The affected bolts anchor shear keys and bearings that are sandwiched between the bridge decks and piers and are designed to restrain the bridge decks during a large seismic event.
Diagram of proposed bolt/rod fix, showing cable and saddle system to secure the shear keys to the beam.
Dr. Brian Maroney, Caltrans' lead bridge engineer, holds up a piece of a three-inch diameter bolt at a post-BATA meeting press briefing.
August 15, 2013 UPDATE
The state Toll Bridge Program Oversight Committee (TBPOC) today gave a green light to an interim fix to the seismic system on the new Bay Bridge East Span, and determined that the new East Span will open to traffic by 5 a.m. on Tuesday, September 3, 2013, following a five-day bridge closure that will begin the evening of Wednesday, August 28. Visit BayBridgeInfo.org for updates on the closure.
August 13, 2013 UPDATE
The Toll Bridge Program Oversight Committee (TBPOC) today set a meeting for Thursday, August 15, 2013, starting at 10 a.m. to discuss a series of new reports on East Span bolt issues and plans for opening the new span to traffic. View the reports and a press release, "Independent Experts Recommend Interim Bay Bridge Fix."
July 10, 2013 UPDATE
At a special meeting today of the Bay Area Toll Authority (BATA), members of the Toll Bridge Program Oversight Committee (TBPOC) briefed BATA commissioners on findings contained in the recently released report on the high-strength steel bolts used on the new Bay Bridge East Span. A key focus was the ongoing effort to retrofit an area of the bridge — a crossbeam known as E2 — where bolts securing seismic gear had previously failed. The fabrication and installation of reinforcing steel saddles is on track to be done by December 10, 2013, with the cost now estimated to be $20 million.
Frieder Seible, a member of Caltrans’ Seismic Safety Peer Review Panel, provided a graphic showing the superior seismic strength of the new East Span design compared to the old East Span, and presented a proposal for an interim fix to the seismic gear at E2 that could move up the opening date for the new East Span.
July 8, 2013 UPDATE
The Toll Bridge Program Oversight Committee (TBPOC) announced today that the previously scheduled 2013 Labor Day weekend opening of the new East Span of the San Francisco-Oakland Bay Bridge has been postponed. TBPOC also released its investigative report looking into the 32 bolts that broke on the new East Span in March 2013 and a review of other bolts on the span, along with a series of technical appendices. These materials wil be discussed at a special meeting of the Bay Area Toll Authority on Wednesday, July 10, 2013, that is scheduled to start at 10 a.m. and will be webcast.
June 24, 2013 UPDATE A major briefing on the status of Bay Bridge East Span bolt issues and prospects for opening the new bridge is set for a meeting of the Bay Area Toll Authority on Wednesday, July 10, 2013. See the agenda and listen to the webcast at http://mtc.ca.gov/meetings/schedule/.
June 14, 2013 UPDATE
Members of the Bay Area's legislative delegation this month asked the Toll Bridge Program Oversight Committee (TBPOC) for information about financial incentives established for contractors working on the new Bay Bridge East Span to meet select project milestones by specified deadlines. The TBPOC, in a June 14 letter to legislators, detailed a package of incentives approved in September 2010 for a joint venture between American Bridge Co. and Fluor Corp. related to its work on the self-anchored suspension (SAS) portion of the new East Span, and for MCM Construction related to its work on Yerba Buena Island Transition Structure.
May 29, 2013 UPDATE
The Toll Bridge Program Oversight Committee (TBPOC), which is made up of the chiefs from the Bay Area Toll Authority (BATA), Caltrans and the California Transportation Commission, today briefed BATA's commissioners on the status of efforts to engineer and construct a solution to problem bolts on the Bay Bridge East Span. Work is underway preparing the concrete cap beam for the retrofit, and the saddle design is nearing finalization. Material to construct the fix is being procured. The retrofit completion schedule and a report on the condition of other bridge bolts will be presented at the July 10, 2013, BATA Oversight meeting.
May 24, 2013 UPDATE Crews have begun prep work for the saddle fix to the broken bolts on the new Bay Bridge East Span, including chipping of concrete and drilling holes at the site of the bolt problem — a concrete cap beam that sits underneath the decks at the eastern edge of the self-anchored suspension span. See photos here.
May 22, 2013 UPDATE
The Bay Area Toll Authority will be briefed on the Bay Bridge East Span bolt problem and other issues at a special meeting set for Wednesday, May 29, 2013, starting at 1 p.m. at the MetroCenter Auditorium.
May 15, 2013 UPDATE
California Senate Transportation and Housing Committee hearing, with an update on the Bay Bridge East Span bolt issue, May 14, 2013.
May 8, 2013, UPDATE
The Toll Bridge Program Oversight Committee (TBPOC), which is made up of the chiefs from the Bay Area Toll Authority (BATA), Caltrans and the California Transportation Commission, today recommended a fix for the bolt issue affecting the new East Span of the San Francisco-Oakland Bay Bridge. The recommendation is contained in a presentation to the BATA Oversight Committee. TBPOC also released a letter to the California Division of the Federal Highway Administration (FHWA) asking their team to “provide an arms-length review” of TBPOC’s analysis and strategy for rectifying the bolt problem. Also released today is a report containing a metallurgical analysis of the broken anchor rods. A special BATA meeting has been set for May 29, 2013, to address the bolt issue.
April 24, 2013 UPDATE The Toll Bridge Program Oversight Committee today provided the Bay Area Toll Authority (BATA) with an update on the status of the East Span bolt issue. The presentation can be viewed to the right.
April 10, 2013 Commissioners of the Bay Area Toll Authority (BATA) were briefed today on the effort to diagnose and repair steel rods — referred to as bolts — used in the construction of the new East Span of the San Francisco-Oakland Bay Bridge. The briefing took place at the regular monthly meeting of the BATA Oversight Committee. An update on the repair effort was provided by representatives of the Toll Bridge Program Oversight Committee (TBPOC), which is overseeing the East Span project and is made up of three agencies: BATA, the state Department of Transportation (Caltrans) and the California Transportation Commission (CTC).
Three inches in diameter and measuring from 9 feet to 24 feet in length, the steel bolts anchor seismic shear keys and bearings to a concrete beam located at the eastern end of the East Span’s signature self-anchored suspension span (referred to as the SAS). The beam in turn caps vertical piers that reach up from the water and help to support the span’s twin decks.
Problems with some of the bolts first surfaced in early March 2013 once the weight of the twin decks was transferred to the SAS’ cable suspension system, and crews began the process of tightening the rods. Engineers are continuing to diagnose the cause and developing a repair plan. Materials from today’s meeting and a prior BATA meeting are posted to the right. Updates will be provided to BATA on a regular basis. Agendas will be posted here.
San Francisco-Oakland Bay Bridge Seismic Retrofit Project, Independent Review of Analysis and Strategy to Shim Bearings at Pier E2 to Achieve Seismic Design Requirements - Submitted by Modjeski and Masters, Inc., August 9, 2013