San Francisco-Oakland Bay Bridge Demolition

All Images Courtesy of Caltrans

Client:

California Engineering Contractors
Completion Date:

March 2017
Key Collaborators:

Silverado Contractors
Project Type:

Marine Infrastructure
Service Categories:

Naval Architecture

Owner Services & Onsite Support

Marine Consulting
Challenge:

Develop an efficient demolition method that was both safe and environmentally friendly.

Demolishing the Bridge, Protecting the Bay.

The Bay Bridge crosses from San Francisco to Oakland and carries about 260,000 cars per day. After a portion of the east span collapsed in the 1989 Loma Prieta earthquake, it was apparent that the bridge’s lack of seismic resiliency was going to be a problem, and replacement and retrofit efforts began. Once the new bridge was constructed, the old one had to be disassembled. The challenge was to develop an efficient demolition method that was both safe and environmentally friendly.

A BARGE-BASED SOLUTION.

Glosten stepped in to assist California Engineering Contractors with the marine aspects of the demolition. The method involved reversing the construction process by disassembling the bridge in sections: lowering 504-foot bridge spans onto barges using strand jacks, and lifting 288-foot bridge spans off the piers and onto barges using self-elevating towers. The barges then transported the structures dockside to be demolished and recycled. Glosten assisted in selecting the barges capable of the job, determined how to safely configure them, designed the span support structure, and analyzed the stability of the barges during loadout, transport, and dismantling. Additionally, the project team determined wind/current conditions, towing configuration and limitations, and mooring design to maintain the vessel position during span lowering. Glosten also provided on-site support for the lift off and/or lowering of bridge spans.

The demolition was completed eight months ahead of schedule. The team succeeded in lowering the 504-foot spans at a rate of one per month, and the 288-foot spans at a rate of two spans per month. In the end, a challenging engineering feat was accomplished with respect paid to the safety and environmental concerns set forth in the contract. The Bay Bridge will now be seismically resilient for many years to come.