Dynamic Response of a Sheet Pile of Fiber-Reinforced Polymer for Waterfront Barriers

Abstract

This paper presents the results from a combined experimental and advanced computational study to understand the dynamic response of a pultruded fiber-reinforced polymer (FRP) sheet pile of 9 m length that is installed into the ground near Venice, Italy. The peak embedment force of 10 kN is applied at the top as a sinusoidal compression force having a maximum frequency of circa 760 Hz. Physical measurements from accelerometers are reported for the lateral deformation response of a single sheet pile and of a unit restrained by an installed waterfront barrier. A finite-element modeling methodology for the two test configurations is developed by using the Strand7 code, so that advanced computational results can be compared against the field application measurements. Closed-form equations for the fundamental frequency are developed, with one accounting for the presence of rotary inertia and shear deformation. Dynamic responses at different embedment lengths (1–7 m) are examined, and a very good correlation is found between theory and practice. Numerically, the performance of the FRP sheet pile is compared with the response of a fictitious sheet pile of steel and with two new FRP geometries that increase stiffness to minimize flexure about the minor axis of bending. By increasing the mass by 10%, the maximum lateral displacement can be the same as the steel unit and 1/20 of the tested FRP unit. Findings of the research demonstrate that the FRP unit can be installed by using the same pile driving rig and procedure for steel sheet piling.