The Effect Of The Geometric Parameters On The Curved Girder Bridges’ Modal And Vibration Mode Direction Factors

With the rapid development of the urbanization, curved girder bridge has got more and more utilization in the city and joint of city-to-city. Scholars have done many researches on static and dynamic analysis of curved girder bridge, but through studying on the vital parameters which have effects on dynamic property and vibration mode direction factor of curved girder bridge, we still failed to find related rules. To solve this problem, this thesis focuses on analyzing the effect on dynamic property, the reasonable number of vibration mode and vibration mode direction factor of curved girder bridge by the change of some parameters.Taking two-span curved girder bridge with box-girder section as research object, this paper, using finite element software, establishes different models and analyses the influence on dynamic property of curved girder bridge by the change of central angle, radius of curvature and the ratio of span to radius. Results can be gotten as follows:(1) The change of central angle has biggish effect on vibration mode of curved girder bridge which is dominated by adverse torsion. With the increase of the change of central angle, vibration mode of curved girder bridge, which is dominated by torsion, appears later and later, also less and less. With the increase of the change of central angle, the vertical bending direction factor and the longitudinal shift direction factor have the trend of overall increase; the torsion direction factor and the lateral bending direction factor have the trend of overall decrease.(2) The change of radius of curvature in some range has some effect on vibration mode of curved girder bridge which is dominated by adverse torsion. With the increase of radius of curvature, vibration mode of two-span curved girder bridge, which is dominated by torsion, appears more and more. With the increase of radius of curvature, the vertical bending direction factor has the trend of overall decrease and the torsion direction factor has the trend of overall increase; the longitudinal shift direction factor and the lateral bending direction factor have no obvious change; at the same time, the vibration mode dominated by longitudinal shift appears later and later.(3) With the increase of the ratio of span to radius, the vertical bending direction factor has the trend of overall increase and the torsion direction factor has the trend of overall decrease; the lateral bending direction factor has the trend of slight decrease and the longitudinal shift direction factor has the trend of slight increase; the vibration mode dominated by lateral bending appears earlier and earlier, with less and less steps; the vibration mode dominated by longitudinal shift appears earlier and earlier, with more and more steps.