We recently wrapped up a three-week test pile and noise reduction study in Lake Washington. This work was done to see how future bridge construction could be conducted more quietly to protect nearby homes, wildlife and fish from noise.
As part of this work, crews used a combination of vibratory and impact hammers to install – and later remove – nine steel test piles north of SR 520 between Portage Bay and the western high rise in Lake Washington.
Map of in-water drilling locations.
We learned that, in some cases, crews may be able to vibrate future SR 520 bridge piles into position, which could help reduce the noise from pile driving.
We also monitored the noise caused from pile driving and tested innovative techniques for blocking noise. The methods included a “bubble curtain,” where air pumped underwater prevents noise from traveling; a “noise shroud” made of sound-dampening fabric around the work area, and steel casings to block the sound of pile driving.
For photos of the work, check out our Flickr page.
Photos of previous fieldwork
Nov. 17, 2008 - Land drilling on the Eastside
Oct. 29, 2008 - The smaller barge operating in the Montlake cut area.
Oct. 15, 2008 - The Seahorse barge in Lake Washington photographed from an SR 520 bridge camera
Oct. 7, 2008 - The Seahorse barge used for drilling in Lake Washington. Its dimensions are 40 feet wide by 110 feet long.
