It seems that everything connected with the effort to dig a highway tunnel under downtown Seattle is big -- from the tunneling machine that stopped working last December, to a large plywood wall planned to shield neighbors from the noise of repairing the machine.
Washington Transportation Department spokeswoman Laura Newborn said Thursday that the noise-blocking wall will be as tall as the lower deck of the Alaskan Way Viaduct. The wall will soon rise out of the ground near the spot where crews will dig a 120-foot-deep pit where they will work on the machine known as Bertha.
Newborn says the tunnel contractor, Seattle Tunnel Partners, is still finalizing a repair strategy. Plans so far call for the tunneling machine now located about 60 feet below ground to dig forward into the pit, so crews can partially disassemble Bertha and repair the seal system and main bearing.
The machine stopped working in early December about 1,000 feet into the 1.7-mile Highway 99 tunnel that will replace the viaduct.