Effie Milionis, a spokeswoman for the Dumbarton Bridge Seismic Safety Project, said that during the three-day closure Caltrans will replace a major expansion joint on the western side of the bridge across six lanes of traffic.
The bridge will be closed from 10 p.m. Friday, May 25, to as late as 5 a.m. Tuesday, May 29, she said.
During the closure, motorists are encouraged to take public transit or use alternate driving routes.
Motorists should allow extra time for travel and use other bridges, including state highways 237 and 92 via the San Mateo-Hayward Bridge, she said.
The closure over Memorial Day weekend will be the first time the Dumbarton Bridge will be closed for a full weekend for seismic-safety work, Milionis said.
Seismic-retrofit work began in the fall of 2010 and is scheduled to be completed early next year, she said.
Until now, crews have been working underneath the bridge's deck and their work hasn't affected traffic.
The Dumbarton Bridge is 1.6 miles long and connects the cities of Menlo Park in the west and Fremont in the east. About 60,000 vehicles cross the bridge every day.
The existing structure opened in 1982, replacing the bridge that was completed in 1927.
Visit dumbartonbridgeinfo.org for more information.