University Link has been officially awarded the $813 million “full funding grant agreement” from the FTA today. This is the largest New Start grant ever awarded – the previous largest was $750 million – and is 43% of U Link’s total $1.9 billion price tag. Construction on the extension is ready to begin this month, and a few demolition contracts have already been awarded.
We knew this was coming, but it still lightens the blow of today’s stimulus news. Here are some interesting engineering details from the DJC coverage on the today‘s news:
Next month, Sound Transit is likely to award a $19.5 million contract to Condon Johnson to cut a path under Interstate 5 for the tunnels that will run between downtown Seattle and Capitol Hill. Condon Johnson’s bid was more than 30 percent under the engineer’s estimate. To make way for the tunnel boring machine, Sound Transit’s contractor will drill holes in the cylinder pile walls buried along the freeway and fill them with lean concrete that the boring machine can drill through.
These pile walls, which have giant steel beams in the middle of each cylinder, are about 50 feet deep and they keep Capitol Hill from sliding into downtown Seattle.
Gray said to anchor the walls “we’ll have steel tiebacks going from the walls more than 100 feet into the side of the hill.”
Going under a single-digit interstate through a major city while the interstate is operating will be a significant engineering feat. I hope it makes it onto Colossal Construction.
University Link will open in 2016.
Discovery Networks does like it when people suggest topics for shows.
Regardless … I cannot see why the TBMs will cause any notice to I5
They have to hold the freeway up as they tunnel under it. This isn’t a deep-bored tunnel, Westlake station is about fifty feet under the ground, and I-5 is in a retained cut, plus the express lanes are under that.
The Link tunnels will go right through the retaining walls. We don’t want Capitol Hill to slide into Downtown Seattle and I-5, don’t we?
I remember watching a Discovery show about the Big Dig; they had to freeze the soil to tunnel under busy railroad tracks. I don’t think we’re that extreme.
The U-link tunnels are passing not too far under the I-5 roadway, through the roadway support structure and retaining wall structure keeping Capitol Hill from sliding into the highway.
The tunnel consrtuction can’t cause any settling or structural damage to I-5 or the retaining walls.
You’ll notice it for a while. They have to close the Olive Way exit and the reversible express lane exit for a year.
It would be cool if they could somehow expose the lightrail under the freeway so when you look down from Pine St. you can see the various levels of freeway and under that–a lightrail! Probably not very practical though.
Seriously though, I hope we find money to put a lid over the entire segment between the convention center and Pine/Boren. I’ve read in several places that it was engineered for such a thing.
Do we have a kick-off groundbreaking date yet?
Does anyone know if they will open the Capitol Hill station well before they reach the University, or will we have to wait for the completion of the whole line before any part of it opens?
Tim
It is my understanding that 3 TBM’s will be used on U-Link, all starting at the Cap Hill station.
two TBM’s will head north to UW, the third will head to the Transit Tunnel. When the Transit Tunnel TBM arrives, it will be broken down, and brought back to Cap. hill to make a second run.
Now if we are really smart about timing, we can hope that the two UW bound TBM’s will be able to continue tuneling on to NorthGate, and that the UW station can be opened behind them, realistically this means thatthey would have to get to the Brooklyn station before the UW station could be opened for general usage, as the wxcevated material hasto come out of the tunnel somewhere, and in this model UW makes the most sence. Again we can hope ;)
Three? Everything I’ve read on the Sound Transit site suggests they’ll have just one, which I found rather surprising.
This is where I got the 3, although it appears that 2 start at tue UW going towards Cap hill, not the other way arround
http://watransportation.blogspot.com/2008/01/sound-transit-tunnel-edition-transit.html
Er, maybe they have two. the gnatt chart in this presentation suggests two (U220 & U230).
This article tells us that dirt will be removed from the University station, implying that at least one TBM will start there.
The husky stadium area will handle dirt from the UW-Capitol Hill tunnels. The CHS station will handle dirt from the Capitol Hill-Pine St stub tunnels.
I thought the UW objected to using the Husky Stadium site for tunnel spoils removal? Though which direction the tunneling goes doesn’t really matter from my POV.
I’d love to see the tunnel between Husky Stadium and 45th & Brooklyn dug at the same time as the tunnel to CHS. However I’m well aware that speeding up the Husky Stadium to Northgate segment is going to require a big pile of money from somewhere. Still I wouldn’t be supprised if North link to Northgate will be able to get around 40% federal funding.
how much ridership will be lost by having the station at husky stadium as opposed to the heart of the university district at 45th & brooklyn?
does the design of the route in the vicinity of husky stadium allow for a light rail branch east over 520 in the future?
According to the EIS UW station has 13,000 daily boardings at opening and Brooklyn has 8,500 daily boardings at opening. Presumably some of the Brooklyn station riders will use the UW station. I’m guessing the loss will be something on the order of 7,000 daily boardings.
Interesting that Central link from Westlake to S 200th is estimated to only have 39,500 2015 daily boardings. Even with adding only 2 stations U-link looks like it will more than double system ridership.
I should have read further in the North Link SEIS.
According to table 3.2-12:
2015 Daily Boardings
U-link:
UW Station 17,500
CH Station 11,000
N Link total 47,500
Brooklyn:
Brooklyn 9,500
UW Station 12,000
CH Station 12,000
N Link total 55,000
So 7,500 daily boardings by not going to Brooklyn & 45th.
Last I heard there will be 3 TBM’s working on U-Link: Two starting at the U and heading south, and one starting at the Cap Hill station and heading south. I would presume that one of the TBM’s that started at the U would continue south through the Cap Hill Station and eventually reach downtown. Doing it this way would avoid multiple assembly and disassembly steps (Only 1 assembly and disassembly step for each TBM).
But that is just a guess.
Time wise, teh above does not buy any improvements.
Given that UW to CapHill is twice as long as CapHill to DT running one TBM CapHill to DT, and reassembling it for a second run would buy an improvement in timing
I found it kind of weird that the Seattle Times article today marked everything at the UW station as “proposed,” like the “proposed pedestrian bridge” and the “proposed station,” considering there article is all about how we got the grant and construction is starting.