Study the Retrofit? We Already Have
Nick Licata, David Sucher, and others have argued that the Washington Department of Transportation (WSDOT) should consider retrofitting the existing Alaskan Way Viaduct to withstand a major earthquake, rather than digging a tunnel, building a new viaduct, or simply tearing it down. Their complaints have prompted the DOT to agree to spend eight weeks studying a proposal by two retired engineers, Neil Twelker and Victor Gray, to brace the viaduct with a system of steel beams, shock dampers, and angular supports.
This sort of thing is exactly why we’ve been talking about the viaduct for five years instead of doing anything about it. WSDOT, after all, has already been down this path once before, in 2001, when its consultants concluded that the retrofit proposed by Gray and Twelker would not protect the viaduct in an earthquake. Nor would it address the eroding seawall, which also needs to be replaced. A retrofit, the study concluded, “may be effective in keeping certain sections of the viaduct intact [in an earthquake] but it will not serve the purpose of making the structure safe overall.”
In addition, the report continued, the retired engineers’ cost estimates - they now claim a retrofit could be done for $800 million, compared with $2 billion for the cheapest rebuild alternative - were “oversimplified” and “too low.” For example, the engineers estimated that jet grouting in the soil underneath the viaduct (basically turning the soft, liquifiable soil into concrete) would cost just $700,000, a figure WSDOT said ignored “the extra costs of working in difficult conditions, around and over traffic, challenging construction techniques and other peculiarities of the project.”
Then, in 2003, another study concluded that retrofitting the viaduct would be both less safe and only slightly less expensive than rebuilding it. Meanwhile, “after” renderings of the viaduct provided by Licata’s office showed a nearly solid box of concrete, with pillars twice as large as the current structure’s.
Hi Erica,
Perhaps you could give readers the key link:
'You can't get there from here.'.
It's not so much that I think that the Retrofit is the cat's meow or that I believe that the Viaduct is ideal. (My own opinion is actually fairly irrelevant.)
What I am trying to get across is that the Retrofit is politically inevitable and we might as well all get real about it. I do not believe that there is a great deal of choice once you start thinking through the money avaiulable and the real world scenarios. Please go back and read my link. I may very well be wrong but no one so far has explained the errors of my logic. Have at it.
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As to WSDOT's conclusions, why is such a usually skeptical journalist i.e. you, now such an advocate for them? So fervently supporting WSDOT? You accept its views that a Retrofit wouldn't work. Yet you don't accept the Gray/Twelker claim that a Retrofit will work. Do you have the technical background to be able to judge the competing claims & assertions?
I know I don't have that ability.
But I do know that Gray and Twelker and others are very well-respected engineeers. So why not listen to them carefully?