Estimation method for the fundamental frequency of a three span suspension bridge with asymmetric sidespan
YANG Guo-jun1, 2, DU Yong-feng1 HAO Xian-wu2, LI Zi-qing2, WANG Xiao-ming2
1.Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology, Lanzhou 730050, China;
2.School of Highway, Chang’an University, Xi’an 710064, China
In order to calculate the vibration frequencies of suspension bridges with asymmetric arrangement more rapidly, a threespan continuous girder suspension bridge with doubletower and asymmetric sidespan was taken as research object. The frequency formulas for the 1st vertical and torsional vibration modes were derived based on the RayleighRitz’s method considering the influence of asymmetric sidespan on vibration frequencies, and the generality of the formulas was discussed. The estimation formula for the fundamental frequency of the singlespan suspension bridge was obtained by resolving the limit of some related parameters of the threespan suspension bridge with asymmetric sidespan. Finally, the accuracy of the proposed formulas was examined by the finite element method (FEM). The results show that the errors between the frequencies of 1st antisymmetric vertical and torsional vibration modes calculated by the proposed method and the FEM are 9.2% and 6.7%,while the errors between the frequencies of 1st symmetric vertical and torsional vibration modes calculated by the proposed method and the FEM are 5.0% and 4.4%,which can meet the requirement of design phase. Finally, the influence of the correlation coefficient on the fundamental frequency was discussed. The results indicate that the proposed formulas can be applied to guide the scheme selection and preliminary design of the simplesupported singlespan or the threespan continuous girder suspension bridges with asymmetric sidespan.
杨国俊1,2,杜永峰1,郝宪武2,李子青2,王晓明2. 基于边跨非对称的三跨悬索桥振动基频估算方法[J]. 振动与冲击, 2018, 37(10): 194-201.
YANG Guojun1, 2,DU Yongfeng1,HAO Xianwu2,LI Ziqing2,WANG Xiaoming2. Estimation method for the fundamental frequency of a three span suspension bridge with asymmetric sidespan. JOURNAL OF VIBRATION AND SHOCK, 2018, 37(10): 194-201.
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