Caltrans Performing Stress Tests On Bay Bridge Rods

OAKLAND (KCBS) – Caltrans is now performing stress corrosion tests on a random sampling of rods on the eastern foundation of the Bay Bridge.

The testing of 13 rods on the Bay Bridge was prompted by early breakage of bolts made from similar materials.

“The material that snapped was grade A354 BD bolts. These are also grade A354 BD bolts,” said engineer Bill Casey. “They’re estimated from a different time period.”

Casey said the rods they are testing were made in 2010. The corrosion testing is to see how the material will perform in a marine environment, over decades and under tension.

“What we’re doing here is extremely accelerated. It takes years and decades for that kind of hydrogen to get inside the bar from stress corrosion cracking,” said Casey.

Bolt expert Bob Brignano said essentially, full-scale laboratory field tests are being done on the Caltrans property.

“We’ve built these test setups. We have a total of 13 setups we’re going to build here,” Brignano said. “Some of them will go through multiple rounds of testing. We’re doing a lot of testing.”

The testing will take months, with 23 days of testing, mimicking a decades-long corrosion process.

It’s important to note, these tests will not impact the bridge’s opening.

(Copyright 2013 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

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