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.
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.