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Project Title & Location
I-5 Ship Canal Bridge Noise Study,
Seattle
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Project Description
WSDOT has been evaluating new and innovative noise-reducing elements to address freeway traffic noise in neighborhoods surrounding the I-5 Ship Canal Bridge. We have identified three potential options for reducing noise: 1) For reverberant and/or reflective noise: Noise-absorptive materials on the ceiling above the I-5 express lanes. 2) For direct noise: Street-level noise walls near the bridge approaches. 3) To reduce noise at the source: Replacement or rehabilitation of the pavement.
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Contractor/Consultant
EnviroIssues, Parsons Brinckerhoff, HDR
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Recent Progress
In April 2008, the team convened a group of acoustics experts to evaluate noise-reducing elements for freeway noise from the Ship Canal Bridge. Experts identified different types of noise coming from freeway traffic on the Ship Canal Bride, and assessed different options to address each type of noise. Based on the experts’ recommendations and to most effectively utilize the allocated funding, WSDOT plans to install a 1,000 foot long test section of a noise-absorptive ceiling treatment on the south concrete approach and monitor results. The design team is determining the exact configuration and location of the ceiling treatment test section, and plans to begin installation in late 2009.
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Design Construction Impacts
Construction is expected to begin in late 2009 and will involve the placement of a ceiling treatment test section on the I-5 Ship Canal Bridge. Details of the design will be finalized as plan preparation is completed.
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Environmental Impacts / Compliance
A Shoreline Permit Exemption was received on 12/19/2007 for the south approach staging area.
A Shoreline Permit Exemption is expected for the north approach staging area. The design office is waiting on the final documentation.
No other environmental permits are expected for the project.
Requests for noise variances for night time work are planned to be submitted to the City of Seattle later this year.
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Impacts to Traffic
Work related to Traffic Control Strategies will begin next quarter. The work could involve modifications to off-ramps and possible lane restriction on I-5 for night work. Details of these impacts will be finalized as plan preparation is completed.
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