Steel Fender Limitations and Improvements for Bridge Protection in Ship Collisions

Steel fenders are widely used in China to protect newly constructed bridges from collapse when struck by ships. In fact, steel fenders are more commonly used in China than other types of bridge protection systems. However, few studies have been conducted to verify the performance of these fenders in a collision. To begin this study, a conventional steel fender was investigated using high-resolution finite-element (FE) analyses of ship–bridge–fender collisions. The limitations of the conventional fender were clearly demonstrated. In particular, when a bridge equipped with the steel fender was subjected to a high-energy collision with a vessel, the impact forces and dynamic responses were greater than on those with no fender. Thus, the authors propose a novel fender design composed of steel and concrete to overcome the limitations of the conventional steel fender. In the proposed fender, the panel that comes in direct contact with the errant ship is made of reinforced concrete, and the inner steel members are designed to absorb the impact energy. Detailed FE models were generated to evaluate the performance of the new steel–concrete composite fender under ship-impact loading. Numerical results indicate that the protective performance of the proposed fender is superior to the conventional steel fender.