Heading to San Francisco this weekend? You'll need to take a different route or avoid going all together.

That's because the Bay Bridge was closed down to all traffic Friday night and will stay closed in both directions through 5 a.m. Tuesday.

The closure will allow Caltrans to perform seismic safety work on a section of the bridge east of Yerba Buena Island Tunnel. The work will impact traffic coming and going to and from San Francisco and Oakland over the long Labor Day holiday weekend.

Pleasanton residents traveling to San Francisco can take the following alternative routes: the San Mateo Bridge (Hwy. 92) or the Dumbarton Bridge (Hwy. 84). Those taking detours should expect regional traffic delays. BART has added trains during the weekend. Check www.511.org for further information and/or updates.

For a fact sheet on the closure, click on the following link http://www.baybridgeinfo.org/Editor/assets/ybi_laborday0nline.pdf