CORRIDOR OVERVIEW

We have not forgotten the lessons learned from the Loma Prieta earthquake, or that the clock is always ticking. When a 250-ton section of the upper deck of the East Span collapsed during the 7.1-magnitude earthquake, it was a wake-up call for the entire Bay Area, as the bridge closed temporarily for repairs. While the East Span quickly reopened within a month, critical questions lingered: how could the Bay Bridge—an important regional lifeline structure—be strengthened to withstand the next major earthquake? Should the bridge be rebuilt, repaired or both? These were critical decisions to ensuring that the Bay Bridge would survive heavy seismic activity and provide access for emergency services and rebuilding efforts following a major earthquake.

After seismic experts from around the world performed an exhaustive study, it was determined that to make each of the separate elements seismically safe on a bridge of this size, the work must be divided into numerous projects, each presenting unique challenges. Yet each component needed to contend with one common challenge — the more than 280,000 vehicles that cross the bridge each day.

Keeping traffic flowing on one of the nation's busiest bridges in the midst of this work demands new levels of innovation, from extremely complex traffic shifts and the staging of crews and equipment, to unique approaches to demolition and construction. We have celebrated several milestones already—traffic is now flowing smoothly on the permanent eastbound and westbound decks of the West Approach; the 1.2-mile long Skyway—with its stunning panoramic Bay views—is now complete; and all retrofit work on the West Span (between San Francisco and Yerba Buena Island) is finished.

We're Making Your Bridge Safer

The twin suspension bridges of the West Span (near San Francisco) required extensive retrofit work. The work on the West Span, completed in 2004, involved bolstering the span with massive amounts of steel, concrete, bolts and new seismic safety technology. Work on the West Approach, a one-mile stretch of Interstate 80 in San Francisco, involved completely demolishing existing structures and building new ones, one section at a time, as traffic continued to flow. Much of this work occured within inches of residential and commercial buildings.

Rather than a seismic retrofit, the two-mile-long East Span is being completely rebuilt. When completed, the new East Span will consist of several different sections, but will appear as a single streamlined span. The new span will feature the world’s longest Self-Anchored Suspension (SAS) span, connected to an elegant roadway supported by piers (Skyway), which will gradually slope down towards the Oakland Shoreline (Oakland Touchdown).

The eastbound and westbound lanes of the East Span will no longer include upper and lower decks. The lanes will now be parallel, providing motorists with expansive views of the Bay. Those views will also be enjoyed by bicyclists and pedestrians, thanks to a new path on the south side of the bridge that will extend all the way to Yerba Buena Island. The new span will be aligned north of the existing bridge to allow traffic to continue flowing on the existing bridge as crews build the new span. A new Transition Structure on Yerba Buena Island (YBI) will connect the SAS to the YBI tunnel, and will transition the East Span’s side-by-side traffic to the upper and lower decks of the tunnel and West Span.

When construction of the new East Span is complete and vehicles have been safely rerouted to it, the original East Span will be demolished.