Bridge repairs taking longer than expected

October 14, 2010 5:39:11 PM PDT
A cracked steel beam on the San Mateo Bridge is taking longer to fix than Caltrans first predicted. Commuters will have to wait until Friday for the westbound lane to reopen. The source of the problem is a cracked wishbone Y-joint under the bridge.

On board a motor boat, reporters were able to take a closer look as Caltrans crews worked on the underside of the bridge. The damaged piece is one of a series of steel beams each in the shape of a wishbone. Each is connected to concrete girders that support the road.

Thursday afternoon Caltrans was securing steel plates above and below the beam. They were also drilling holes on each side of the 10-inch crack to make sure it does not spread.

Caltrans says there was cause for concern, but not cause for alarm.

"They say the chain is only as strong as its weakest link and when you have a link like this that is compromised, you have to take action right away," Caltrans spokesperson Bob Haus said.

The crack was found Wednesday during a safety inspection which is done twice a year.

Caltrans still does not know why the beam failed, especially because that piece was installed in 2001 as part of the seismic retrofitting project.

"It allows the bridge to move side to side three feet either way, so the bridge more or less will roll with the punches during an earthquake, so that part was compromised," Haus said.

The far-right westbound lane has been closed about 24 hours. Morning commuters knew what to expect, taking alternate routes, something they will have to do again tonight and perhaps Friday morning.

The repairs were budgeted to cost about $800,000 but Caltrans says it may cost less than that.


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