Wednesday, July 29, 2020

Building a bridge over I-5 in one weekend, and how you can help

By Laura Newborn

The most dramatic sign of progress on our SR 167 Completion Project is a new bridge in Fife that's about to take shape in just one weekend.

On August 28 and 29, our contractor, Guy F. Atkinson Construction, will close both directions of I-5 between Federal Way and Fife to move 10 gigantic girders into place for the new 70th Avenue East Bridge. It's a heavy lift. Each girder is 220 feet long - almost the size of a 747-8's wingspan. Each one is 9 feet tall, 4 feet wide and 231,000 pounds. Installing these girders takes plenty of coordination, choreography and skill.
This bridge girder shows just how big these record-breaking girders are. The one belongs to the future southbound I-5 Puyallup River Bridge and is 223-feet-long. The Fife girders are 220-feet long. Combined, these two projects set the record for the largest pre-stressed concrete girders made in the US. They are made in Tacoma by Concrete Technology Corp.

Closing I-5 between Federal Way and Fife
Safely lifting loads this large across the highway requires a full closure of I-5 for two consecutive overnight periods. Each night, five girders will make the 5-mile, 45-minute journey from Tacoma's Concrete Technology Corp. to the bridge site in Fife. Cranes stationed on the southbound and northbound roadways will then guide each girder to its predetermined spot. Five girders one night and five the second night.

We chose weekend overnights for the work as they are the least-traveled times on I-5, but we understand there's never a good time to close a major interstate. Backups could be significant in both directions. And that's where we need your help. If possible, please avoid the area and skip discretionary trips during these hours:

Friday, August 28 and Saturday August 29
  • I-5 lane closures begin at 8 p.m. on Friday
  • All lanes of I-5 will close at 11p.m. between 54th Avenue East in Fife and SR 18 in Federal Way
  • Lanes start to reopen by 8 a.m. Saturday
  • All lanes will reopen by noon Saturday
Saturday August 29 and Sunday August 30
  • I-5 lane closures begin at 8 p.m. Saturday
  • All lanes of I-5 will close at 11 p.m. between 54th Avenue East in Fife and SR 18 in Federal Way
  • Lanes start to reopen by 8 a.m. Sunday
  • All lanes will reopen by noon Sunday
We need help from drivers
Drivers who must travel between Seattle and Olympia during the closure hours are advised to use SR 18, SR 167, and SR 512, which can accommodate the most traffic. The SR 99 detour provides access back to I-5. Southbound I-5 travelers headed to downtown Tacoma, Gig Harbor or points beyond will want to consider the SR 99 detour.


Benefits of building a bridge this way
One of the reasons we chose to build a bridge with these exceptionally long girders was to avoid long-term traffic impacts. Shorter girders would have required us to widen I-5 and build columns in the median – work that would have brought prolonged lane closures. The longer girders need one weekend to install. You can watch bridge construction and the girder lift on our real-time construction cameras.

In the end, this project will be worth it. When it opens in mid-2021, the new 70th Avenue East Bridge will greatly improve travel in the area by reducing congestion, improving freight mobility, and providing new options for people who walk and bike.