San Francisco-Oakland Bay Bridge Self-Anchored Suspension Bridge Construction | California, US

The concept of constructing a bridge linking San Francisco with Oakland has existed since the early 1870s. In 1936, the longtime dream of linking the two locations was finally realized, and the nearly 5-mile-long San Francisco–Oakland Bay Bridge was officially opened to traffic.

Challenge
On October 17, 1989, a section of the eastern span of the San Francisco–Oakland Bay Bridge between Yerba Buena Island and Oakland collapsed during the Loma Prieta earthquake. American Bridge-Fluor, a joint venture between American Bridge Company and Fluor Corporation, was selected to construct the replacement of the eastern span of the bridge.

Solution
Klohn Crippen Berger, a Louis Berger affiliate, was retained by American Bridge-Fluor to provide lead construction engineering services for the project. In that role, the company:

• Designed 14 falsework piers in San Francisco Bay in anticipation of the suspension cable installation.
• Designed the lifting frame and gantry used to erect the 540-foot-high permanent main tower.

Under a separate contract, Ammann & Whitney, the long-span bridge division of Louis Berger, provided engineering services for the girder fabrication, main cable and suspension installation, and load-transfer procedure for the structure. The firm’s work included:

• Developing the cambered shape of deck girders for fabrication.
• Computing the geometry of the main cables and the lengths of the suspenders during erection.
• Preparing detailed procedures for the load-transfer of the bridge superstructure from the falsework to the suspension system.

The restored structure — designed to withstand extreme seismic and other adverse weather conditions — is the world's largest self-anchored suspension bridge.