Caltrans Finds Problems With Seismic Joint On Carquinez Bridge
VALLEJO (CBS SF) — Caltrans inspectors last month found a damaged seismic expansion joint showing signs of premature wear on the westbound side of the Carquinez Bridge, agency officials said Thursday.
During an inspection of the suspension bridge on May 15, inspectors saw that that one of its expansion joints was cracked and misaligned and that one of the 90 pivot pins holding it in place had slipped loose from its bearing, according to Caltrans spokesman Bob Haus.
When the pivot pin came loose, it damaged other components of the seismic joint in the process, including a neoprene stirrup bearing and two plate bearings, Haus said.
The spokesman said inspectors first noticed that the joint was “slightly misaligned” during an inspection in September 2012, but thought the misalignment might be repaired as part of a longer-term bridge upgrade.
But after seeing the damage to the joint in May, Caltrans crews made temporary repairs to shore it up and ensure it is fully operational, Haus said.
“There’s no danger to the traveling public at all,” he said.
Haus said Caltrans is working on plans to repair the joint and adjoining components damaged by the loosened pivot pin. He said he did not have an estimate for the repair project but said it would likely cost hundreds of thousands of dollars.
The seismic joint affected is one of two expansion joints on the westbound span of the Carquinez Bridge, also known as the Al Zampa Memorial Bridge, which opened in 2003 after a $500 million construction project and connects Vallejo to Crockett.
The accordion-like component is designed to absorb movement and includes pivot pins meant to give the bridge the flexibility it needs to stay intact both during everyday traffic and in the event of an earthquake.
The damaged joint is located along a slow lane of traffic—the part of the bridge that is most heavily traveled by large trucks.
“All signs point to this area being affected by truck traffic and we know that trucks place greater stress on transportation infrastructure,” said John Goodwin of the Metropolitan Transportation Commission, which discussed the seismic joint problem at a meeting on Wednesday.
When the Carquinez Bridge’s new span was built over a decade ago, its joint system was projected to last for about 20 years before needing to be replaced, Goodwin said.
“Now we’re at 11.5 years after opening,” he said.
The expansion joint was manufactured in Germany and supplied by the D.S. Brown Company, as were the seismic joints used on the skyway portion of the Bay Bridge’s new eastern span and on the Benicia-Martinez Bridge, according to Caltrans.
Goodwin said that while the seismic joints on the three bridges come from the same manufacturer and supplier, they have different components and “are not identical.”
Caltrans inspectors have not found any issues with the seismic joints on either the Benicia-Martinez Bridge or the eastern span of the Bay Bridge, according to Haus.
© Copyright 2014 by CBS San Francisco and Bay City News Service. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.