Thursday, November 16, 2023

I-405 overpass replacement in Renton gaining momentum

By Tom Pearce

We took a big bite out of the project to replace the Lind Avenue overpass above southbound I-405 in Renton a couple of weeks ago, and now we're getting ready for the next part of the job.

The big bite – actually many, many bites, were made by demolition equipment that tore down the north span of the overpass. This happened over the weekend of Nov. 4-5, when all lanes of the southbound freeway were closed.

It took about eight hours to rip down the damaged north span of the I-405 Lind Avenue overpass in Renton.

Now we turn our attention to installing the new girders. This work will happen during overnight closures of the southbound lanes, starting at 11 p.m. Monday, Dec. 4, through Friday morning, Dec. 7. The highway will reopen at 4:30 each morning.

The first part of the work, which included restriping both directions of 405 to accommodate construction as well as demolition, went well despite one hiccup. Our first night of striping was rained out. But our contractor, Johansen Construction, squeezed in the striping work during the weekend, thus avoiding more weeknight closures.

During overnight closures on southbound I-405, people traveling will need to use the SR 167 interchange to continue toward Tukwila and SeaTac International Airport.

The next big process is installing the eight new concrete girders that will support the north span of the Lind Avenue overpass. We can't have traffic on the freeway while we're putting up girders, so we'll have about a week of overnight full closures. People traveling will detour via the SR 167 interchange, Rainier Avenue and Grady Way before rejoining southbound I-405 at Interurban Avenue.

Once the girders are in place, we'll begin rebuilding the overpass deck. Some lanes of southbound I-5 will be closed overnight for this work, but we won't have to close all the lanes, so people won't need to detour.

We expect work to finish in spring 2024 and restore a vital connection over I-405 for people in Renton and others who use this freeway.

Girders were damaged by a backhoe

This all started back in June 2022 when a backhoe being towed on a trailer hit five of the eight girders supporting the Lind overpass. It basically damaged every other girder, so it was more cost-effective to replace the overpass than remove some girders without damaging others.

The backhoe damaged the first, third, fifth, sixth and eighth girders of the southbound I-405 overpass.

We are still working with the owner of the backhoe and their insurance to recover the costs to replace the overpass span.

A lot goes into replacing an overpass – design, hiring a contractor, getting materials, scheduling, etc. We appreciate the patience of the people who have had to use detours to get around this site, as well as the city of Renton, which has been a very helpful partner since this all starting in 2022.

It's taken a long time to get to this point, but we'll keep chewing away at this project into spring 2024 when we open the new overpass.