Limitations and Improvement Thinking of Code-Prescribed Static Analysis Method for Vessel Impact Design of Bridge Structures

Analysis methods are essential for the vessel-impact resistant design of bridge structures, which have respect to reasonably determine the demand and capacity of bridge structures subjected to vessel impact loading. For this reason, a number of researchers have paid their attention to develop the reasonable analysis method for vessel-bridge collisions in the past twenty or thirty years, facilitating the development of the design methodology of bridge structures under vessel collisions. For example, with the development of the nonlinear contact-impact finite element (FE) technique, the FE-based method has been developed and used in engineering practices. Also, some simplified methods have been proposed based on the nonlinear contact-impact FE technique. Although these methods are capable of clarifying the interaction mechanism between vessels and bridges, they cannot be used to replace the code-prescribed static analysis method due to computational efficiency. Hence, this paper places emphasis on the code-prescribed static analysis method. First, the limitation of the code-prescribed static analysis method is presented by comparing their results with the dynamic results. Then, based on the two degrees of freedom (DOF) system, the equivalent static analysis method considering the load pattern is investigated through the shock spectrum analysis method. This work provides an idea for improving the code-specified static analysis method.