Dynamic Response of Cable — Stayed BridgesTravelled by Trains

• Main Authors: Hsiao, Chi-Chin, 蕭吉謹
• Other Authors: Yang, Yeong-Bin
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/12894674208413535632

博士 === 國立臺灣大學 === 土木工程學研究所 === 90 === Cable-stayed bridges have been widely accepted by bridge designers due to their aesthetical appeal and economy in construction. To satisfy the requirements for structural safety, the mechanical behaviors of the cable-stayed bridge under loading conditions should be investigated in depth. In the literature, the cables of a cable-stayed bridge were usually idealized as two-force members in the analysis with an equivalent elastic modulus to account for the sag effect of the cable. Such an idealization makes the analysis simpler; however, it is inappropriate if the effects of vibration modes of the cables are of concern. There is a large variety of investigations on the dynamic response of conventional box-girder bridges to the passage of trains. In contrast, the studies on the dynamic interaction between the cable-stayed bridge and moving trains appear to be comparatively few. Because the cable-stayed bridge usually has higher flexibility and thus lower natural frequencies, it is likely that the phenomenon of resonance occurs as the train passes over the bridge at lower speeds. The operation speeds of the train should keep away from those at which the resonance of the cable-stayed bridge may occur. The impact response of the bending moment of the cable-stayed bridge induced by the moving train is larger than those for the axial and cable forces, which should be taken into account in design practice. In the thesis, a procedure for analyzing the dynamic interactions between the vehicles and the cable-stayed bridge has been developed based on the nonlinear theory of structures using the finite element method, in which the geometric nonlinearity of the cables, bridge deck and pylon(s) and the dynamic properties of the vehicles are included. The proposed procedure was then employed to perform the time-history and parametric analyses of the train-bridge interaction system considered. Several typical cable-stayed bridge models were used to investigate the effects of the train speed and vibration modes of the cables on the impact response of the cable-stayed bridge.