Tukwila’s aging 42nd Ave South Bridge was the victim of an over height impact from a truck on Wednesday, Dec. 15, 2021, and was closed shortly afterwards by Tukwila Police.

The damaged bridge will remain closed until repairs are completed, to ensure the safety of all who use the route. The city said that repairs are weather dependent and may take 4-6 weeks.

The bridge is considered critical infrastructure that provides access to Tukwila’s Allentown neighborhood, the BNSF intermodal yard, Baker Commodities and serves as an east/west connection across the Duwamish River for the region, hosting 3,000 trucks and 7,000 passenger vehicles per day.

Estimated cost to repair the bridge is $221,000.

The city has plans to construct a new bridge at this location by 2025, and has already secured $13.5 million towards that – approximately half the cost.

Here’s more info from the city:

On Thursday, Dec. 16, a King County inspection crew performed an in-depth inspection of the damaged areas. Officials determined that the truck struck one sway frame of the bridge and inflicted some critical damages to it, as well as its associated vertical elements of the through-trusses of the bridge.

Fortunately, it appears that no member of the truss bridge has been separated or sheared off, and damages are limited to the one mentioned sway frame area. This observation was made by TranTech Engineering, LLC, a structural engineering firm that had conducted past structural analysis and is very familiar with this bridge.

On Friday, Dec. 17, the City and TranTech team met a heat straightening contractor, Flame On Inc., at the site and it was determined that this repair is feasible and effective for the observed damages. TranTech recommends that the City obtain the services of this contractor for repair of the described sway frame damages. The King County bridge inspectors are also in agreement with this recommendation.

City staff are moving forward with procuring the contracts necessary to perform the repairs immediately. The Mayor has declared a state of emergency that allows work to move forward quickly. These repairs are weather dependent and may take 4-6 weeks. Additional inspections and structural analysis will determine the future next steps.The bridge closure continues until further notice and City staff will continue to monitor the detour routes.

“Thank you for your patience and understanding during this construction period,” the city said.

More info on the city’s Allentown Truck Reroute here.