Experimental and numerical investigations of a novel steel-UHPC-polyurethane composite fender against vessel collisions

Abstract

The protective devices for bridge piers are significant in reducing the impact force and damages on both bridge piers and vessels. In this study, a novel steel-UHPC-polyurethane composite fender with two-layer core structures is proposed. Two tested specimens with different core structures, namely the corrugated plate-tubes frame (CF) type, and the corrugated plate-horizontal tube (CH) type, were subjected to drop-hammer impact tests. The test results indicate that the impact force and damage mode of composite fenders are sensitive to the structural stiffness of the core structures. The relative stiffness between two layers of core structures affects their ability to deform cooperatively for energy dissipation. A finite element (FE) modeling method was developed and validated for the composite fender based on test results. The effectiveness of the composite fender used in a continuous girder bridge was demonstrated, by using the validated numerical methods. Subsequently, parametric analysis was performed, revealing that the thickness of core structures is the most sensitive parameter affecting protective performance. Additionally, the relative resistance between the vessel and the composite fender affects the main dissipation path of the impact energy. Generally, the composite fender is effective in protecting the bridge pier and vessel, including impact force reduction, superior energy dissipation, and extension of impact duration.