The recent devastating quake in Japan was a chilling reminder for a lot of San Franciscans that another big one could hit the Bay Area at any moment. Quite possibly the scariest place to be during a quake is trapped in a subway tunnel. Get on the J at the wrong minute and an unlucky passenger could be stuck there for hours…or worse. It would be nice to know how two of Muni’s oldest tunnels, the 82-year old Sunset Tunnel and the 94-year old Twin Peaks Tunnel, would fare in an earthquake. However, according to an internal Muni document uncovered by the Examiner, the tunnels have never undergone seismic testing and are in desperate need of significant repair work.
The 2009 report, put out by the SFMTA’s Capital Programs and Construction Division, asserts both of the tunnels are in good condition considering they were built nearly a century ago and say that extensive wear and tear from near constant use is to be expected. Still, the report noted some rather unnerving defects:
“[In the Twin Peaks Tunnel] corroded steel beams surrounded by loose pieces of concrete held up the tunnel at its eastern end. A retaining wall was rotting. Further down the tunnel, corroded concrete beams and slabs were so deteriorated that inspectors said they ‘may be compromised.’ And at the tunnel’s western end, the ceiling contained “extensive cracks,” one three-quarters of an inch wide and 10 feet long.
The report recommended starting work to fix the problems immediately. However, two years later, repairs have yet to begin.
SFMTA claims it has plans to spend $1 million to solve the most urgent problems by the beginning of 2013. The other $6 million worth of recommended repairs is stalled indefinitely, they say, until the beleaguered agency can come up with the needed funds.
Even though SFMTA was the recipient of over $200 million in federal stimulus grants, that money was earmaked for new projects like fabled Central Subway and a Bus Rapid Transit (BRT) extension along Van Ness.
Over the next 20 years, Muni is facing a long-term budget deficit of $1.6 billion, so coming up with the $6 million needed for these supposedly urgent tunnel fixes may remain a pipe dream.
While this study uncovered some issues with the tunnels, it didn’t look into how they would stand up in a massive earthquake. Muni has periodically done visual inspections like this one, but visual inspections alone, say experts, aren’t enough to accurately assess a tunnel’s seismic integrity. In actuality, the tunnels’ resistance to earthquakes has never been thoroughly studied.
When BART finally did a long-overdue evaluation of their earthquake preparedness, they found over $1 billion in repairs they needed to make in order to make their system truly earthquake resistant–even though all of their tunnels did fine during the ’89 Loma Prieta quake.
It would be nice to think that Muni will find enough money for both the needed repairs and an in-depth earthquake preparedness study. If the cost remains prohibitive, riders will just have to hope that the next big one hits when they’re in the open air.
Photo of “Rotted wood lagging at ramp retaining wall near Eureka Portal”: SFMTA
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