The Washington State Department of Transportation (Prevent Trans, for short) has decided to close the express lanes of I-90 to replace the expansion joints.
Based on the news generated by the expansion joints for the new Tacoma Narrows Bridge this can’t be good. And it’s not. The express lanes will be closed most of May.
This will send all the busses and car pools into the “general Purpose” lanes. Oh the humanity! Predictions are that commuters will be backed up to Snoqualmie Pass waiting for their turn to cross the bridge. My advice: retire. No way to get to work, so why try?
There are cracks in the expansion joints. They can see daylight from underneath. OK, an expansion joint is just a controlled way of managing various dimensional fluctuations of the road due to temperature, load, wind and wave stresses.
So why is it a surprise that these expansion joints expand? That’s part of the purpose, right? The other part is to make that BZZZ sound when you run over one at 60 mph. And if it expands then we should expect to see daylight. After 20 years the people that built it have probably retired or been absorbed into the Obama administration. So the new people see a “crack” and panic.
“How in the world can we put light rail on a structure with so many cracks?” is probably what they’re asking themselves.
Well, “lighten up” is my response. Sure, a little daylight seeps in from above when an expansion joint expands. It’s not a crack. That’s how it works. I spose these same people go crying to their mechanic when the little gas pump lights up on their dashboards.
Meanwhile Bellevue has been over at the Galactic Headquarters of Sound Transit begging for a tunnel. Their point is that if the light rail project goes through downtown Bellevue on the surface it will disrupt traffic. They want the line to enter a vast serpentine tunnel and emerge again on the east side of I-405.
We probably pointed this out before but I think the Tunnel Boring Machine is going to be busy digging the Alaska Way Viaduct replacement. That’s an emergency that has to be completed by 2003 in case of another earthquake. We wish them luck.
The I-90 express lane closure is a dress rehearsal for a future time when they’ll close forever due to being taken over by Sound Transit. It’s interesting that DOT is all panicked over the May closure when others are so calmly suggesting permanent closure.
Is it really the only way or do we have an alternative plan that will make everything all right? Let’s explore.
One alternative would be to build yet another floating bridge over Lake Washington. This is a real gamble since we’ve had two sink and the WSDOT is pretty sure another one is ready to sink (SR 520). We only have four in this state (Hood Canal, Evergreen Point, Mercer Island/Seattle, Seattle/Mercer Island) and a sink rate of 50%. So how are we to be confident that any new ones have better odds of survival?
Another alternative is a Lake Washington Tunnel. That’s right, dig under the lake and send the trains down there. OK, this is kind of why we decided to use floating bridges on the lake 100 years ago: it’s damn deep. This is a serious lake that goes way down and also has a deep bed of mud, silt, and dead salmon. It’s almost impossible to tunnel under because the road would have a steep down and up slope. Too steep for hybrid cars. A suspension bridge would have to span the whole lake. If we had even a wimpy earthquake the amount of offset from shore to shore would be many feet.
Nobody around Lake Washington will accept a suspension bridge that interferes with the views. They’d rather swim.
A suspension bridge could end up in the drink. Kind of the same fate as a marginal floating bridge. So why go to the trouble of building a suspension bridge if it will also sink? But doing a floating bridge on the idea that it won’t have very far to sink is also kind of goofy.
Another alternative is a ferry. We could run the light rail trains to the water and load them on barges to float across the lake. That might work except most of our ferries are also in bad shape and in danger of sinking. So do we think any new ones would be any better? And SLOW! Every other city in America would laugh at our light snail rail.
Which brings us to the last alternative because after that it gets silly. Move all that dirt from Maple Valley up and finish the Mercer Island Fill Project. Just dump dirt into the lake until there’s a nice causeway. No worries about sinking.
One small issue might be that it would take 30 years and 100 billion truck loads to do the job which would require repaving the Maple Valley Highway every six months. Much greater cost than building a whole new floating bridge.
Now you know why they want to go with the existing bridge: so far we think it floats. And what better way to get people riding light rail than taking away their precious express lanes? What a great idea.
Al
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