Experimental Study On Dynamic Characteristics Of Single-Box Multi-Cell PC Composite Girder Bridge With Corrugated Steel Webs

The PC composite box-girder bridge with corrugated steel webs,which webs adopted corrugated steel plate instead of concrete,is a new kind of composite steel-concrete structure.In recent years,the new structure has been concerned widely and developed rapidly,because of it's light weight,small longitudinal stiffness and high shear strength,so that it could reduce the internal force of dead load effectively,improve the efficiency of the prestressed stress and solve the problem of webs cracking.To cover the shortage of study in dynamic characteristics of the structure,based on the non-navigable span bridge of the Chaoyang Bridge in Nanchang Jiangxi province,a comprehensive study and analysis was taken through scale-size test model bridge,finite element analysis and real bridge dynamic test.Firstly,this paper reviews the structural and mechanical characteristics,development and research status of the composite box-girder bridge with corrugated steel webs;And introduces briefly the process of building the bridge bending and torsional vibration equations,the solution methods of the dynamic characteristic equations and two algorithms of modal parameter identification.A three spans scale-size model bridge with corrugated steel webs was designed and constructed,which based on the prototype bridge and the geometric similarity ratio is 1:10.Then two sets of mode analysis system were used to carry on the dynamic experiment for the model bridge,and previous four natural frequencies and corresponding modes were identificated,which the correctness and precision of finite element could been examined.The finite element model of single-box multi-cell PC composite girder bridge with corrugated steel webs was builted,and analyzed the difference of box-girder dynamic characteristics between corrugated steel webs and concrete webs.Furthermore,this paper focus on the effect on dynamic characteristics from the structure parameters and geometric parameter.The mode analysis method based on ambient excitation was used to identify the modal parameter identification of the real bridge,and comparison the measured results between model bridge and real bridge to examine the correctness the model bridge;While the local vibration of the bridge deck of the vibration experiment was taken,and comparison with finite element analysis,and study the influence factors of the structure local vibration.