New WSDOT Research Report Featuring Reinhall Piles

Nov. 29, 2016

Underwater Noise Reduction of Marine Pile Driving Using a Double Pile: Vashon Ferry Terminal Test

Impact pile driving of steel piles in aquatic environments produces extremely high underwater sound levels. To address this problem, a double-walled pile has been developed to decrease the total noise transmitted into the water and substrate. The double-walled pile consists of two concentric steel pipe piles flexibly connected by a special driving shoe, allowing for an air gap between the two tubes. The double-walled pile is driven into the sediment by using traditional equipment that strikes the inner pile only. The air gap between the inner and outer pile and the flexible coupling prevent the radial deformation wave produced by the pile hammer from interacting with the water and the sediment. A second full-scale test of the double-walled pile technology was performed at Vashon Island, Puget Sound, Washington. A potential reduction of the peak pressure in excess of 17dB was observed for the double pile and of 16 dB for the mandrel pile. Root mean square (RMS) levels and cumulative sound exposure levels (SEL) decreased by 13 dB and 12 dB, respectively. Use of the WSDOT Geotechnical Design Manual Pile Driving Formula showed that the pile capacity of the novel piles was comparable to that of a control pile with the same outer diameter. PDA (Pile Driving Analyzer) data were also collected from both the inner and outer piles of the mandrel and double piles and will be used to modify current software for predicting drivability and stresses in the piles (WEAP (Wave Analysis of Pile Driving) analysis) and for estimating load capacity after driving (CAPWAP (Case Pile Wave Analysis Program) analysis).

"This new research shows we can minimize underwater pile driving noise to avoid harm to mammals and other protected marine species. The new sound attenuation method may also save project construction time and money."
Rhonda Brooks, Research Director, Washington State Department of Transportation

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.