Bertha still stopped in tunnel, but new overpass to open
A bridge for waterfront truckers opens Monday just south of the Alaskan Way Viaduct, while workers at the new tunnel start building road decks.
Seattle Times transportation reporter
Even though the Highway 99 tunnel machine hasn’t budged for seven weeks, roadwork at the surface keeps moving at a steady pace.
A new overpass opens at 5 a.m. Monday, connecting Sodo streets with Terminal 46 at the Port of Seattle. This crossing will help trucks bypass a freight-railroad track — averting the risk of a 20-minute delay.
“If freight can’t move, nobody moves,” said Matt Preedy, deputy director for the state’s Highway 99 program.
The $29 million crossing was completed by Atkinson Construction, the same firm that built a temporary span for Interstate 5 in June, after part of the Skagit River bridge collapsed. To apply the final touches, the southbound Alaskan Way Viaduct exit to South Atlantic Street will be closed all weekend.
Meanwhile, Seattle Tunnel Partners has started to build the tunnel’s double-decked south portal, where traffic eventually will enter the same pit where tunnel machine Bertha was launched July 30.
After mining 1,019 feet, the giant 57-foot-diameter drill has been halted since Dec. 6, when the rotary cutters stopped grabbing dirt. Officials say they don’t know when drilling will resume.
The new overpass includes sidewalks, and the waterfront bike trail to be rebuilt beneath the bridge next winter. The north leg of the overpass is a stub for now, but will connect to the new waterfront Alaskan Way, a year or two after the tunnel is done in 2016.
Until now, container trucks going east-west have been impeded by a dead-end track, where railcars are attached to other trains in the nearby Seattle International Gateway yard.
Workers inside the tunnel machine will continue to examine the cutter head of the tunnel machine this weekend. So far, a steel-pipe fragment and a 3½-foot wide chunk of concrete have been found in 84 hours of inspection. The state Department of Transportation says neither object is thought to be capable of stopping the machine.
Asked whether the drive motor or other mechanical parts sustained damage, Preedy said there is “none discovered at this time” during the ongoing review.
“Things are progressing according to plan. The investigation is making progress and Seattle Tunnel Partners will let us know when they want to mine,” Preedy said in a statement Friday.
The state has recruited a panel of outside experts to review tunnel-boring operations.
Mike Lindblom: 206-515-5631 or firstname.lastname@example.org