SuperPile 2017 Online Proceedings, (DFI)
Noise Attenuation Effectiveness and Potential Safety Benefits of New Double Walled-Pile Technology
Per Reinhall, Ph.D. and Julie Hampden, MMA
Impact pile driving of steel piles is a common construction practice in freshwater and marine environments for the building of structures and foundations. This practice produces high underwater sound levels that have proven injurious to aquatic fish and wildlife. To limit impacts to sensitive species, often resource management agencies limit in-water construciton windows to those months when the species are least likely to be present in the project vicinity. In some regions of the country, this forces contractors to construct projects during winter months when inclement weather and more challenging or dangerous work conditions are present. In addition, biological monitoring and noise attenuation techiques, such as bubble cutains and cofferdams, may also be required - resulting in additional complexities and risks for project delivery. Marine Construction Technologies in collaboration with University of Washington, and Washington State Department of Trasnportation has developed a pile that consistenly decreases the total noise transmitted into the water and that is relatively quiet in comparison to existing noise attanuation techniques. This technology could improve safety for contractors during project implementation by potentially expanding allowable work windows (due to the reduced risk to sensitive species) and reducing the complexity of project delivery by eliminating the need for monitoring and deployment of additional noise attenuation devices. Results from finite element modeling of the pile, scaled prototype testing, and full scale field testing in Commencement Bay (October 2014) and Vashon Island (October 2015) in Puget Sound, Washingotn indicate a reduction in the peak sound pressure between 14 and 20 dB relative to single walled piles at a range of approximately 10 meters.
|article #2681; publication #1031 (SP-2017)|