SAN RAFAEL (KPIX 5) — Caltrans is now putting the finishing touches on a project to fix 31 expansion joints on the upper deck of the Richmond-San Rafael Bridge.

Work crews have been working overnight shifts since March with jackhammers and blowtorches to demolish the existing joints, then pour concrete to build and install the replacement joints.

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“The last joint has been put in place,” said Bart Ney, a Caltrans spokesman. “And while we were working on these joints, we had to have steel plates that motorists drove over. They felt the bumps and it slowed traffic down. That is done.”

The work comes as a result of an incident back on February 7. An expansion joint broke apart, sending chunks of concrete down onto cars on the lower deck below. Nobody was hurt, but there was an all-day traffic jam. Caltrans engineers later inspected more joints and found several others had wear and tear. So they decided to replace all 61 joints, which were built back in the ’50s.

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This project on the westbound lanes will wrap up in the next few weeks after placing special rubberized seals designed to shrink and expand with changing temperatures are placed into the joints.

“When the bridge gets hot, it expands,” Ney said. “When the bridge cools off, it contracts. And it separates, so there’s potentially an opening. What these seals do is they rubberize it so they take up that differential. So when your car drives over it, your tires don’t feel it.“

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Later this year, Caltrans will begin a new project on the lower deck to replace 30 more expansion joints