The Design Method Research Of Bridge Anti-collision Facilities Based On The Matching Stiffness

In this paper,we have been systematically studied the dynamic response of ship bridge collision through the finite element analysis software on the basis of forefathers' research.It consider the ship,anti-collision facility,pier as a system to analyze,and put forward a simplified dynamic analysis method based on the "System stiffness".Considering the rigidity of the anti-collision facilities on the impact of ship collision force.So we get reasonable stiffness ranges for different anti-collision facilities.At the same time put forward a way that based on the idea of “matching stiffness” for the design of anti-collision facilities.And it is verified on the performance of the anti-collision facilities through the practical engineering project.The main research results are as follows:(1)It calculates equivalent stiffness of 800 DWT ~ 5000 DWT common ship In our country inland.The orders of magnitude of the ship bow stiffness is 104kN/m.It calculates equivalent stiffness of the different structure types of bridge pier.The orders of magnitude of the bridge pier stiffness is 106kN/m.(2)Based on the existing simplified analysis model,the anti-collision facilities is taken into consideration for the first time.It is considered the ship,anti-collision facilities and bridge as a system to build a simplified analysis model based on system stiffness.It get the reduction rate curves of Ship collision force,the compression ratio curves of anti-collision facilities under the different stiffness ratio.And we preliminary determine the scope of the anti-collision facilities reasonable stiffness and propose the simplified calculation formula of the ship collision force based on the "system stiffness".(3)A method based on the “matching stiffness“ is put forward to designing the different anti-collision facilities.The compression stiffness of anti-collision facilities are determined through static numerical simulation.The compression stiffness of the composite fender is about 0.345×104kN/m,The compression stiffness of the composite box is about 0.546×104kN/m,The compression stiffness of the steel box is about1.83×104kN/m,The compression stiffness of the rubber fender is about 0.128×103kN/m.(4)The energy-absorbing capacity for anti-collision facilities is analyzed.In the same calculation condition,the steel box can reduce the rate of ship collision force is9.4%,the composite box can reduce the rate of ship collision force is 39.6%,the composite fender can reduce the rate of ship collision force is 45%,the rubber fender iscompletely crushed.(5)Through the statistical analysis of the results,the reasonable range of the stiffness ratio of the anti-collision facilities is obtained.The stiffn ess of rubber fender is ??0.3,the stiffness of composite anti-collision fac ility is 0.3???0.8,the stiffness of the steel box is 0.8???2.(6)The anti-collision protection design of the bridge is carried out,and the numerical simulation analysis is made based on the SiChuan LuZhou Yangtze river bridge design projects of anti-collision protection.It indicates that the curved composite anti-collision fender can reduce the rate of ship collision force is about 20%,the composite box can reduce the rate of ship collision force is about 40%.These anti-collision facilities are able to effectively reduce the ship collision force,and protect the bridge piers.