A bite out of the middle: Kiewit begins demolition of double-deck viaduct

Posted on Mar 11 2019 1:29 PM

Demolition of the Alaskan Way Viaduct hits a dramatic milestone this week as the contractor begins removing the first section of the double-deck structure. Until now, the large green and white machines have been munching and hammering on the viaduct’s edges and tucked-away sections. This week, they start chewing on the viaduct’s meaty middle.

The contractor Kiewit and their subcontractor Ferma have a multi-step schedule for taking down the viaduct that involves crews working at several locations at once. They began in mid-February at three locations: the Columbia Street on-ramp; the western half of the viaduct near Pike Street; and the very north end of the viaduct around the intersection of Western Avenue and Bell Street.

So far Kiewit has removed 450 feet of the Columbia ramp, about 360 feet of the viaduct near Pike street, and about 650 feet of bridge at the viaduct’s north end. In all, roughly 22 million pounds of concrete and steel has been hammered and munched off the structure. Kiewit trucks the rubble down to Terminal 25, where the rebar is removed and the concrete broken into small pieces for eventual use as fill in the Battery Street Tunnel. A small amount of the concrete is being used as rubble pads in work areas. The time-lapse video below captured the work at Columbia Street:

Over the weekend, the large muncher machine used at Pike Street was slowly moved down to Columbia Street. Crews will use that machine this week to begin demolishing the viaduct between Columbia Street and Yesler Way. First removing the top deck and then the lower deck, crews will work their way north along the waterfront. Ahead of demolition, Kiewit will fence off the work zone and prepare the area. Behind demolition, crews will clean up and restore the ground to its previous condition.

Diagram of viaduct showing three stages of work as demolition moves south to north along viaduct

Caption: Each work zone has three areas: prep, demolish, and restore.

Along the waterfront, the work zones will narrow Alaskan Way to one lane in each direction. Drivers should expect congestion in those areas, especially during peak commute times. People walking and biking in the area should expect detours around the work zone when trying to go east-west beneath the viaduct. Signs will indicate the closest open side street in either direction. The shared-use sidewalk on the west side of Alaskan Way will remain open, but the path on the east side of the street will be closed when it is part of the work zone.

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