Viaduct to close this weekend for full inspection

The Alaskan Way Viaduct will be closed this weekend for its semiannual inspection.

Since the 2001 Nisqually earthquake, the state Department of Transportation has conducted a full inspection of the structure every six months to closely monitor any settling or other signs of deterioration. The DOT also conducts three-month visual inspections as a safety measure.

"We follow an aggressive inspection schedule for the Alaskan Way Viaduct. Going out there every three months to check existing cracks and settlement gives us another way to ensure the viaduct remains safe for drivers," says Craig Yasuda with the DOT's Bridge Preservation Office.

The week after the inspection, DOT crews will begin work to strengthen the columns between Columbia Street and Yesler Way, where the viaduct has settled approximately 5 inches since the earthquake. The DOT determined that the threshold for emergency repairs was 6 inches but has decided to make the repairs sooner because of a trend of continued settling.

The repairs, which will take about six months to complete, will prevent the columns from sinking further into the soil. This is the first of six safety and mobility projects designed to repair or replace more than half of the deteriorating viaduct.

In addition to inspecting the viaduct, state and city crews will remove loose concrete; repair potholes, expansion joints and bridge rails; apply a protective coating to exposed rebar; wash the walls of the Battery Street Tunnel; and test the levels of corrosion in the tunnel.

Crews will close both viaduct decks on Saturday from 6 a.m. to 7 p.m. from Spokane Street through the Battery Street Tunnel. Unlike previous inspections, the tunnel will remain closed Saturday night for corrosion testing.

On Sunday crews again will close both decks at 6 a.m. from Spokane Street through the Battery Street Tunnel. Because of an afternoon Seattle Seahawks game, the lanes will reopen early. The southbound lanes will open at 3 p.m., and the northbound lanes will open at 4 p.m.

The DOT will release inspection results on Oct. 19.

Meanwhile, today through Friday, Seattle Department of Transportation bridge crews will be repairing a guardrail on the viaduct that was damaged over the weekend. The far-left lane northbound will be closed near South Massachusetts Street.

Susan Gilmore: 206-464-2054 or sgilmore@seattletimes.com