Drivers who use I-405 in Renton during the late and early morning hours should prepare for delays beginning Thursday night, Feb. 4.

Crews working for WSDOT will close lanes and coordinate with the Washington State Patrol to perform rolling slowdowns so crews can set girders for a new Benson Road S. bridge over I-405 in Renton. Work is expected to wrap up Friday, Feb. 12.

“We’re doing this work at night when traffic volumes are their lowest,” said WSDOT Project Engineer Lisa Hodgson.

Drivers should plan for delays and consider alternate routes like I-5 and I-90.

When complete, this project will improve access to downtown Renton, relieve traffic congestion on the I-405 interchanges at SR 167 and SR 169, and increase freeway capacity for both commuters and freight haulers.

During the work, a 650-ton hydraulic crane will hoist 20 concrete girder sections, one at a time, onto piers that will support the new bridge. Each girder section weighs as much as 190,000 pounds and ranges from 73 to 125 feet long. When connected, these sections will span more than 500 feet across I-405. Four of these spans will form a heavy-duty backbone for the bridge. This bridge is one of the longest on the I-405 corridor because it crosses the freeway at an angle and must accommodate new on- and off- ramps to and from Talbot Road.

The new bridge is part of the $83.6 million Renton Stage 2 project that adds a lane on I-405 in each direction between SR 167 and SR 169 and a half diamond interchange at Talbot Road. The project is funded by the 2003 and 2005 gas tax increases.