Bye, Bye Old Bay Bridge! Removal Process Gets A Boost

On Saturday, crews will begin demolishing the remaining 13 marine foundations of the old eastern span of the Bay Bridge and plan to finish that work by the second weekend in November, Caltrans officials said Wednesday.

"We are shortening our long goodbye to the old Bay Bridge" by finishing the work one year ahead of schedule and saving taxpayers more than $10 million, Caltrans chief deputy district director Dan McElhinney said at a
news conference Wednesday morning near the eastern end of the old span.

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,
McElhinney said.

On many weekends, up to three piers are being removed at a time to save money instead of demolishing them one at a time, according to Caltrans.

Brian Maroney, Caltrans' chief Bay Bridge engineer, said the period from early September through November is the best time to do the implosions because that's when the smallest number of fish and marine mammals
are present in the area.

"We are not blowing up the piers but instead are doing controlled implosions of structures that are mostly empty by using relatively small charges," Maroney said.

McElhinney said the impact to water quality, marine mammals and fish will be monitored before, during and after the implosions.

He said brief impacts to water quality are expected but turbidity is expected to dissipate in just over an hour.
Maroney 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.

He said the implosions will take place near "slack tide," the time when tidal fluctuation is at a balance point between ebb and flow to help minimize potential impacts to the environment by maximizing the effectiveness
of the blast attenuation system.

Caltrans plans to implode piers 7 and 8 between 10:45 a.m. and 11:45 a.m. Saturday 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.

He said the alternate times are one-hour windows at about 11:30 a.m. Sunday and noon on Monday.

McElhinney said Caltrans officials will close the new eastern span of the Bay Bridge on a rolling basis of 20 to 30 minutes to protect motorists, pedestrians and bicyclists.

Maroney said the controlled charges will happen underwater and motorists won't see them but they might hear them and be distracted.

According to McElhinney, the 2-mile pedestrian/bicycle path on the new eastern span will be closed for safety and security reasons the week before each implosion, so that path is now closed in advance of the implosions scheduled for Saturday.

Maroney said that as a safety precaution, during the implosions BART will briefly pause trains that go through its Transbay Tube.

However, he said studies done during previous implosions showed that the tube only moved the same amount it moves each time a BART train passes through.

— By Bay City News Service / Image via Shutterstock