Seismic Response Analysis Of Cable-stayed Bridge With Single-plane And Fixed Pier-tower-beam System

As the long-span cable-stayed bridges are the key projects on traffic lines, it is of greatsignificance to ensure their earthquake resistance safety. The cable-stayed bridges withsingle-plane and fixed pier-tower-beam system are not common when the main span reachesto300meter, so the structural style of the Fanhe Harbour cable-stayed bridge is very special.In addition, considering its earthquake intensity of the situation and significance, it is veryimportant to analyze its seismic response.(1) Several common seismic response analysis methods of cable-stayed bridge wereresearched and summarized in this passage. Moreover, dynamic equilibrium equations of thestructure under multiple-support excitations were deduced.(2) The proposed improved Kriging–based response surface method was utilized toidentify the parameter of the Fanhe Harbour bridge. Then, setting up its dynamic model byANSYS. After completing the modal analysis, the first300natural frequencies and dynamiccharacteristics of the bridge were acquired.(3) Using the design acceleration response spectrum of Guidelines for Seismic Design ofHighway Bridges(JTG/T B02-01-2008) as input, the seismic response spectrum analysis ofthe Fanhe Harbour bridge subjected to uniform excitation was done. Because of theconcentrated frequency spectrum, modal combination were done by the CQC method. Inorder to compare with the response spectrum analysis, the time history analysis method wasused to analyze the seismic response of the Fanhe Harbour bridge subjected to uniformexcitation.(4) Under the longitudinal and vertical seismic excitation at the same time, thelongitudinal displacement of the tower top which are getting from the time history analysisand the response spectrum analysis are3.20E-02m and2.50E-02m respectively, the momentof the tower bottom which are getting from the time history analysis and the responsespectrum analysis are1.21E+05kN.m and7.17E+04kN.m respectively. Under the horizontaland vertical seismic excitation at the same time, the horizontal displacement of the tower topwhich are getting from the time history analysis and the response spectrum analysis are1.73E-01m and1.12E-01m, respectively, the moment of the tower bottom which are gettingfrom the time history analysis and the response spectrum analysis are8.16E+04kN.m and5.64E+04kN.m respectively.(5) For the seismic response of long-span cable-stayed bridges are greatly influenced bythe spatial variation of ground motion, seismic response analysis of the Fanhe Harbour bridge under non-uniform excitation was conducted.