Fine Tuning Continues on SR520 Project Noisy expansion joints
On April 12, LCC met with WSDOT officials and neighbors from Medina to hear a proposed solution to reduce noise on the large expansion joints on the new SR520 floating bridge.
The project engineers worked with Mageba, the manufacturer of the expansion joints, and recommended a pilot program to replace the joint seals with a new design and fill them with one or three durable foam materials to absorb the sound. The solution is similar to the Vancouver Bridge, but the durability of the foam and continual maintenance are negatives. Washington State allows studded tires and chains, which may also deteriorate the foam installation.
The cost of the installation is estimated at $2 to 6 million after an initial pilot program to determine if it will work. The three-way movement of the floating bridge precludes using the “sinus plate” system that muffles expansion joints, which will be installed on the WABN section of the bridge in Union Bay. Lighting fixtures.
A group of Laurelhurst neighbors have been working with WSDOT to test types of shields to re-direct the glare lighting on the north side of the SR520 floating bridge downward and away from the spill onto Lake WA and nearby residences. WSDOT has worked with the lighting fixture manufacturer to produce various prototypes that can be retrofitted onto the existing fixtures.
Two new improvements are being tested with feedback given to WSDOT. The fixtures include enclosing the sides of the louvered shield to capture spilled side light. The second one allows light to shine from the bottom of the fixture.
A May public meeting is planned to determine the best solutions, and participating neighbors are encouraged by the progress and teamwork from WSDOT.
Noise variance request by WSDOT from the City of Seattle for night noise construction for seven years More than 230 public comment letters were submitted to the City in opposition of allowing a seven-year noise variance up to 80 decibels (twice the EPA standard) by WSDOT while they demo and construct the “Rest of the West.”
LCC opposed it as well and asked that only EPA-level decibels be allowed for short terms for targeted work throughout the project. On April 27, Seattle DCI DENIED the request and will require WSDOT to re-submit for any/each noise variance. A big win!
LCC Asks City to Deny Noise Variance
LCC wrote a letter to the City of Seattle to recommend strongly that the requested SDOT increases in nighttime decibel limits on SR520 construction be denied.
LCC maintains that these noise level increases are not justified considering the amount of disturbance to area residents. SDOT filed an application for a Major Public Project Construction Noise Variance (MPPCNV) for at least the next seven years for the build out of the “Rest of the West” – the connection of the new SR520 bridge to I-5 – which includes demolition and construction in Lake Washington, Union Bay, in and across the Montlake Cut and though Portage Bay.
(photo courtesy of WSDOT)
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