Research On Design Impact Spectrum And Reliability Of Vessel-bridge Collision

With the increasing number of bridges across the sea and across the river and the rapid development of the water transportation industry,the collision accidents between vessels and bridges occurred frequently.The collision between vessels and bridges will not only cause huge economic losses,but also affect the service life of the bridge,the safety and seismic capacity.Therefore,in the early stage of bridge design,the safety problem of the collision between vessels and bridges is not to be ignored.In this paper,the safety problem of bridge collision is studied,and the design impact spectrum method for vessel collision is proposed.Based on the analysis of the factors affecting the reliability of bridge collision,the probability model of each factor is proposed.Based on the reliability theory,the reliability of bridge collision is analyzed by the methods of moments based on finite element analysis.The specific research contents are as follows:(1)By reading a lot of domestic and foreign literature,surveys of study on the design and reliability of vessel-bridge collision are reviewed.Aiming at the existing problems in the design specification of vessel-bridge collision,this paper proposes the idea of design impact spectrum for vessel-bridge collision and gives specific research content.Aiming at the redundancy and complexity of method for calculating the reliability of vessel-bridge collision,the specific technical route for the calculation of the failure probability of the vessel-bridge collision based on the reliability theory is given.(2)Based on the idea of statistical analysis,the impact spectrum of vessel collision design with universal laws is given.The calculation theory and fitting process of design impact spectrum of vessel collision are elaborated in detail,and the specific formula and application method of design impact spectrum of vessel collision are given.(3)According to the vessel collision accident,the failure mode of the bridge structure is summarized.The limit state performance function under various failure modes is given.Theprobability model of each factor that affects the performance function is explored.In view of the large discrete type for vessel tonnage,it is difficult to describe this characteristic with common probability distribution.A probability model of unknown tonnage is proposed.In view of the implicit and nonlinear characteristics of the limit state function of the vessel-bridge collision and the limitation of the traditional reliability analysis method to solve the problem,the reliability of vessel-bridge collision is analyzed by the methods of moments based on finite element analysis.This paper gives the flow of the methods of moments of bridge reliability calculation based on the finite element analysis.This method greatly reduces the computation times of finite element,and improves the efficiency of bridge structure failure probability calculation.(4)Taking a bridge in Guangzhou as an example,the failure probability and reliability index of bridge structure are calculated by the methods of moments of bridge reliability calculation based on the finite element analysis,which provides reference for the application and development of this method in practical engineering.Finally,the prospects for the study of design impact spectrum and reliability of vessel-bridge collision are presented,and points out the further research direction of design impact spectrum and reliability of vessel-bridge collision.