$313M seismic retrofit of San Francisco's Transbay Tube underway
- This week, the San Francisco Chronicle reported that construction crews started a more than three-year, $313-million seismic retrofit of the Bay Area Rapid Transit’s Transbay Tube, the 3.6-mile transit tunnel that runs 135 feet under the San Francisco Bay, connecting the California cities of San Francisco and Oakland.
- The retrofit entails attaching, welding and grouting steel plates along the tube’s concrete inner surface in order to create a liner. The tube system’s gallery walls will also be fitted with flat steel plates. In addition, crews will waterproof the tunnel’s concrete floors — removing and reinstalling small sections of track at a time — and then install a new pumping system.
- The tunnel structure as it is now is vulnerable to earthquakes of an 8.0 magnitude or above, and the retrofit will give those in the tube during such an earthquake time to get out before it floods.
Commuters may be inconvenienced by the schedule while the tube retrofit is taking place, but that’s nothing compared to the inconvenience of a total failure.
That is the scenario that has transportation officials in New York and New Jersey on edge when it comes to the Hudson River tunnel. The tunnel carries approximately 200,000 commuters between the two states each day, but the system’s infrastructure took a big hit when it was flooded by Superstorm Sandy in 2012, and the aging tunnel, which travels under the Hudson River, is in a state of disrepair, primarily from saltwater intrusion.
Commuters already have to deal with periodic delays as maintenance crews make constant regular repairs, but a shutdown of even one of the tunnel’s two tubes could play havoc with transportation along the entire Northeast Corridor and cost $100 million a day in economic losses. Amtrak owns and operates the tunnel and says it has another 10 to 15 years of useful life, but another flooding event could shorten that estimate.
Currently, New York and New Jersey officials are negotiating with the federal government in the hopes of getting it to pay for half of the $13 billion project’s price tag but have so far encountered resistance from President Donald Trump’s administration, which has refused to honor a deal that officials said they struck with President Barack Obama and his Department of Transportation.
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