Viaduct has not settled additionally

Inspection results show no additional settlement of the Alaskan Way Viaduct between Columbia Street and Yesler Way.

However, due to half an inch of settlement at two piers found during previous inspections over the last year, the Washington State Department of Transportation will move forward with repairs in this area.

"We are pleased with the results of this inspection, but the situation is still urgent," said Jugesh Kapur, state bridge engineer. "We are moving ahead to make repairs in the area between Columbia Street and Yesler Way to strengthen several footings as soon as possible."

The inspection of the 54-year-old State Route 99 viaduct showed that in this one block area the total amount of settlement since the 2001 Nisqually earthquake remains at four and three-quarters inches. No structural damage was found during the inspection.

The repair work, estimated to cost $5 million, is one part of several improvements recently announced to replace or repair over half of the viaduct. Work will begin in the fall. Repairs involve drilling a series of vertical micropiles, which are steel tubes filled with concrete including a steel rod in the middle. These micropiles will reach through the unstable fill and into the stable glacial till soil, making a wider and stronger column foundation and preventing further foundation settlement.

The work is expected to take five to six months to complete. It will not require lane closures, but some parking restrictions underneath the viaduct may be needed.