How long will we be without the Viaduct corridor?

It was with some surprise that I read a news report some months ago (Revamp may close viaduct) which stated that — contrary to first understandings — the existing Viaduct would have to be torn down at the start of any construction. (See also Boring away at tunnel advantages) If we decide to go with a tunnel, the Viaduct would have to be removed at the initiation of that construction, even though the lay person might imagine that they could operate side by side. One of the putative advantages of the tunnel was that the corridor would be open throughout the construction period. That was a general misunderstanding. The issue is something to do with construction logistics and the hiatus was supposed to be 3-4 years.

So anyway, the construction schedule for a tunnel is supposed to be something like 7-9 years. (The "facts" keep changing so it is hard to know where the truth lies.)

So it seems to me that no matter what plan we choose (except for the retrofit) we lose the total use of the corridor for far more than the 3-4 years I had suggested in a previous post. Nine years without the viaduct corridor is (to me) like thirty years — it's more-or-less a permanent condition. The logistics & time frames of this project should have a strong influence on our final decision.

Can anyone out there help me sort out the best information available? Or point to an authoritative and trustworthy source? Comments are open.

Comments

[Jesse McCann]

Based on my cursory understanding of construction techniques, I'd imagine that a substantial amount of money could be saved by closing the viaduct for more of the construction. Part of what made the Big Dig so expensive was the construction of temporary elevated highways to conduct traffic during the construction process. Even a rebuilding of the viaduct (without a tunnel) would be made much more expensive if it was decided to keep the route open during the construction process. I am not sure exactly how the WSDOT estimates the costs for the viaduct replacement alternatives while saying that traffic closures are still up in the air.

I think we're in a position where any reconstruction (excluding retrofitting) will involve multi-year closure of the viaduct. If the viaduct is necessary, how can the city's economy survive ten years without it? Wouldn't the city adapt to its absence, for better or for worse?