Research on Wind Induced Response of Long-Span Continuous Rigid Frame Bridges in Steep Valley Terrain
In order to solve the problem of structural vibration during the construction of continuous rigid frame bridges in steep valley terrain,the Xiaoyaoguang Extra Large Bridge of the PPP project on the Jianhe to Liping Expressway in Guizhou Province was taken as the research object.The wind speed field in the valley terrain,maximum wind induced structural acceleration and vibration mode response characteristics during the double cantilever construction stage were studied using on-site measurement methods.The results show that there are differences in wind speed at different monitoring points,and valley occlusion and sudden changes in river channel width can affect wind speed and direction.The steep valley terrain of Wuxia River exhibits obvious turbulence phenomena;in the maximum double cantilever construction stage,the vibration of the bridge structure is mainly low order vibration,with low transverse and longitudinal bending stiffness and weak wind resistance.Wind load has a significant impact on the overall stability of the structure;the damping ratio composition of large-span continuous rigid frame bridges is complex,with measured damping ratios ranging from 0.2 to 0.8.The distribution of damping ratios in their respective frequencies is uneven.The damping ratio of low natural frequencies and low order modes is relatively large,while that of high natural frequencies and high order modes is relatively large.
valley terrainhanging basket constructioncantilever methodlarge-span bridgewind loaddynamic response
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