Study On The Seismic Performance Of Large Span Continuous Rigid Frame Bridge With Corrugated Steel Webs And Double Thin-walled Piers

As a lifeline project in China’s traffic engineering,the demand for seismic performance of bridges is getting higher and higher.On the basis of existing codes for seismic fortification according to three levels,engineers often increase seismic grade in seismic design of bridges as seismic fortification standard of bridges.With the continuous development of our country’s infrastructure construction,the demand for seismic performance of bridges is getting higher and higher.In order to ensure the continuous traffic after the earthquake,experts and scholars gradually put forward the goal of seismic performance of bridges in high-intensity areas that can be repaired under large earthquakes without collapse.The double-thin-wall pier corrugated steel web bridge is not only popular among experts and scholars in the field of engineering seismic resistance in the form of new upper structure with light weight,durability and simple construction,but also the flexible pier type combined with it is an ideal pier for large-span bridges.Northwest China belongs to high-intensity seismic area in China,so it becomes very important to analyze seismic response of double-thin-wall pier corrugated steel web bridge under frequent and rare earthquakes.In this paper,the development and research status of seismic performance of corrugated steel web bridges and double thin-walled pier continuous rigid frame bridges are firstly summarized.Several seismic response methods are introduced and the evolution of bridge seismic design method is summarized.Taking Shichuan Yellow River Bridge(90+160+90)m double thin-walled pier corrugated steel web continuous steel structure bridge as engineering background,the MIDAS CIVIL finite element model is established.The main research contents are as follows:(1)Based on the actual engineering situation,the pile-soil bridge finite element model is established to verify the validity of the model and analyze the dynamic characteristics by comparing the seismic codes.(2)The equivalent pre-stressed concrete bridge of Shichuan Yellow River Bridge is established based on the principle of equivalent shear force,and the dynamic characteristics are compared and analyzed.On this basis,the seismic responses of the two bridges are compared and analyzed by time-history response analysis method.Acceleration and displacement time history analysis is performed for longitudinal,transverse and vertical seismic wave input of the two bridges respectively.The improvement of seismic performance of corrugated steel web bridge is verified.(3)Determine the datum calculation model and study the variation of pier internal force under different pier heights,wall thicknesses and center spacing by time-history response analysis under elastic seismic response.To explore the influence of parameters of double thinwall pier on seismic performance of highway pier.The research shows that the change of pier height and thickness has a great influence on the seismic performance of double-thin-wall pier.The variation of the distance between the centers of the thin wall does not improve the seismic performance.(4)Using nonlinear time-history response analysis,the seismic performance of corrugated steel web bridge and pre-stressed concrete bridge under rare earthquakes is investigated in longitudinal and transverse directions respectively.By analyzing the development position of plastic hinge and the elastic-plastic condition of cross-section fiber,the seismic performance advantage of corrugated steel web bridge under high earthquake intensity is proved by combining internal force and displacement.The location and regularity of plastic hinge of double thin-walled pier in nonlinear seismic response are explored by combining two bridge models.