The exact closure time Friday night will be set in the next week or two, said Effie Milionis, a spokesperson for the Dumbarton Bridge Seismic Safety Project.
The closure will allow Caltrans crews to replace the existing expansion joint on the eastern side of the bridge with a new seismic joint that will absorb and dissipate energy in a seismic event, according to an informational fact sheet. The joint spans across all six lanes of traffic, which is why the entire bridge must be closed.
Motorists are advised to allow extra time to use alternate routes or public transit.
Visit dumbartonbridgeinfo.org for alternative routes and more information.