Acoustic transmission loss in industrial pile driving

Jan. 31, 2015

AUTHORS

Mark L. Stockham, Peter H. Dahl and Per G. Reinhall

ABSTRACT

Industrial pile driving is a source of high‐level underwater noise and new understanding of its effects on the behavior and health of marine mammals and fish has motivated numerous regulations intended to limit these effects. Of primary importance is to identify a suitable transmission loss model to predict where, given a certain source level, the noise produced by the pile driving reaches regulatory thresholds. In November 2009, data were collected from a marine construction site in the Puget Sound. Measurements at two ranges (8 and 12 m) from the pile being driven were taken using a nine hydrophone vertical line array (VLA). Concurrently, at a range of approximately 120 m, there was also a single hydrophone at a depth of 5 m (sensitive to frequencies greater than 10 kHz). By comparing the levels at the VLA to the more distant hydrophone across a number of pile strikes (each forming a identifiable short‐ and far‐range pair), the transmission loss can be estimated. These results are in turn modeled using an approach based on the parabolic wave equation. [Work was funded by the Washington Department of Transportation.]

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http://scitation.aip.org/content/asa/journal/jasa/129/4/10.1121/1.3588094

"By reducing underwater noise from pile driving by 20 dB, implementation of MCT’s technology could potentially reduce the Zone of Influence and required marine mammal monitoring, expedite consultation processes with the Services, and minimize construction delays due to the proximity of marine mammals."
Cameron Fisher, Biological Lead, 48 North Solutions, Inc.

Hear the difference

Recorded from hydrophone deployed at 10m during subscale testing of 8" steel piles in Seattle, Washington in 2013.

You are hearing 4 strikes of a standard pile followed by 4 strikes of a Reinhall Pile™. Notice the difference.