Caltrans: rumble strips not damaging Bay Bridge

Caltrans is reassuring Bay Bridge commuters that the rumble strips are not causing damage to the span.

May 25, 2010 7:06:28 PM PDT
An East Bay engineer claims that the rumble strips Caltrans recently installed on the Bay Bridge S-curve are just not safe, but Caltrans disagrees.

"I was horrified. My reaction is horrified," said Professor Hassan Astaneh, who says he first noticed the strips this past weekend on a trip to the San Francisco International Airport.

The four-strip sets have been placed just ahead of the S-curve on the bridge decks, the same area where a truck driver lost control and plunged to his death last year.

According to Caltrans, the goal is to alert motorists to a change in the roadway at the S-curve, but Astaneh says the effort to solve one problem is causing another. "This is the last place you want to put rumble strips, because rumble strips cause very serious vibration," said Astaneh.

Astaneh says the vibrations could lead to another failure like last September, when wind vibrations were blamed for a crack in an eyebar, or key support beam of the bridge. The piece was repaired, but only after the bridge was closed for several days.

"The important thing is trucks, he said. "These heavy trucks, when they hit the rumble strip, they create a very large impact on the roadway."

But Caltrans spokesman Bart Ney told ABC7, their engineers have determined the rumble strips cause only minimal vibration and pose no threat to the structural integrity of the 70-year-old bridge.

"There's nothing about the rumble strips that cause any type of damage to the east span of the Bay Bridge," he said. "The addition of a 3/8 of an inch doesn't cause any measurable short-term fatigue. And the lifespan of the east span is approximately five to six years before we have the new bridge in service."


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