Underwater Bay Bridge demolition begins

Demolition of the remaining 13 marine foundations of the bridge’s old eastern span is scheduled to begin today, Caltrans officials said.

The controlled charges will happen underwater and motorists won’t see them, according to Caltrans chief deputy district director Dan McElhinney.

The 2-mile pedestrian/bicycle path on the new eastern span is already closed in advance of the implosions scheduled for today.

Caltrans plans to finish the work by the second weekend in November, according to McElhinney. Caltrans began demolishing the old eastern span in September 2013 after the new eastern span opened to traffic.

Pier E3, which was the largest pier and the closest to Yerba Buena and Treasure islands, was removed in 2015 and piers E4 and E5 were removed in 2016.

Piers 7 and 8, which are to the east of the piers that were previously removed, will be removed this weekend and the remaining piers will be removed every other weekend through the second week in November, officials said.

Brian Maroney, Caltrans’ chief Bay Bridge engineer, said Caltrans will use a blast attenuation system, also known as a “bubble curtain,” to minimize impacts to biological resources in the Bay on each foundation-blasting project.

Caltrans plans to implode piers 7 and 8 between 10:45 a.m. and 11:45 a.m. today, but the implosions could be postponed at the last minute if mammals such as the harbor porpoise or the Pacific harbor seal come within a half-mile of the implosion areas, McElhinney said.