofit program, including several efforts to increase program funding. In 1991, the legislature authorized financing seismic retrofit projects from motor vehicle fuel tax revenues and additional funding mechanisms, declaring that "it is in the best interests of the people of California to immediately finance retrofit projects to make state highways safe during seismic events, and to offset any possible delays caused by these projects on approved state highway projects contained in the state transportation improvement program for 1990..." (Government Code, Chapter 5, Article 1, Amended: Statutes of 1991, Chapter 195).
In 1995, recognizing the increasing financial drain of the ongoing seismic retrofit program on limited funding resources, the legislature placed the Seismic Retrofit Bond Act of 1996, or Proposition 192, on the March 1996 ballot, declaring that "the completion of seismic safety retrofit work is essential to the welfare and economy of the state," (Government Code, Title 2, Division 1, Chapter 12.48, Article 1). This act, approved by the voters in 1996, authorized the sale of over $2 billion in state revenue bonds for financing retrofit improvements and temporarily suspended state statutes that were deemed to potentially delay or unnecessarily encumber their implementation. The seismic retrofit and rehabilitation of the SFOBB East Span is a priority project under the state’s accelerated retrofit program.
Senate Bills 226 and 60 were passed by the State Legislature and signed into law by the Governor on August 20, 1997. Together, these bills provide a financing mechanism and identify funding sources for seismic improvements for Bay Area toll bridges, including the SFOBB East Span. Senate Bill 226 reassigns programming authority for Bay Area toll bridges from the California Transportation Commission to the Metropolitan Transportation Commission, superseding the state Toll Bridges Program. Senate Bill 60 sets a one dollar toll surcharge on all Bay Area toll bridges, including the SFOBB, and identifies State Highway Account funds available for seismic upgrades.
Implementation of the East Span Project will be funded from a combination of sources. Approximately 36.5 percent of project costs will be funded by state fuel tax revenues earmarked for seismic upgrade projects. State Seismic Retrofit Revenue Bonds issued by the state after voter approval of Proposition 192 in March 1996 will fund an additional 27 percent. The one dollar toll surcharge on Bay Area toll bridges for eight years will fund the remaining 36.5 percent. The toll surcharge can be funded for up to two additional years to pay for bridge amenities. These include a cable-supported or other "signature" bridge design, the Transbay Transit Terminal (including possible relocation and/or ramp reconfiguration), and the addition of pedestrian/bicycle access on the SFOBB.
Seismic retrofit projects, including the East Span Project, are exempt from the requirements of the California Environmental Quality Act (CEQA) under California Streets and Highways Code Section 180.2 and CEQA Section 21080 (see Chapter 5). Although CEQA review will not be conducted for the project, detailed environmental and socioeconomic review is being undertaken to comply with the National Environmental Policy Act (NEPA). The East Span Project will also be subject to the permitting requirements of federal and state regulatory agencies. Consultation is under way with public agencies, including U.S. Coast Guard, U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, Advisory Council on Historic Preservation, Metropolitan Transportation Commission, National Marine Fisheries Service, San Francisco Bay Conservation and Development Commission, California Department of Fish and Game, State Historic Preservation Officer, State Lands Commission, San Francisco Bay Regional Water Quality Control Board, and the Association of Bay Area Governments.
[end of DEIS 03]
CHAPTER 2
PROJECT ALTERNATIVES
This chapter describes the alternatives that are analyzed in this Draft Environmental Impact Statement (DEIS), along with the various design options under consideration. This chapter also describes project alternatives that were initially considered but were withdrawn from consideration prior to preparation of this document, and the reasons for their withdrawal.
The Metropolitan Transportation Commission (MTC) is the transportation planning, coordinating, and financing agency for the nine-county San Francisco Bay Area. It functions both as the region’s metropolitan transportation planning agency (RTPA) and as the region’s metropolitan planning organization (MPO)—state and federal designations, respectively. The Regional Transportation Plan (RTP) which MTC prepares, is a comprehensive guide for the development of mass transit, highway, airport, seaport, railroad, bicycle, and pedestrian facilities within the Bay Area. The MTC also allocates state and federal funds for transportation projects based on compatibility with this plan.
MTC, based on recommendations from its Bay Bridge Design Task Force, has stated a preference for a northern replacement alignment bridge with a self-anchored suspension main span and a pedestrian/bicycle path along the south side of the eastbound deck. The MTC recommended alternative is included in this EIS as Replacement Alternative N-6, self-anchored suspension design variation. The California Department of Transportation (Caltrans) and the Federal Highway Administration (FHWA) have not identified a preferred alternative in this Draft EIS.
The Federal Highway Administration (FHWA), pursuant to the 1991 Intermodal Surface Transportation Efficiency Act, as amended, prepares a Major Investment Study (MIS) for "highway improvements that are expected to have a significant effect on capacity, traffic, level of service or mode share. FHWA prepares MIS’s at the transportation corridor or sub-area level to address federally funded projects. Because the East Span Project is not federally funded and is a seismic safety project that does not change current bridge capacity, no MIS has been produced.
Pursuant to the National Environmental Policy Act (NEPA), all alternatives currently under consideration are analyzed to an equal level of detail in later sections of this document. Identification of the project preferred alternative will occur after this document is circulated for a 45-day public review period and all public comments are received and considered.
Since the No-Build Alternative does not satisfy the project purpose and need in terms of seismic safety, it is presented and evaluated primarily as a basis of comparison with the other alternatives. As noted in Chapter 1, Caltrans is currently adding seismic strengthening elements to the existing East Span structure as an interim measure. That project has received environmental approval pursuant to NEPA and is not evaluated as an alternative in the Draft EIS. The No-Build Alternative assumes completion of this interim work.
The proposed project seeks to retrofit or replace the existing San Francisco-Oakland Bay Bridge (SFOBB) East Span, which has connected Oakland and Yerba Buena Island (YBI) since 1936. The purpose of the SFOBB East Span Seismic Safety Project (East Span Project) is to provide a seismically upgraded "lifeline" vehicular crossing for current and future users. This project is one of several that Caltrans is undertaking to address the overall need of providing a lifeline bridge connection between the East Bay, San Francisco, and the San Francisco Peninsula. The other projects include replacing the West Approach to the SFOBB West Span in San Francisco, retrofitting the West Span, West YBI Viaduct, and YBI Tunnel, and the interim retrofit on the East Span (see Section 1.3.5).
2.1.1 Development of Alternatives
Caltrans has considered and performed preliminary engineering on a range of possible project alternatives for inclusion in this Draft EIS. The retrofit and replacement alternatives, along with the No-Build Alternative, are described in Section 2.2. Replacement bridge design variations that are under consideration are described in Section 2.3. Section 2.4 provides a comparison of the alternatives’ characteristics, including costs, constructibility, and potential to meet the purpose and need. Section 2.5 discusses multi-modal options for alternatives, and Section 2.6 describes construction scenarios for each of the build alternatives. Section 2.7 describes the alternatives, design variations, and temporary detour options that were considered and subsequently withdrawn from further consideration and the reasons for their withdrawal.
The range of alternatives considered in the Draft EIS was established by Caltrans and FHWA in accordance with NEPA requirements and in consultation with permitting and regulatory agencies under guidance of the NEPA/404 Integration Memorandum of Understanding (NEPA/404 MOU). The NEPA/404 integration process is implemented when a project has the potential to affect waters of the U.S. under the jurisdictional authority of the U.S. Army Corps of Engineers (ACOE). Participants considered options and provided written concurrence in the range of alternatives and the criteria established for evaluation of alternatives. (See Appendix F for the concurrence letters from the NEPA/404 signatories.)
The SFOBB crosses San Francisco Bay in an east-west direction in the central portion of the San Francisco Bay Area and provides a travel route between San Francisco and Alameda counties. The bridge touches down near Pier 26 in San Francisco and in northwest Oakland between the East Bay Municipal Utility District (EBMUD) water treatment facility and the Emeryville Crescent tidal marsh. The west and east spans of the bridge are connected on YBI by viaduct sections on either side of the YBI Tunnel. A navigation channel is located between piers E-2 and E-3 of the SFOBB East Span. The channel, shown on Figure 2-2 (Appendix A), is 427 meters (1,400 feet) wide, with vertical clearance of 60 meters (197 feet) above Mean Sea Level (MSL). The East Span Project will retrofit or replace the portion of the SFOBB between the east end of the tunnel on YBI and the SFOBB Toll Plaza (toll plaza) in Oakland. Figure 2-1 (Appendix A) shows the project location and Figure 2-2 (Appendix A) shows the project area limits.
The East Span Project is in San Francisco and Alameda counties. The western project limit is the west portal of the YBI Tunnel. The eastern project limit is the SFOBB Toll Plaza on a spit of land referred to as the Oakland Touchdown area. The project area is defined as the area within the project limits in which temporary and permanent structures would be placed by any of the alternatives and defines the area within which construction activities, including detours, would be expected to occur. The project area widens over water to allow for marine construction activities. In addition, Bay waters on the north side of YBI are included within the project area to allow staging for large construction equipment and bulk materials to be delivered to YBI by barge or vessel.
Five alternatives, No-Build, Retrofit Existing Structure, Replacement Alternatives N-2, N-6, and S-4, are currently under consideration for the East Span Project. Alternatives N-2 and N-6 are aligned to the north of the existing SFOBB and Alternative S-4 aligns south of the existing bridge (see Figure 2-3 in Appendix A). Alignment drawings for the build alternatives are presented in Appendix A. Detour structures will be required on YBI for the three replacement alternatives (N-2, N-6, and S-4) in order to reroute traffic around the construction area while portions of the existing East Span are dismantled and a new transition structure is completed where the existing bridge now stands on YBI.
In order to connect the new bridge with the viaduct on YBI and the toll plaza at the Oakland Touchdown area, all three replacement alternatives would require dismantling the existing East Span facility. A description of the dismantling process is described in Section 2.6.3.
The No-Build Alternative would retain the existing SFOBB East Span. The No-Build Alternative assumes some seismic improvements to the East Span have been completed as a prior project. The Interim Retrofit Project is currently under way to strengthen bents and columns on the viaduct section on YBI and strengthen or toughen piers, bents, and trusses at selected locations on the structure, so that the existing East Span would be able to withstand a smaller but more likely earthquake. This work is expected to be completed by late 1998. The No-Build Alternative is evaluated primarily as a basis for comparison with the build alternatives. (Note: The Interim Retrofit Project was environmentally approved with a Statutory Exemption under CEQA and a Categorical Exclusion under NEPA.)
2.2.2 Retrofit Existing Structure Alternative
This alternative would retrofit the existing 3,696-meter (12,127-foot) long SFOBB East Span to withstand an MCE, but would not provide a lifeline crossing. This alternative would retrofit the existing SFOBB East Span to withstand an MCE on the San Andreas or Hayward faults; however, it would not provide a lifeline connection. Although substantial modifications to the cantilever section are proposed as a part of the Retrofit Existing Structure Alternative, it is nevertheless anticipated that the cantilever section would experience substantial damage and require extensive reconstruction or replacement following an MCE. If damage is such that reconstruction of the cantilever section is feasible, this may require complete closure of the East Span from six months to one year. If, however, damage is sufficiently severe that replacement becomes necessary, the East Span would be completely closed for a substantially longer period of time. The Retrofit Existing Structure Alternative would retrofit both the existing East Span and the east viaduct section on YBI. The alignment of the bridge would remain unchanged and the bridge would remain a double-deck structure. (See Figures 2-4.1,2-4.2, 2-4.3, 2-4.4 in Appendix A.) Each deck roadway cross section would also remain the same, five 3.5-meter (11.5-foot) wide lanes with no roadway shoulders. The construction period for this alternative is estimated to be four years.
The seismic retrofit strategy for the Retrofit Existing Structure Alternative is based on strengthening and stiffening of the substructure (below deck, towers, and foundations). Large diameter piles would be added around the perimeter or on both sides of all existing foundations. New, larger pile caps would be constructed to join the expanded foundations. Figures 2-5 and 2-6 (Appendix A) show the "before" condition and "after" simulation of the retrofitted bridge.
The tower legs in the navigation channel would be encased in concrete. Isolator bearings would be installed on the top of the towers to isolate the superstructure from the most damaging earthquake motions. Isolator bearings are used to allow horizontal movement in extreme earthquake events.
Two new piers (bridge support columns founded in water) would be added to the cantilever main span just east of YBI. Pier E2, which would be encased in concrete, would have two new piers, E2A and E2B, on the west and east sides (see Figures 2-4.1 and 2-4.2 in Appendix A for locations of new piers). The seismic retrofit strategy would add a new edge truss to restrict deformations in the cantilever section. An edge truss is trusswork that is extended from the base of the lower deck to the bottom of the upper deck.
The Retrofit Existing Structure Alternative would modify the superstructure to permit large displacements (movements) at specified joints in the event of an earthquake. Retrofitting of truss members would include wind bracing and strengthening, floor grid, and vertical members.
The Retrofit Existing Structure Alternative would strengthen the east viaduct and piers. The substructure of the east viaduct would be retrofitted by encasing columns and footings in concrete, providing cast-in-drilled-hole piles/tie downs under the footings, and installing isolator bearings at the top of columns. Piers YB2, YB3, and YB4 would be encased in concrete and foundations expanded.
2.2.3 Replacement Alternative N-2
Replacement Alternative N-2 would construct a 3,585-meter long (11,759-foot long) new bridge north of the existing East Span and dismantle the existing structure. (See Figures 2-7.1, 2-7.2, 2-7.3, 2-7.4 and 2-7.5 in Appendix A). The N-2 alignment parallels the existing bridge and maintains minimal clearance between the old and new structures to accommodate construction of the new bridge and dismantling the existing structure.
Replacement Alternative N-2 begins at the eastern portal of the YBI Tunnel. The existing YBI East Viaduct would be retrofitted. At Bent 48 (sees Figure 2-7.1a and 2-7.1b in Appendix A), the new bridge begins with a new transition structure separating the double-decked lanes to two parallel structures. Outrigger "frame" supports would be used to support the upper deck as the lower deck transitions to a structure parallel with the upper deck. The parallel structures curve, enter a tangent or straight section over the existing navigation channel, curve, and align on tangent toward the Oakland Touchdown area. The parallel structures reach the Oakland shore along the northern edge of the existing Oakland Touchdown area and conform to the existing traffic lanes to the west of the toll plaza.
Alternative N-2 would consist of two parallel structures supported by 22 piers over water and 19 bents supported by columns set on YBI and the Oakland Touchdown area. The structures would each be 25.07 meters (82 feet) wide and separated by 15 meters (50 feet). The typical roadway section for each bridge deck consists of five lanes, each 3.6 meters (12 feet) wide, left and right shoulders, each 3 meters (10 feet) wide, and traffic barriers. A 4.7-meter (15.5-foot) pedestrian/bicycle path would be located on the south side of the eastbound deck, 0.3 meter (1 foot) above the roadway elevation. A typical roadway cross section is presented in Figure 2-8 in Appendix A.
The height of the bridge, including the transition structure and the parallel structures, would vary in elevation from 50-55 meters (164-180 feet) above MSL at the east viaduct on YBI to 5 meters (16 feet) above MSL at the Oakland Touchdown. A typical profile for replacement alternatives is presented in Figure 2-9 in Appendix A.
2.2.4 Replacement Alternative N-6
Replacement Alternative N-6 would construct a 3,620-meter long (11,877-foot long) new bridge north of the existing East Span and dismantle the existing structure. (See Figures 2-10.1 through 2-10.5 in Appendix A). The N-6 alignment is aligned to minimize the depth to bedrock for a cable-supported structure. The N-6 alignment curves northward from the existing East Span to maximize panoramic views of the East Bay Hills for eastbound bridge users and San Francisco skyline views for westbound bridge users. The northern limit of the alignment has been set to provide optimum views while minimizing intrusion into portions of the Bay where less favorable geologic conditions increase complexity and cost of constructing bridge piers and foundations.
The N-6 Replacement Alternative begins at the eastern portal of the YBI Tunnel. Part of the existing YBI East Viaduct would be retrofitted, modified, and partially demolished. At Bent 48 (see Figures 2-10.1a-2-10.1c in Appendix A), the new bridge begins with a transition structure separating the double-decked lanes into two parallel structures. Outrigger "frame" supports would be used to support the upper deck as the lower deck transitions out from below and parallel to the upper deck. The parallel structures curve, enter a tangent or straight section over the existing navigation channel, curve, then align on tangent toward the Oakland Touchdown area. The parallel structures reach the Oakland shore along the northern edge of the existing Oakland Touchdown area and conform to the existing traffic lanes to the west of the toll plaza.
Replacement Alternative N-6 consists of two parallel structures supported by 21 piers over water and 21 bents set on YBI and the Oakland Touchdown area. The structures would each be 25.07 meters (82 feet) wide and typically separated by 15 meters (50 feet). The typical roadway section for each bridge deck consists of five lanes, each 3.6 meters (12 feet) wide, left and right shoulders, each 3 meters (10 feet) wide and traffic barriers. A 4.7-meter (15.5-foot) pedestrian/bicycle path would be located on the south side of the eastbound deck, 0.3 meter (1 foot) above the roadway elevation. A typical cross section is presented in Figure 2-8 in Appendix A.
The height of the bridge, including the transition structure and the parallel structures, would vary in elevation from 50-55 meters (164-180 feet) above MSL at the east viaduct to 5-10 meters (16-33 feet) above MSL at the Oakland Touchdown. A typical profile for replacement alternatives is presented in Figure 2-9 in Appendix A.
2.2.5 Replacement Alternative S-4
Replacement Alternative S-4 would construct a 3,550-meter (11,644-foot) bridge south of the existing East Span and dismantle the existing structure. (See Figures 2-11.1 through 2-11.5 in Appendix A). The S-4 Alternative was developed to minimize bridge length and to avoid use of flat land to the north of the existing East Span on YBI while avoiding conflicts with the alignment of the EBMUD sewer outfall that aligns to the south of the existing East Span.
The S-4 alignment begins at the eastern portal of the YBI Tunnel. The existing YBI East Viaduct would be retrofitted. At Bent 48 (see Figures 2-11.1a and 2-11.1b in Appendix A), the new structure begins with a new transition structure separating the double-decked lanes to two parallel structures. Outrigger "frame" supports would be used to support the upper deck as the lower deck transitions to a structure parallel with the upper deck. The parallel structures curve, enter a tangent or straight section over the existing navigation channel, curve gradually, and align toward the Oakland Touchdown area. The parallel structures reach the Oakland shore to the south of the existing East Span and transition to the existing roadway west of the toll plaza.
Replacement Alternative S-4 would consist of two parallel structures supported by 23 piers over water; and 19 bents supported by columns, set on YBI, and the Oakland Touchdown area. The structures would each be 25.07 meters (82 feet) wide and separated by 15 meters (50 feet). The typical section for each bridge deck consists of five lanes, each 3.6 meters (12 feet) wide, left and right shoulders, each 3 meters (10 feet) wide and traffic barriers. A 4.7-meter (15.5-foot) pedestrian/bicycle path would be located on the south side of the eastbound deck, 0.3 meter (1 foot) below the roadway elevation. A typical roadway cross section is presented in Figure 2-8 in Appendix A.
The height of the bridge, including the transition structure and the parallel structures, would vary in elevation from 50-55 meters (164-180 feet) above MSL at the east viaduct to 5 meters (16 feet) above MSL at the Oakland Touchdown. A typical profile for the replacement alternatives is presented in Figure 2-9 in Appendix A.
Replacement alternatives are proposed as two parallel skyway structures, each having five traffic lanes, inside and outside shoulders, and a pedestrian/bicycle path on the eastbound deck. Design variations identified for the replacement alternatives are limited to the type of bridge to be constructed over the navigation channel. The bridge type variations apply only to the navigational portion of the crossing because the shallow water and the deep muds along 85 percent of the crossing necessitate the skyway design proposed for all of the replacement alternatives and design variations.
In addition to the design variations addressed here, certain refinements to the replacement alternatives will occur as bridge design advances. Based on the preliminary engineering design completed to date for a typical structure, replacement alternatives could be constructed of either steel or concrete. Steel and concrete are under evaluation for both skyway superstructure and main span tower options. Alternatives constructed of either material can be used to construct a bridge that meets lifeline criteria. Detailed analyses of costs, material availability, maintenance requirements, and effects to construction schedule will need to be conducted as design advances to determine the optimum construction material.
Final selection of the type of girder used to support the superstructure will also be determined based on engineering analyses yet to be completed. Options for a haunched girder, a variable depth beam between support piers, or a straight, constant depth girder will be evaluated. Selection of the superstructure type used for the bridge will be based on analyses of costs, material availability, maintenance requirements, and effects to construction schedule.
Additional design amenities will be added to the bridge as the design process moves to the next phase. Detailed amenities include railing design, lighting, and other elements which will refine the final design.
Design options are being considered for the main span section of the alignment, which runs from the YBI viaduct, east across the navigation channel, then transitions to a skyway design to the Oakland Touchdown area. A number of bridge types have been evaluated based on seismic performance, aesthetic considerations, and ability to construct the bridge within the expedited construction schedule. Bridge types for the main span have been narrowed to two: cable-stayed design and self-anchored suspension design. Both main span types would include a tower of 58 meters (520 feet) in height. Additionally, both main span types would maintain the navigation channel east of YBI.
In addition to the two main span types, a third variation is to construct a skyway along the entire SFOBB East Span crossing. The skyway would also maintain the navigation channel near YBI.
The cable-stayed design includes the use of steel cables to connect the bridge deck directly to the towers. Most cable-stayed bridges have one or two towers. A single concrete vertical tower is being considered for the East Span Project (See Figure 2-12 in Appendix A). Cable-stayed bridges have been used in several different countries since the 1940s. Recent examples constructed in the United States include the Sunshine Skyway in Tampa, Florida, and the Thomas Bridge in Georgia.
The cable-stayed system allows for longer spans crossing the navigational channel than could be provided with a skyway variation which requires additional piers to provide structure supports; however, it imposes additional alignment constraints. To support the two decks from a single tower, the decks of each of the parallel bridge structures must be almost parallel and at the same approximate elevation for the entire length of the main span. The main span cannot begin until each deck alignment meets these constraints. The replacement alignments under consideration have been set to accommodate the geometric requirements for a cable-stayed main span.
The cable-stayed main span would cost approximately $82 million more than the total estimated cost of an island-to-shore skyway replacement bridge.
The suspension design is a commonly used design for long channel crossings and has been used previously in the Bay Area on the Golden Gate Bridge and the SFOBB West Span. A classical suspension bridge has cables that are draped from towers and connected to anchorages on either side of the bridge. Vertical cables support the bridge by connecting the draped cable to the bridge deck. Poor ground conditions exist in the East Span Project area, making use of anchorage structures difficult or infeasible. A self-anchored suspension design variation is being considered. In a self-anchored suspension bridge, the cables are linked to the ends of the bridge deck, eliminating the need for anchorage structures (See Figure 2-13 in Appendix A). The single-tower self-anchored suspension design variation suspends the bridge from a single steel tower. Alignment constraints for the self-anchored suspension design variation are similar to those described for the cable-stayed design variation. Decks of the bridge structures must be almost parallel and at the same approximate elevation for the entire length of the main span. The main span cannot begin until each deck alignment meets these constraints. Although a self-anchored suspension bridge looks similar to more conventional suspension bridges, the bridge deck, as an integral structural component, requires unique engineering design. The replacement alternatives under consideration have been set to accommodate the geometric requirements for a self-anchored suspension design variation.
The self-anchored suspension main span would cost about $175 million more than the total estimated cost of an island-to-shore skyway replacement bridge.
The skyway design variation is a structure constructed of either concrete or steel, supported from under the bridge by piers. With this structure type, each bridge would be constructed as a separate, independent structure. Under the skyway design variation, spans over the navigation channel area could be a maximum of 150-170 meters (490-550 feet) in length. The skyway design variation would require three spans in the main span area, compared to two spans for both the cable-stayed and self-anchored suspension design variations. The skyway does not require a tangent or straight section over the main span which is needed to construct the cable-supported design variations. The N-2, N-6, and S-4 replacement alternatives have been set to accommodate any of the three design options. An example of a skyway structure is depicted in Figure 2-14 in Appendix A.
The skyway design variation is considered as the baseline for cost comparative purposes.
2.4 COMPARISON OF ALTERNATIVE CHARACTERISTICS
The base budget for the East Span Project, established in Section 188 of the California Streets and Highways Code (CSHC), is about $1.3 billion. Project funding comes from a combination of state taxes, bond revenues, and moneys collected through a one dollar bridge toll surcharge effective January 1, 1998, on all state-owned bridges in the Bay Area. State taxes, in the form of state fuel tax revenues, are 36.5 percent of the project budget. State Seismic Retrofit Bond revenues will fund 27 percent of the budget, and the toll surcharges from state-owned Bay Area toll bridges will fund the remaining 36.5 percent.
The legislation creating the funding mechanism for the East Span Project established the Bay Area Toll Authority (with the same board as the Metropolitan Transportation Commission) and authorized the Authority to collect the one dollar toll surcharge for eight years, issue revenue bonds, and allocate revenues to toll bridge projects, including the East Span Project. The Authority may also choose to extend the one dollar toll surcharge for an additional two years beyond the eight years to fund the inclusion of specified amenities. Extension of the toll surcharge for two years is anticipated to generate $230 million. Amenities specified in the funds outlined in Section 188.10 of the CSHC include cable suspension design options for the main span, provision of a bicycle facility, and funding for Transbay Transit Terminal improvements. Assembly Bill 2038, recently approved by the legislature, extends the period for the toll surcharge in order to fund a pedestrian/bicycle path on the SFOBB West Span. This results in $1.5 billion potential construction budget for the SFOBB East Span Project.
The total base budget of $1.3 billion includes an allocation of $100 million for a cable-supported structure. The type of cable-supported structure is not specified in the CSHC. The design options presented in Section 2.3 include cable-supported structures. Funding of a cable-supported system costing more than $100 million would require the Authority to extend the one dollar toll surcharge beyond the initial eight-year period.
Cable-supported design variations are included in the East Span Project description of replacement alternatives. Potential impacts of these design options are addressed in this document.
Estimated total costs for each of the alternatives identified above are listed in Table 2.4-1. Comparative life-cycle costs are presented in Table 2.4-2. The cost estimates are conceptual and are based on available information about the existing East Span, new proposed alignments, existing utilities, and various local supplier and contractors’ quotations.
The project costs range from zero for the No-Build Alternative to $1.65 billion for Alternative N-6, suspension design option. No-Build Alternative costs do not include the $19 million interim retrofit improvements that are currently under way. The estimated construction cost of the Retrofit Existing Structure Alternative is $0.9 billion.
Based on a comparative cost study, prepared by Caltrans in 1996, it is estimated that the maintenance costs for the retrofit alternative would be $44 million over the projected 50-year life span of the structure. Life-cycle costs of replacement alternatives have not been developed for the projected 150-year life spans of the structures. A comparison of selected maintenance operations and repairs of the first 60 years of service indicated that differences among replacement alternatives are small (see Table 2.4-2). Comparing the life-cycle costs of the replacement structure to the maintenance costs of the retrofit structure means that a new bridge, which would last 100 years longer, would be less expensive to maintain over the long term.
Table 2.4-1 Cost Estimate Summary
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Alternative |
Retrofit Existing Structure |
Skyway ($ billion) |
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| Dismantle Existing East Span |
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| Pedestrian / Bicycle Path |
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| Aesthetic Lighting |
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