Study On The Seismic Performance Of Prefabricated Steel Truss-concrete Composite Continuous Rigid Frame Bridge

This paper is financed by the application of basic research projects of the Ministry of transportation entitled with "Basic theory research of large span steel truss-concrete composite continuous rigid frame bridge"(Project number:2013 319 814 040).To increase the span ability and overcome the disadvantages of the traditional prestressed concrete continuous rigid frame bridge,Professor Zhou Zhixiang proposed a prefabricated steel truss-concrete composite continuous rigid frame bridge(PSTC).In this paper,a PSTC continuous rigid frame bridge with span arrangement of 193+386+193m is assumed as the engineering background,by using the nonlinear time history analysis method,the seismic performance of PSTC continuous rigid frame bridge is studied,and the main research work includes:? The main characteristics,structure and construction process of PSTC continuous rigid frame bridge is introduced.The static analysis is carried out,combined with the corresponding requirements,the static calculation results are verified,results proved the feasibility of PSTC continuous rigid frame bridge in the static range.? According to the particularity of the bridge structure,the method to establish a suitable nonlinear dynamic model of PSTC continuous rigid frame bridge is explored.The nonlinear characteristics of precast deck panel,seam and pier is simulated by using different PMM plastic hinges,and the plastic hinge properties are calculated through UCfyber;besides,nonlinear spring element is used to simulate the nonlinear characteristics of PCSS shear connectors,which nonlinear characteristics is calculated according to model test and the finite element analysis.? By using nonlinear time history analysis method,the parameters influencing the seismic response of PSTC continuous rigid frame bridge is discussed.Three cases of seismic wave input(Ex + 0.3Ey + 0.3Ez?+ 0.3ExEy+0.3Ez?0.3Ex+ 0.3Ey+Ez)are planned to acknowledge the seismic response of PSTC bridge,results show that when the longitudinal seismic wave is dominant,under the E2 earthquake action of level 9 earthquake intensity area,finally the top and bottom of the pier section within the range of 10m turn into plastic state;when the transverse wave is the dominant,under E2 earthquake action of level 7 earthquake intensity area,finally within the range of 1/4?3/4 of the side span,deck seam are cracked;when the vertical seismic wave is dominant,under E2 earthquake action of level 8 earthquake intensity area,finally the whole deck panel and seam are cracked.Seam is the weakest part of bridge,which needs to take precautions in practical engineering design.? Longitudinal traveling wave effect of PSTC continuous rigid frame bridge with the main span of 386m is analyzed,in which the earthquake action is E1 with the basic peak acceleration of PGA=0.3g.By using EI-Centro wave as the longitudinal input,effect of six wave traveling speed ranges from 100m/s to 1600m/s are analyzed.The results show:For the span of PSTC continuous rigid frame bridge is about 386m,when the traveling wave velocity is greater than 400m/s,influences of the traveling wave effect to the bridge displacement response should be considered;when the traveling wave velocity is less than 200m/s,influences of the traveling wave effect to the bridge internal force response should be considered;when wave velocity changes from 200m/s to 400m/s,the seismic response of the PSTC bridge can be analyzed through uniform excitation with small error.