Research On Impact Spectrum For Vehicle-Bridge Collision

In the process of modern transportation,the traffic accidents happen frequently and bridge pier suffer a lot from it.An equivalent static method is employed in most codes and specifications for vehicle collision design of bridges,in which the dynamic nature of vehicle-bridge collision is ignored.Finite element method(FEM)is widely used for research on vehicle-bridge pier collision.It always takes a long time to finish analysis of collision numerical when FEM is used.So FEM isn't popular in engineering practices.Statistical classification,calculation method and application suggestion of vehicle-bridge collision impact spectrum were proposed by referring to the concept of the earthquake response spectrum.The impact spectrum was excepted to be had advantages of dynamic time history analysis method and equivalent static method.This study presents three research results as follow: Result oneAccording to classification criteria of road vehicle,seven type vehicles were selected to be used in this research.This paper established seven vehicle finite element models and vehicle colliding with rigid wall is used and works as the source of data processed and researched.Contact boundary,friction and coupling,between the part of model,were taken into consideration in every model.Result twoThrough numerical simulations of the vehicle-rigid wall collision,63 sections of impact force time histories associated with different cases were obtained.The mathematical expressions of impact force peak and collision peed were developed by fitting,all kinds of vehicle,distribution of impact force peaks.Result threeThe analysis method of vehicle-bridge collision impact spectrum was proposed by referring to the concept of the earthquake response spectrum.The displacement amplification factor of a single-degree-of-freedom(SDOF)system with different period was calculated under the excitation of impact force time histories.Based on the statistical regularities of period and displacement amplification factor,mathematical expressions of the impact spectrum were developed.Last but not least,application method of the impact spectrum was proposed,based on above mentioned works.The dissertation has obtained a preliminary achievement that the calculation method of vehicle-bridge collision impact spectrum.It has theoretical guiding significance and engineering practical value,though it is a primary exploration on the design of vehicle-bridge collision.