Research On Risk Assessment And Bridge Protection Facilities Of Bridges Under Vessel Collisions

Vessel collision becomes a serious security issue, as bridges are built across navigation waterways. Since 1980s, China has constructed and planed to build a large number of bridges across waterways, while shipping vessels are also developing fast. These two factors make bridge engineering practitioners address the problem of ship-bridge collision safety analysis and anti-collision design theory. In study of basic theory of ship-bridge collision risk assessment, Chinese scholars have conducted preliminary researches and explorations. Whereas the depth and comprehensiveness are inadequate, and it can not adapt to a large number of bridge constructions. Passive anti-collision facility is an engineering measure to reduce the risk of ship-bridge collision. It should be carefully selected according to specific circumstances because of its various forms and different properties. Thus, further study for the risk assessment of ship- bridge collision and anti-collision facilities is necessary.There are a lot of research methods on risk assessment of ship-bridge collision, which probabilistic risk assessment can quantify the risk of ship-bridge collision, this paper will use the method to analysis the risk of ship-bridge collision. The collision between ship and anti-collision equipment is a complex and a complicated non-linear problem, which can not be thoroughly solved only rely on classical collision theory. With rapid development of nonlinear finite element technique and computer hardware level, computer simulation methods can be used to solve such problems.One of the priorities of this article is to study the model of the probability of ship-bridge collision. On the basis of comparatively analyzing the results of previous studies, I summarize and deepen the understanding of existing knowledge to give personal opinions; The other is the collision analysis of collision protective device. The protection device of the main pier of a bridge collision is analyzed by using ANSYS/LS-DYNA. The main results of this text are as follows:(1) Comparatively analyzed the probability model of both home and abroad, fully considered the impact factors of ship-bridge collision probability, the corresponding impact factors are introduced to modify the ship collision probability model.(2)Complete the calculation ship collision probability of both long side and short side of rectangular piers.(3)Considering the actual distribution of impact angle, modify the ship collision force calculation formula of AASHTO.(4) Connected the classical theory of ship-bridge collision and the calculation features of ANSYS/LS-DYNA, then proposed some important notices which need to be focused on when solving the collision problem by using ANSYS/LS-DYNA.(5)A ship collision risk assessment of a bridge over Yangtze River is carried out. Calculate the probability of ship collision with the pier. Design collision protective device rationally, the collision process of a 5000DWT ship crashing to the collision protective device at a speed of 3.0m/s, is simulated by using the ANSYS/ LS-DYNA. Some discussions are done for the corresponding calculation results.