The new San Francisco-Oakland Self-Anchored Bay Bridge (SAS) is the longest span bridge of its kind, featuring a single-tower, self-anchored suspension design with a twin orthotropic box girder deck. This iconic bridge, with its modernistic appearance, embodies the San Francisco Bay Area’s passion for innovation and aesthetics. It garnered worldwide interest during construction due to the engineering ingenuity required to overcome challenges in designing, fabricating, and erecting a single-tower bridge with a 3-dimensional cable system and sloping hangers to support the orthotropic steel deck. This design eliminated the need for massive gravity anchors, thereby minimizing the bridge’s footprint and reducing its impact on the bay water and marine life.

The SAS features a single, 4,550-foot-long cable—the longest looped suspension cable ever used for a bridge. The cable extends from the top of the tower and loops back beneath the west end, with slender suspender cables attaching the main cable to the girders beneath the roadway deck. Unlike other Bay Area suspension bridges, such as the Golden Gate Bridge, which have cables and hangers in a single (2-dimensional) plane, this design supports a unique 3-dimensional structure.

The presentation discusses the aesthetic and technological advantages of the self-anchored bridge design. Salient features of the bridge include:

Designed to withstand seismic loads expected in a 1,500-year return period.
The first suspension bridge with no direct connection between the deck and tower.
The first use of seismic energy-absorbing shear link beams in the tower of a cable-supported bridge, featuring a single continuous cable that supports the structure.
A single tower with a unique saddle design that incorporates two saddles.
State-of-the-art hinge pipe beams at the expansion joints between the SAS and adjoining bridge frames.
Special bearings and shear keys designed to resist AASHTO loads and movements.

The bridge’s silhouette resembles a harp, with its single tower composed of four legs and main cable suspenders. This design beautifully symbolizes the Bay Area’s belief in unity in diversity.