The Washington State Department of Transportation posted new information today about newly discovered damage to the 61-year-old, double-decker Alaskan Way Viaduct. And meanwhile Mike Lindblom—love that guy—at the Seattle Times reports on growing cracks in the concrete:
Inspections on the Alaskan Way Viaduct on March 1 found new cracks forming near Seneca Street, and some existing cracks have lengthened, according to state highway engineers....
Tom Baker, WSDOT bridge engineer, said the most likely cause for cracking is the 2001 Nisqually Earthquake, which he said weakened the underground foundations in ways that aren’t fully understood. Cracks have recently spread on vertical columns, as well as the horizontal girders that support the road deck, he said.
The viaduct has been sinking and cracking a lot since since the Nisqually earthquake in 2001. One part of the central viaduct has sunk five inches since then. Here's a photo from 2007 of cracks in the upper deck. In 2008, former governor Chris Gregoire said she would tear down the central portion of the viaduct by 2012—the part that's still standing—because, as former county executive Ron Sims put it, "It's not safe." The Seattle Times reported portions of the viaduct have a 9-out-of-100 safety rating. In 2009, the state issued an alarming video that depicts the viaduct collapsing into a flame-engulfed waterfront:
- This was the state's own depiction—in 2009—of the imminent risk to the viaduct in an earthquake.
There's also the Washington State Department of Transportation's "Seismic Vulnerability Analysis Report":
The risk of an earthquake causing the Alaskan Way Viaduct to fall down is significantly higher than was previously thought. Until now, it was estimated that it would take seismic ground motions with a 210-year return period to initiate collapse of the Viaduct. In practical terms, this translates to an approximate 1-in-20 chance in the next ten years of an earthquake sufficient to cause portions of the Viaduct to collapse. We found that an earthquake capable of initiating collapse of the Viaduct has a much shorter expected return period of 108 years. This translates to approximately a 1-in-10 chance in the next ten years of an earthquake that would cause portions of the Viaduct to collapse, or roughly double the previously identified risk. This change in risk is based on new geotechnical information and a better understanding of local and regional seismic behavior.
That report was issued seven years ago. Expert faculty at the UW said we should close the viaduct within two years. They wrote that eight years ago. But we've kept the viaduct standing.
We're supposedly waiting for the deep-bore tunnel to replace the viaduct, but the tunnel is being delayed longer and longer. First it was reportedly on time, then a couple months behind, and now the latest reports say drilling won't even resume until September, when the drilling was supposed to be mostly finished. Based on its track record: We cannot trust the state to give us straight answers, to finish the tunnel on time, or tear down the viaduct soon.
The specter of another major earthquake, however, is always present. That is why we are determined to replace the Alaskan Way Viaduct before Mother Nature makes the decision for us.
Mother Nature isn't going to wait for our endless delays. She doesn't give a shit about our cursed tunnel megaproject. Close the viaduct—it was supposed to happen years ago—and deal with the traffic. It's not worth it.