| Half-through concrete-filled steel tubular arch bridge is widely used in bridge construction because of its beautiful shape,good terrain adaptability,large span capacity and so on.As an important force member,the suspender is connected with the arch rib and the bridge deck system,and the force is more complex,and it is extremely vulnerable to corrosion and fatigue damage.when the damage reaches a certain degree,it is easy to cause the suspender to break and cause major safety accidents.the safety and durability of the suspender directly affect the safety of the arch bridge.Therefore,for the consideration of the safety performance during the use of the suspender,this paper will focus on the damage and fracture of the suspender.The main research contents are as follows:(1)In this paper,taking a half-through concrete-filled steel tubular arch bridge with reinforced longitudinal beam as the engineering background,the bridge models are established by using MIDAS/CIVIL and ANSYS software,and the static and dynamic calculation results of the two models are compared and verified to ensure the correctness of the model.At the same time,MIDAS/CIVIL model is used to analyze the static characteristics of suspender under the action of dead load,vehicle load,temperature load and shrinkage and creep during bridge operation,and the dynamic characteristics under different speed and vehicle weight are analyzed,and the mechanical performance of suspender during service is obtained,which provides a basis for the study of suspender damage and fracture.(2)Based on the damage mechanism of the suspender and the matrix perturbation theory,the change trend of the tension vector of the suspender system after the suspender damage is analyzed,and the hanger damage phenomenon is simulated by using the uniform reduction of the hanger cross-section area according to the above theory.The tension change of suspender system and the law of tensile stress redistribution after single suspender,multiple suspender and whole bridge suspender damage are analyzed by finite element simulation,and the residual bearing capacity of single suspender is evaluated.The results show that the s1#suspender has the least ability to resist damage,and the S13#suspender has the greatest ability to resist damage.(3)Based on the comparative analysis of three commonly used suspender breaking simulation methods,it is determined that the semi-dynamic simulation method is a more suitable simulation method,and the dynamic response analysis of the suspender breaking position,quantity and sequence is carried out with the ANSYS model.The tensile stress and Anchorage point displacement of the suspender system after the suspender breaking are analyzed by means of dynamic magnification factor(DAF)and structural requirement capacity ratio(DCR).The results show that the suspender system tensile stress and Anchorage point displacement are analyzed when single suspender and multiple suspender are broken.Will not cause the rest of the suspender to break.(4)Because the stress of the suspender will increase sharply,and the hanger break will have a greater impact on the adjacent suspender,so the S1#suspender with the greatest ability to resist damage and the smallest S13#sling suspender are selected as the target suspender to carry out the corresponding damage safety analysis,that is,after the target suspender is damaged to varying degrees,the impact effect caused by the fracture of adjacent single or multiple suspenders on its safety performance is analyzed.At the same time,the whole bridge model without reinforced longitudinal beam was established,and the S1#suspender was selected for damage safety analysis to discuss the influence of reinforcement on the safety performance of damaged suspender. |
