Sections of the 405 Freeway in the Sepulveda Pass will be closed for construction

Starting Tuesday, one of the busiest sections of the 405 Freeway will be closed for five consecutive nights so contractors can tear down the north side of the Skirball Center Drive bridge in the Sepulveda Pass.

The work, which will make room for a new carpool lane, requires several full and partial freeway closures between 9 p.m. and 6 a.m. through Saturday. Demolishing the structure will occur between midnight and 5 a.m.

Skirball is the second of three major bridges that will be rebuilt to accommodate the HOV lane. Half of the Sunset Boulevard bridge was demolished in late July. Work on the Mulholland bridge is set to begin in early 2011.

“We recommend that motorists give themselves extra time to get through the pass,” said Dave Sotero, a spokesman for the Los Angeles County Metropolitan Transportation Authority. “The closure area is about 5 1/2 miles. Depending on traffic, it could double or triple the amount of time to get through the area.”

MTA officials say the southbound 405 from Burbank Boulevard to Getty Center Drive, as well as the two northbound lanes closest to the freeway median, will be closed at 9 on Tuesday and Wednesday.

On Thursday and Friday night, the northbound 405 from Getty Center Drive to Ventura Boulevard, as well as the two southbound lanes nearest the median, will be shut down. The northbound Skirball Center Drive off-ramp will be closed on Saturday, and the northbound 405 will be reduced to three lanes.

Sotero said the closures would disrupt access to surface streets, the 405 and freeway off-ramps along one of the most heavily traveled highways in the region. According to the California Department of Transportation, motorists make about 290,000 trips a day on the 405 through the Sepulveda Pass.

To keep vehicles moving, traffic control officers will be stationed at key locations, and alternative routes will be set up, including Sepulveda Boulevard, which will be used as the primary detour. Sepulveda parallels the 405 through the closure area.

Detailed information about detours is available at https://www.metro.net/405 or by calling the project hotline at (213) 922-3665.

Rebuilding the Skirball Center Drive bridge is part of a $1-billion project to create a 10-mile carpool lane on the northbound 405 between the 10 and 101 freeways. The improvements include new ramps, seismic retrofits and sound walls.

The south side of the bridge is scheduled to be demolished and rebuilt after the north side is finished in about seven months.

dan.weikel@latimes.com