Numerical Study On Impact Behaviors Of Bridge Pier Collided By Vessels

In recent years,the economic level of our country continues to improve,the water transport industry is also flourishing day by day.At present,the number of large-tonnage and high-speed ships is increasing rapidly.For example,on June 15,2007,a bulk carrier crashed into the pier of the Jiujiang Bridge in Guangdong Province,causing the bridge to collapse seriously.And this kind of accident light will cause the property loss,the serious even can cause the personnel casualty.Therefore,how to avoid the occurrence of such major accidents and how to reduce the serious adverse consequences brought by the accidents,scholars all over the world have invested a great deal of energy in the study of bridge and ship collision.At present,the values of collision force are given by empirical formula in the codes of ship and bridge collision force used in bridge design process in many countries.Today,when the forms of ships are becoming more and more diversified,the empirical formulas used in the existing codes are less considered,and the impact force formulas have not been put forward separately for various types of ships.Not very good to adapt to the actual situation at this stage,there are great limitations.In order to provide a more accurate formula for calculating the collision force of ship and bridge,this paper studies the ship bridge collision of various types of ships by means of finite element numerical simulation.The main works are as follows:(1)The formulas used in the existing codes of collision force for ships and bridges are summarized,and the reference factors and source background of various empirical formulas are analyzed.In this paper,the current research methods and research progress of bridge collision are collected and sorted out,and the types of ships studied in this paper are determined as bulbous bow ship,oblique bow ship and flat bow ship.(2)The finite element simulation software ANSYS-LS-DYNA has been used to established the models of bulbous bow bulk carrier,inclined bow bulk cargo ship and flat bow barge,rigid pier model and reinforced concrete pier model.The processing and simplification of the models are introduced.(3)The collision between bulbous bow bulk carrier,inclined bow bulk cargo ship,flat bow barge and rigid wall is simulated including frontal collision and multi-angle side impact.The influence of bow form difference on impact force is studied,and the results of various empirical formulas are compared.The formula of the maximum impact force of the bulbous bow ship and the oblique bow ship with the angle of collision is obtained.(4)The collision between bulbous bow bulk carrier,inclined bow bulk cargo ship,flat bow barge and rigid pier is simulated,and the dynamic response of ship is analyzed.The collision between a ship and a variety of rectangular and circular piers with different sizes is simulated,and the effects of the geometry and size of the pier on the impact force of the bridge are studied.(5)The collision between bulbous bow bulk carrier,inclined bow bulk cargo ship,flat bow barge and reinforced concrete pier is simulated.The dynamic response of ship and the failure of concrete pier are analyzed.According to the results of finite element calculation,the empirical formulas for simulating the impact force of bulbous bow ship,oblique bow ship and inclined bow ship are fitted respectively.