Pile group effect on the wave loading of a slender pile: A small-scale model study

Abstract

Closely-spaced piles are the most essential components for the structural safety of some types of coastal and offshore structures. Wave-induced loading of such piles is among the most uncertain issues in the design of pile group-supported marine structures. Therefore, the correct estimation of the wave loading of a pile within a pile-group in different arrangements is crucial for both safety and costs. Unlike the case of single isolated piles, less attention have been paid to pile groups where wave–pile group interaction is more obvious due to interference effects that affect the wave-induced flow around the piles.In this study, the pile group effect on the wave loading of a slender pile due to non-breaking and focused breaking waves is investigated by means of small scale experiments performed in the 2m-wide wave flume of Leichtweiss-Institute for Hydraulic Engineering and Water Resources (LWI) in Braunschweig, Germany. Different pile arrangements including single, side by side, tandem, 2×2 and staggered with relative spacing of SG/D=0.5–5 were tested. Based on the results of this study an improved understanding of the processes associated with the interaction of waves and pile groups has been achieved.