Concentric Pile Design for Underwater Noise Reduction

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Solution Overview

Problem

Pile driving in water generates extremely high underwater sound levels, causing environmental disturbances and regulatory delays, as existing noise mitigation methods like bubble curtains and Temporary Noise Attenuation Piles (TNAP) are not effective in addressing sound transmission through sediment.

Innovation Solution

A pile design featuring a concentric inner and outer tube configuration, where the outer tube is not directly impacted by the pile driver, and a compliant annular material is used between the tubes to isolate the water from the radial expansion wave, allowing the outer tube to be pulled into the sediment without direct impact, thereby reducing sound propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional pile driving methods are used, then construction productivity is maintained, but underwater noise levels become excessively high causing environmental harm

Engineering Contradiction:

Improveunderwater noiseVSAvoidconstruction productivity

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The pile is segmented into an inner member and an outer tube, allowing the impact force to be applied only to the inner member while the outer tube remains isolated from direct impact, thereby reducing noise transmission to the surrounding water environment

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The inner member is nested within the outer tube, creating a concentric configuration where the inner member absorbs the impact energy while the outer tube provides structural support and shields the water from the radial expansion wave generated during pile driving

Inventive Principle:

Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If sound abatement structures like bubble curtains are installed, then some noise reduction is achieved, but sound transmission through sediment remains high

Engineering Contradiction:

Improveunderwater noiseVSAvoidnoise mitigation effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The harmful impact action is extracted from the outer tube by applying force only to the inner member, preventing the generation of strong radial expansion waves that would otherwise be transmitted through the sediment and water, thereby addressing the limitation of prior art methods that did not eliminate this transmission path

Inventive Principle:

Principle #2Taking out (Extraction)

3Force

If the outer tube is directly impacted during pile driving, then driving force is efficiently transmitted, but radial expansion waves are generated that propagate sound through water

Engineering Contradiction:

Improvedriving force transmissionVSAvoidradial expansion wave

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The inner member acts as an intermediary that receives the impact force from the pile driver and transmits it to the pile group through the driving shoe, while the compliant annular material further mediates between the inner member and outer tube to prevent direct transmission of the radial expansion wave to the outer tube and surrounding water

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design significantly reduces underwater noise by shielding the radial expansion wave from the water, effectively mitigating sound transmission and meeting noise reduction criteria not achieved by prior art methods.

Implementation Method 1

a compliant annular material is used between the tubes to isolate the water from the radial expansion wave

Methodology Applied

Scientific EffectSound absorption: Acoustic Absorption

Data Source

PatentUS8622658B2Pile to minimize noise transmission and method of pile driving

Publication Date: 2014.01.07 UNIVERSITY OF WASHINGTON THROUGH ITS CENTER FOR COMMERCIALIZATION

AI summary

A pile and method for driving a pile includes a pile having a structural outer tube, and an inner member disposed generally concentrically with the outer tube. The outer tube and inner member are fixed to a driving shoe. The pile is constructed and driven such that the pile driver impacts only the inner member. The impact loads are transmitted to the driving shoe to drive the pile into the sediment, such that the outer tube is thereby pulled into the sediment. In a particular embodiment the outer tube is formed of steel, and the inner member also comprises a steel tube. In an alternative embodiment one or both of the inner member and the outer tube are formed of an alternative material, for example, concrete. In an embodiment, the outer tube has a recess that captures a flange on the inner member. In an embodiment the outer tube is attached to the inner member with an elastic spring.