Project vicinity map.
Crews erected the first of sections of new noise walls on the southwest corner of the bridge the night of Jan. 13, 2009. After walls are installed at each corner of the bridge, a sound-absorbing material will be applied to the traffic-facing side of the walls.
Each time a vehicle passes over the expansion joints at either end of the new Tacoma Narrows Bridge, a loud zipper noise reverberates through nearby communities.
October 2009
Work is 75 percent complete
Current work includes applying sound-absorbing material to the walls and painting.
Traffic impacts this week
Crews close the HOV lane overnight Thursday, April 30 and Friday, May 1. Work hours are 10 p.m. to 5 a.m.
View a drawing of the noise walls.
Why is WSDOT
building noise barriers on the new eastbound Tacoma Narrows Bridge?
The eight-foot long steel expansion joints at the east and west ends of the new Tacoma Narrows bridge created an unforeseen noise impact.
Each time a vehicle crosses the expansion joints, a loud zipper-like noise is generated. Neighboring communities at both ends of the bridge complained about the zipper sound, prompting a noise study.
The noise study revealed that noise levels are at or near the standard acceptable level of 67 decibels. However, because of the unique sound, a determination was made that noise walls are warranted.
The End Result
Crews will construct four noise walls, two facing walls on each end of the bridge between the concrete approach and the expansion joints. The walls attach to the existing traffic barrier.
Each of the four walls are about 100 feet long and range in height from eight to 10 feet. The walls are designed to mimic the shape of the bridge anchors and are covered with a special concrete sound-absorbing material called SoundSorb™.
SoundSorb™ is a cement-based sound abatement product designed to absorb sound energy. Engineers expect the SoundSorb™ material to significantly reduce the expansion joint noise heard by nearby communities.
Project Benefits
- Noise - This project reduces the noise impact of the new bridge on neighboring communities.
- Innovation - This project is a test of the SoundSorb™ sound-absorbing material. If SoundSorb™ works as expected, it could be used on other WSDOT projects.
What is the project timeline?
The new noise walls are installed at each corner of the bridge. Work was suspended Feb. 23 for at least 30 days to wait for a warm-weather window to complete the next phase work, installing the sound-absorbing material on the walls. The project is 75 percent complete.
The construction contract was awarded to Tri-State Construction, Inc. of Bellevue in July 2008.
Financial Information
Total cost of this noise wall is about $1.2 million and is part of the $735 million price tag for the new Tacoma Narrows Bridge - which is on pace to finish about $114 million under budget.
WSDOT awarded the $531,698 construction contract to Tri-State Construction, Inc.
How can I get more information?
Contact:
Rumina Suafoa, Project Engineer
WSDOT Tacoma Project Engineer Office
1614 South Mildred, Suite M
Tacoma, WA 98465-1626
Phone: 253-534-3100
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