Dynamic Response Analysis For Suspenders Failure Of Arch Bridge And Research On The Safety Countermeasures

The importance of the suspender as a key component of the half-through and through arch bridge is obvious,and due to the existence of various uncertain factors,the suspender is likely to break out in advance.While when the suspenders of arch bridge break suddenly,the safety of arch bridge is not taken into consideration thoroughly in the current suspender design theories.But the existing theory and technical means could not make accurate decision about when the suspenders will fracture.As a result,bridge damaged or destroyed accidents caused by suspender fracture have occurred occasionally.Therefore,this paper aiming at single suspender tied arch bridge,based on the previous studies of failure safety of suspenders of arch bridge design,makes analysis and researches to achieve the goal that suspender cracks but not bring damages to the bridge.It can guarantee the normal running of arch bridge and provide sufficient time to maintain the bridge.This paper,combining with concrete-filled steel tubular arch bridge,makes researches on the influence the suspender fracture made on the arch bridge and explores and analyzes the methods of failure safety of suspenders of arch bridge design.The main contents are as follows:(1)Summarize the causes and countermeasures of the suspender fracture,analyze the research status of the safety of the arch bridge's suspender fracture safety,and clearly designate the purpose and significance of failure safety of suspenders of arch bridge design.(2)Elaborate the approaches to achieve failure safety theory and construction.Based on the idea of multiple load paths,two kinds of failure safety design methods,which are mainly for single suspender system,are introduced and applied to the existing arch bridge as well to carry out further researches.(3)The semi-dynamic simulation method was applied to simulate the response of the arch bridge when the suspender fracture is taking place.In this paper,the impact effect of arch bridge subjected to short hangers and long hangers is analyzed respectively,and the safety of the ordinary single suspender arch bridge in the process of suspender breaking is studied,so as to find out the unfavorable load places during suspender fracturing.The results show that the suspender fracture may cause the longeron and beam of the bridge failure to be jointed as well as bridge damaged.(4)Improve the single suspender system and apply the improved failure safety system to the Maocao Street Bridge,modeling and analyzing the safety of arch bridge with failure safety system.As the analysis results shown,the improved failure safety system can enhance the safety performance of the arch bridge effectively,and will not lead to bridge damaged or destroyed.In this way can prove the rationality of the des ign principles of failure safety suspender.(5)In this paper,the reasonable design of the failure safety of single suspender system was discussed,the conclusions can provide some reference value for the design of failure safety suspender of the single suspender tied arch bridge.