42nd Ave Bridge S Replacement Project

The type, size, and location (TS&L) report (please see the link below), 30% plans and estimate (P&E), 60% P&E, and 90% P&E have been submitted to the City to have city staff review and comment on the plans. At the 30% P&E submittal milestone, TranTech Engineering, LLC permit subconsultant began verifying what agencies require permit applications. Many of the permitting agencies would not field/take applications for permits until the 30% P&E threshold is met. At the 60% P&E review threshold, permit agencies informed project staff that internal permit processes require additional time for review and acceptance, partially due to staff shortages and environmental constraints. Given that the project staff understands the timelines and extent of the permit application, the design timeline has been adjusted to have advertisement-ready documents in August 2026.

The project team is currently coordinating with the Department of Natural Resources, US Army Corps of Engineers, US Coast Guard, Federal Highway Administration, Washington State Department of Transportation, Washington Department of Ecology, Washington State Department of Fish and Wildlife, King County Parks and Recreation, King County Sewer, Seattle City Light, local businesses, and Tukwila’s Department of Community Development. The project staff will also coordinate with multiple utility providers to relocate the current infrastructure.

PROJECT OVERVIEW

The 42nd Ave S Bridge is an important arterial for the City of Tukwila and surrounding communities. The bridge, designed in 1927 and built in 1949, is reaching the end of its design lifespan and needs to be replaced. The current 42nd Ave S Bridge consists of a 3-span 280-foot-long bridge with a new sufficiency rating of 6.00 out of 100 due the bridge strike and is considered both structurally deficient and functionally obsolete by the Federal Highway Authority (FHWA). The 2018 average daily traffic volume (ADT) was 10,300 vehicles per day.

A consultant team has been brought onboard by the City to develop a design for a replacement bridge. A component of the design work will involve gathering feedback from community stakeholders to guide portions of the design process. There will be multiple opportunities for the public to share their thoughts on bridge design and other project features.

In 2021 the bridge was struck by an over height truck resulting in damage to key structural members of the bridge. A heat straightening contractor was onsite to repair the compromised steel elements. Given the age of the steel and the damage from the bridge strike, the bridge was reduced to a one lane bridge to reduce the amount of vehicles that could cross the bridge.

The currently allows traffic to travel southbound to guide users toward a intersection with traffic signals.

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TIMELINE

The project is currently in the design phase which will continue through 2024.

FREQUENTLY ASKED QUESTIONS

What is the status of the 42^nd Ave S Bridge?

The 42^nd Ave S Bridge has been monitored in accordance with federal requirements, and since 2015, has been the subject of concern and evaluation by Tukwila Public Works, King County, and the Washington State Department of Transportation. Currently, the 42^nd Ave S. Bridge carries a sufficiency rating (SR) of 6.00 on a scale of 100 – this means that the bridge is in poor condition and in need of replacement. Specific technical examples of the bridge’s deterioration include compromised area due to truck strike, loss of shoreline protection, concrete cracking at the north pier, frozen bridge bearings, corrosion, pack rust, and impact damage on a fracture critical bridge. The primary responsibility of city government is to uphold and protect public safety, including the maintenance of infrastructure. In Tukwila, we are committed to a safe, transparent, and orderly replacement of this bridge.

Where are we in the process of replacing the 42^nd Ave S Bridge?

The City just returned the 60% plans and estimate comments back to the design engineers. The design team will incorporate the new questions/comments and move toward the 90% plans and estimate milestone.

Do you have an emergency plan in place in case the 42^nd Ave S Bridge collapses? 

The City closed the 42^nd Ave S Bridge in December 2021 due to an over height bridge strike. General vehicle traffic was then detoured to S 115^th St and trucks were detoured to the S 129^th St Bridge.

An analysis of the one-way traffic was performed six (6) months after the bridge was open. It was recommended that the 42nd Avenue S bridge continue to operate in the southbound direction. It is safer and more efficient for vehicles to exit the neighborhood using the traffic signal at the 42nd Avenue S/Interurban Avenue S intersection compared to exiting the neighborhood at the unsignalized S 115th Street/East Marginal Way S intersection.

Emergency response in any jurisdiction takes several factors into account, including the cause of any major incident. Whether failure of any structure is caused by fire or flood or natural disaster, responders first on the scene of any emergency situation are trained professionals who help to alert and call into service the appropriate agencies, and identify expertise and equipment needed to be most effective in securing and protecting public safety. As a best practice in emergency management, any emergency response of this scale would be managed and coordinated in accordance with the direction of the Tukwila Emergency Manager, King County, and the State of Washington.

How are you going to mitigate impacts during construction of the bridge, both to traffic in the Allentown neighborhood and to amenities such as the Community Center and spray park?

City has hired a design consultant to design the 42^nd Ave Bridge replacement. As part of this design, the consultant will evaluate traffic rerouting during the construction phase of the project.  If the reroute impacts the Tukwila Community Center, alternative temporary improvements can be made available during the time of construction to mitigate the impacts. More information on potential reroutes will be developed as the bridge design progresses and will be shared with the community. Furthermore, any construction impacts to the Tukwila Community Center will be rehabilitated to equal or better pre-construction conditions.

A temporary bridge is planned to be constructed just to the east of the 42^nd Ave S Bridge during the demolition and construction of the new bridge. The temporary bridge will again bring two-way traffic in and out of Allentown.

Why isn’t the City of Tukwila conducting an EIS for the 42^nd Ave S Bridge?

The new bridge at 42^nd Ave S will replace existing infrastructure and is not expected to have significant impacts requiring preparation of an EIS. However, environmental analysis is being conducted following applicable State Environmental Policy Act (SEPA) and National Environmental Policy Act (NEPA) procedures.

The City of Tukwila is committed to working with stakeholders as part of that process, including Allentown residents, local Tribes, Washington Department of Fish and Wildlife (WDFW), United States Fish and Wildlife Service (USFWS), United States Army Corps of Engineers (USACE), City of Tukwila Department of Community Development, Washington State Department of Transportation (WSDOT), US Coast Guard, Department of Ecology (DOE), Department of Archaeology and  Historic Preservation (DAHP), Department of Natural Resources (DNR), National Oceanic and Atmospheric Administration (NOAA) National Marine Fisheries Service.

The City is currently conducting an EIS study for the Allentown Truck Reroute project. Please refer to the following link for information on that project.

What can you do about trucks speeding on the 42^nd Ave S Bridge and through the Allentown neighborhood? And relatedly, can you do more to enforce weight/speed restrictions on the bridge?

The roads near and through Allentown, as well as heavily trafficked roads in many neighborhoods in Tukwila, are monitored to determine traffic patterns and usage. The City has performed a traffic study for the Allentown neighborhood and other neighborhoods in the City. The assessment includes collecting traffic data that will help us to identify issues with factors such as speed and solutions that could include safety measures like lighting, sidewalks, crosswalks, curbs, speed limits and enforcement, to help protect residents and drivers.

What other kinds of fundraising has the City undertaken to get funds for this project and a replacement bridge?

Since 2017, the City has been actively applying for grant funding for the 42nd Ave S Bridge Replacement Project. These grants are highly competitive, and the City was unsuccessful in receiving grant funds for this project until 2021.

The City has received grant funding from- $1.5 million from the Puget Sound Regional Council to complete the 100% design phase and move the project into construction by 2024, and $12 million from the Washington State Department of Transportation’s Local Bridge Program, which can be allocated for all project phases. Additionally, the Washington State Legislature passed the $17 billion Move Ahead WA transportation package, which included $17 million for the replacement of the 42nd Avenue Bridge.

PROJECT LIBRARY

• Duwamish Tribe comments on 42nd Ave S Bridge Replacement – 4/11/24
• 42nd Ave S Bridge Replacement Project – Final TSL Study Report (April 2022)
• February 22, 2022 Allentown Community Meeting Agenda & EIS Overview
• 42nd Ave S Bridge Replacement TSL Presentation (Presented at 2/14/22 Council meeting and 2/22/22 Allentown Community Meeting)
• February 14, 2022 City Council Packet – 42nd Avenue Type Size and Location Presentation and Study (includes full TS&L report and presentation used at 2/14/22 Council meeting and 2/22/22 Allentown Community Meeting)
• Project Fact Sheet (March 2021)
• March 30 Allentown Advocates meeting presentation (March 2021)
• March 30 Allentown Advocates recorded meeting (March 2021)
• Community Outreach Survey Results – Project Design Elements (October 2021)

CONTACT INFORMATION

For general project questions, please contact Adam Cox at 206-431-2446 or email Adam.Cox@TukwilaWA.gov.