If Seattle isn’t serious about replacing the quake-damaged Alaskan Way viaduct, how serious should the rest of Washington be about it?
Next year will bring the 10th anniversary of the Nisqually earthquake and the 10th anniversary of the engineering report that the viaduct had to be rebuilt or replaced – lest it collapse in the next big shake.
Despite nearly a decade of facing what some would consider a dire threat, Seattleites seem poised for yet another Big Dither.
Our strong collaborative instincts here in the Pacific NW also make it hard to rapid arrive at a solution. Maybe that is good but sometimes you may have to move fast.
The Alaskan Way Viaduct is built similarly to the Cypress Street Viaduct that collapsed in Oakland during the Loma Prieta Earthquake in 1989. During the NIiqually Earthquake in 2001, the Viaduct was damaged and the need for it to be replaced was recognized.
As I was in a building in downtown seattle at the time of the quake, I have some personal views on this. The Alaskan Way Viaduct is built on fill, which can liquify during a strong enough quake, bringing down a thoroughfare that carries about 110,000 vehicles a day. There is a degrading sea wall that helps stabile everything.
Here is a simulation of what would happen if the Nisqualy quake had lasted 60 seconds instead of 40, had been 20 miles away instead of 30 or was a magnitude 7.0 quake instead of a 6.8:
This simulation is actually at the corner where I used to work. The building is right next to the Viaduct, just out of sight on the right. When the earthquake hit, I was in my office on the third floor on the south side. I looked down the hallway looking East and could see the floor ripple. Fortunately, the building had been retrofitted – retrofitting that was required – against quakes and stood.
Luckily for us, the quake did not last long enough to structurally damage the building. But the Viaduct needs to be fixed before another big quake.
But Seattle has been working on finding new options since 2001 and seems to have finally settled on a tunnel for the traffic rather than rebuilding the entire viaduct above ground. The state is on board and money will be available.
However, in the typical fashion seen when herding cats, a few people have decided to try and stop this process by using citizen initiatives to force a change.
So we shall see what happens.