New cracks discovered on Seattle’s viaduct, another closure scheduled

As crews race to build its replacement before the next major earthquake, engineers have discovered new cracks on the Alaskan Way Viaduct.

The Washington State Department of Transportation reported on Monday engineers found the 1/16th of an inch fissures on the elevated roadway during an inspection on March 1.

Crews also discovered evidence of movement and widening of existing cracks along girders and supports near Spring and Seneca streets.

“We have some cracks that were existing that have widened and we have some cracks that have lengthened,” said State Bridge Engineer Tom Baker.

WSDOT said the viaduct is safe for drivers, but engineers will close the roadway down again on March 22 for a second inspection to gather more information before they can make repairs.

“I think these are the most significant in a localized area, which is why the need to take a closer look and to put some longer term instrumentation on them,” Baker added.

Engineers will install monitoring devices on the columns to track the movement and growth of the cracks over time. That information will help them identify additional repairs. Crews will also perform tests to determine how these newly discovered cracks respond to heavy loads and possibly fill them with epoxy.

Further closures are possible.

The WSDOT said the section where the cracks were discovered is more than a half-mile north of Bertha, the tunneling machine.

“While the cause of these cracks is still to be determined, it is not related to tunneling activity,” said the WSDOT.

The viaduct is inspected four times per year.