Bridge over 405 connecting Costa Mesa and Irvine to close for repairs for 4 months

A bridge over the 405 Freeway that links Costa Mesa and Irvine will be shut down soon for four months of repairs to stabilize the embankment under one of the approach ramps.

The California Department of Transportation plans to close Red Hill Avenue to all traffic between Pullman Street in Costa Mesa and Main Street in Irvine starting at 9 p.m. Aug. 29. The bridge is part of that stretch.

The roadway is expected to remain closed until Dec. 30, according to Caltrans spokesman David Richardson.

On Friday, workers and heavy machinery could be seen operating on the Costa Mesa side of the bridge. An electronic message board had been set up to notify drivers of the coming closure.

The closure is necessary because the earth under the approach ramp on the Costa Mesa side is moving, which has caused walls meant to keep the soil in place to bulge slightly and “triggered progressive pavement cracks on the roadway above,” according to Caltrans.

It’s not yet certain what caused the soil to move to the extent it has, Richardson said.

As part of the $9.5-million project, the underlying soil embankment will be reinforced and new retaining walls will be constructed.

“We’re going to buttress the heck out of it so this won’t happen again,” Richardson said.

The entire cost is being funded through the State Highway Operation and Protection Program, Richardson said.

The closure of the bridge, which sits between John Wayne Airport and the junction of the 405 and 55 freeways, could lead to additional traffic on nearby streets such as Paularino Avenue and MacArthur Boulevard.

“For most big closures we have, it takes about three, four days for people to figure out what their best route is, and that’s what they use,” Richardson said.

“We’re going to have changeable message signs and portable message signs in place for the closure,” he added. “We monitor every closure we have.”

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Luke Money, [email protected]

Twitter: @LukeMMoney