The state is on schedule to complete the second part of major improvements to Interstate 405 through downtown Renton six to nine months early, said the state transportation department project engineer.
The earlier completion date – the original date was September 2011 – is possible because the effort to move 10s of thousands of yards of soil for the project went so smoothy, said Lisa Hodgson, who oversees the project.
“The earthwork went much faster than we had anticipated and helped us get a jump start on the project,” Hodgson said.
The project includes the addition of lanes, a new Benson Road bridge and an interchange serving Talbot Road.
Now, the most visible part of the project is building piers for the new Benson Road bridge over the freeway. Next week, the state will place four girders on the piers that will support the bridge deck. That work will cause some slowdowns on the freeway and the closure of Benson Road in the area.
Each girder comes in five pieces which are bolted in place. When the work is done, two temporary piers will be removed and two permanent ones will remain.
The girders are up to 132 feet in length and are the longest ones ever placed in the state.
The state is moving the Benson bridge to make room for the offramp from southbound 405 to Talbot Road.
Then, next July or August the state will demolish the old Benson Bridge over two weekends, which will disrupt traffic, mostly at night.
The state is encouraging drivers to find alternate routes while the girders are being placed.
Here’s the latest closure information:
- Feb. 4, (Thursday p.m. – Friday a.m.) 6 p.m. – 4 a.m., Benson Road closure
- Feb. 5, midnight – 4 a.m., I-405 northbound rolling slow-down and northbound SR 167 to northbound I-405 ramp closure
- Feb. 6, 3 a.m. – 6 a.m. I-405 southbound rolling slow-down
Schedules could change so check for updates at http://www.wsdot.wa.gov/projects/i405/sr515interchange.
