Safety Assessment Of Different Cross-section Piers Scratched By Ships

The traditional way to simulate ship-bridge collision is:to build a precise finite element model to reproduce the ship-bridge contact, the impact force, the damage deformation and the time history of energy absorption, trying to realize the simulation of ship-bridge collision process with real situations. Generally the object of ship-bridge collision is the navigable span with anti-collision facilities. However as for many non-navigable spans without anti-collision facilities whose designed ship collision force is lower passed by the small ships or ships out of control, the piers might be scratched by these ships. In the above cases, the piers usually are scratched rather than a head-on collision. Therefore threat for non-navigable span piers from the scrape can not be ignored, and the research on the ship-bridge collision in non-navigable span is necessary. So the aim of the research is to study the capability to maintain normal condition of different cross-section piers in non-navigable span scratched by ship, and also give the safety evaluation for the scratched piers. The main contents of the research are as follows:①Based on extensive literature research, the experiment method and study conclusions of ship-bridge collision are presented in the dissertation, giving a brief explanation on the research necessary of the ship-bridge collision for different cross-section piers in non-navigable span. And two common types of pier section (round section piers and rectangular section piers) are selected as the objects for the research.②With a finite element model of a bridge pier scratched by a ship, the effect of distance between ship axis and the scrape point, the angle between ship axis direction and the tangential direction of the collision point were studied, and then a safety assessment was given.③With the simulation of ship-bridge scratch process with different tonnage ships (50tons,150tons) and different cross-section (round and rectangular) piers, a parameter study of the cap beam displacement, the collision point displacement and kinetic energy was conducted. And through the parameter study, discussed the pros and cons of the two cross-section piers, and then a safety assessment was given.④With different friction factors in the simulation, assessed the ability of scratched round cross-section pier to keep normal service condition, and then a safety assessment was given.⑤With different angles between the movement direction of the ship and the transverse direction of the bridge in the simulation, assessed the ability of different cross-section scratched piers to keep normal service condition, and then a safety assessment was given.