Arch Bridge Suspender Cable Force Test And Its Seismic Capability Assessment Method Research

Suspender undertakes the important task which is load transfer of the half-through or through arch bridge.As to the safety of half-through or through arch bridge,suspender is one of the core members.In recent decades,earthquake activity is frequent,suspender damage and broken lead to bridge collapse problem frequently.Suspender cable force test and seismic capacity assessment has been concerned by scientists.Considering the importance and urgency of suspender problem,this paper will take a research basing on the achievements of those predecessors by using the method of theoretical derivation,numerical fitting method and the finite element method in order to study suspender cable force test and seismic capacity evaluation methods.Mainly works are as follows:(1)Survey statistics of half-through and through arch bridge suspender diseases in recent decades has been done in order to analyze the causes of suspender diseases,finding the main reason of suspender have prone to cracking of sleeve,water seepage,corrosion and broken wires and other diseases are that the suspender is under high stress and fatigue loads in a long time,protective equipment damage seepage and fatigue damage of steel wire.(2)Through detailed statements of the suspender cable force test method,beam vibration theory and chord vibration theory,introducing the dimensionless parameters and using the method of theoretical derivation and numerical fitting,relation between suspender cable force and frequency is deduced;establishing suspender finite element model,the formula derived from the validation accuracy,shows the flow chart of formula of practical application,and tested in actual engineering.(3)Through detailed statements of seismic response analysis methods of bridge,the bridge seismic capability assessment method and the earthquake damage criterion,the damage form of suspender has been analyzed,and based on the theory of suspender design and the dual failure criteria,establishing suspender of seismic capability assessment model with different damages of various levels.(4)Using established different injured suspender aseismic capability assessment model,evaluating and analyzing the suspender of Yong He bridge in Nan Ning aseismatic capability,establishing finite element models of Yong He bridge with ANSYS software,assuming that the boom is in six different damage states,with elastic modulus of simulation suspender subtraction process of different degrees of injury,respectively proceeding seismic time history analysis,and then calculating damage index to evaluate suspender.The conclusion is that short suspender is easier to be damaged than the long one under the same seismic load and the same injury;when 9-level earthquake occurs,the damage 0.5Es short boom and at a location 1/4 suspender are in medium damage state;thanks to its big safety coefficient within its design,suspender with certain damage can still ensure the safety of the structure under earthquake load.