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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
The project team is designing a ceiling treatment test section to be installed on the south concrete approach beginning in late 2009. In January, the team conducted noise monitoring near the south approach of the bridge. This information was used in an EASE noise model to help confirm the estimated reflected noise coming from the I-5 express lanes and the noise reduction benefits that may be achieved by installing the test section. The results of this model will help the team determine the configuration and limits of the ceiling panel test section.
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Design Construction Impacts
Construction is expected to begin in early 2010 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. It is anticipated that continuous two lane closures will be used to accommodate other ramp and highway closures and minimize impacts to the traveling public.
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