Research And Optimization Of Seismic Behavior On Through Concrete-filled Steel Tubular Rigid Frame Tied Arch Bridge

Concrete Filled Steel Tubular(CFST)arch bridge has been developed rapidly in our country owing to its characteristics in recent years,such as high bearing capacity,convenience in construction,economic cost and beauty.However,concrete filled steel tubular arch bridge design specifications published time is short,and the bridge design under the guidance of the specification is unknown.Therefore,it is necessary to study the influence of seismic performance on CFST arch bridge with different design parameters,and improve the seismic performance by optimizing the design parameters.Firstly,based on the three dimensional FE model of one rigid-framed through CFST arch bridge which is established in the ANSYS program,the design parameters such as ratio of rise to span,arch rib inclination,steel ratio,number of lateral brace and stiffness of pier are adjusted respectively by the control variable method,in order to analyze the sensitivity of the dynamic characteristics and seismic response comparatively.Secondly,the quadratic polynomial is fitted to calculate the fundamental vibration period of CFST arch bridge which is represented by stiffness ratio of arch and pier.The numerical simulation shows that properly decreasing the stiffness of the pier can greatly improve the natural vibration period of the first order vibration mode and reduce the seismic response,in addition,it can be used to estimate the natural vibration period in the preliminary design.Thirdly,the seismic design is sorted objectively by using method of maximizing deviations for multi-index,so as to achieve the purpose of optimizing seismic performance,and the MATLAB program that other designers can use directly is adopted in the seismic design evaluation.The results show that seismic performances are obviously improved by adjusting the ratio of rise to span and arch rib inclination,The weight coefficient of seismic response index of substructure is larger when the design parameters are evaluated,the internal force of the arch foot and the pier column varies greatly when design parameters are adjusted.And the design of the pier bottom and the arch foot section should be paid more attention.Finally,some suggestions are put forward for the value of seismic design parameters to Specifications for Design of Highway Concrete Filled Steel Tubular Arch Bridges.