California transport authority Caltrans has announced the final stage of foundation demolition on San Francisco’s old Bay Bridge has got underway.
Much of the 1930s bridge has been dismantled but demolition strategies for the mass concrete elements of the foundations on the east span have taken several years to be developed.
Concrete caisson foundations in the central span were removed at the start of the year. Current demolition work is focused on removing the mass concrete pile caps that sit on timber piles in the eastern span. The demolition is aiming to remove the concrete to a depth of 1m below the mudline.
According to Caltrans the timber piles used are up to 450mm in diameter and range in length from 26 to 36m with over 600 piles supporting some of the pile caps.
The 13 remaining marine foundations are being removed with a series of implosions which started this week with others scheduled every other week until mid-November.