SAN FRANCISCO - The Latest on falling concrete that shut down a San Francisco Bay Area bridge (all times local):

9 p.m.

Authorities have reopened all lanes of a major San Francisco Bay Area bridge that was closed for hours when concrete chunks fell onto a roadway.

The California Department of Transportation says the Interstate 580 Richmond-San Rafael Bridge was shortly after 11 a.m. Thursday when concrete chunks — some larger than a baseball — fell from the westbound upper deck onto the eastbound lower deck.

At least one car was struck and heavily damaged but no injuries were reported.

The shutdown lasted hours, except for one brief partial afternoon reopening before more concrete fell. The final eastbound lanes were reopened Thursday night.

The bridge carries tens of thousands of cars daily.

While contractors have been working on the upper deck, Caltrans says it hasn't determined what caused the concrete to fall.

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8 p.m.

Authorities have reopened all westbound lanes of a major San Francisco Bay Area bridge that was closed when concrete chunks fell onto a roadway.

Two eastbound lanes are open as well and crews are working to reopen the rest.

The California Department of Transportation says the Interstate 580 Richmond-San Rafael Bridge was shortly after 11 a.m. Thursday when concrete chunks — some larger than a baseball — fell from the westbound upper deck onto the eastbound lower deck.

At least one car was struck and heavily damaged but no injuries were reported.

The shutdown lasted hours, except for one brief partial afternoon reopening before more concrete fell.

The bridge carries tens of thousands of cars daily.

While contractors have been working on the upper deck, Caltrans says it hasn't determined what caused the concrete to fall.

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6:30 p.m.

Authorities have reopened one eastbound lane of a San Francisco Bay Area bridge that was closed when concrete chunks fell onto a roadway.

The California Department of Transportation says the Interstate 580 Richmond-San Rafael Bridge was closed shortly after 11 a.m. Thursday when concrete fell from the westbound upper deck onto the eastbound lower deck.

Lanes reopened later but then quickly closed again when more concrete fell.

By evening, one eastbound lane reopened but the westbound lanes are closed.

The CHP says at least one car was struck but there were no injuries.

Caltrans crews are installing metal plates on the upper decks so those lanes can reopen.

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4:27 p.m.

A major bridge in the San Francisco Bay Area has been closed after large chunks of concrete fell from the upper deck.

The San Francisco Chronicle reported that one car was damaged but no injuries were reported.

The California Highway Patrol posted an alert about the Richmond-San Rafael bridge closure shortly before noon on Thursday, saying there was no estimated time for reopening.

It was not clear what caused the concrete to fall. A CHP spokesman did not immediately return a call seeking more information.

The CHP posted photographs showing what appeared to be football-sized pieces of concrete that had fallen. The agency said it was working with Caltrans to determine the problem and find a solution.

The closure was expected to cause heavy traffic.

News from © The Associated Press, 2019