S 277th Bridge No. 3126 Replacement Project
Construction is underway. Single lane closures expected through November 2021.
Monday, July 26, 2021
Project construction will last through November 2021.
Expect traffic slowdowns: S 277th Street between West Valley Highway and 55th Avenue S will be reduced to one lane in each direction around-the-clock until the project is complete. View the project flyer PDF 1MB
This project replaces the 70-year-old S 277th Street Bridge No. 3126 over Mullen Slough with a four-sided concrete box culvert. The 16-foot-long bridge is located on a four-lane principal arterial road that connects Interstate 5 to State Route 167 in Kent and Federal Way.
Why King County is replacing this bridge
This existing S 277th Street Bridge is load-restricted and unable to support certain types of large trucks including some types of fire engines used by adjacent fire districts, full-size garbage trucks, dump trucks, and concrete mixers. The replacement culvert will provide unrestricted access for all vehicles. It will also provide environmental enhancements by improving fish passage and removing creosote timber pilings from Mullen Slough.
S 277th Street at this location has a traffic volume of about 23,000 vehicles per day, of which 2,600 vehicles are trucks carrying an estimated 4 to 10 million tons of freight per year. This road is a designated county snow/ice route, lifeline route, and Green River Valley flood evacuation route.
Construction will begin in summer 2021 and is expected to last approximately four months.
- Utility relocation: June 2021
- Equipment on site: July 2021
- Construction begins: July 2021
- Construction complete (anticipated): November 2021
Getting through the construction zone
Due to high average daily traffic on S 277th, and unfavorable detour routes, the existing bridge will remain open with travel lane reductions through the construction zone.
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Broch Bender, Communications Manager
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Esta pagina web - 28 de mayo de 2020 PDF 1MB
Determinación de no Impacto Adverso Significativo al Medio Ambiente (DNS por sus siglas en Inglés) - Fecha de emisión, 28 de mayo de 2020 PDF 198KB
Frequently asked questions
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Either the north half or south half of the existing bridge will be demolished and replaced during Stage 1 construction while the traffic is shifted to the other half of the bridge.
Stage 2 of construction would move traffic to the newly constructed half of the new structure, demolish the remaining half of the existing bridge, and finish constructing the remaining half of the new structure.
S. 277th Street both directions (eastbound and westbound)
King County will place warning/advisory signs informing drivers of reduced lanes and reduced speed limit ahead.
King County will place signs notifying drivers of upcoming and current project construction and construction impacts.
Check King County's My Commute Map
All lane reductions will be listed in advance on the King County My Commute map.