双薄壁墩刚构矮塔斜拉桥地震时程响应分析

为了研究双薄壁墩墩高和壁厚组合的厚高比对双薄壁墩矮塔刚构斜拉桥地震反应的影响，以甘肃天水国际陆港市政道路工程渭河五号桥（75+126+75）m连续刚构矮塔斜拉桥为研究对象，依托Midas Civil软件建立全桥空间有限元分析模型，利用非线性时程分析法，对五种不同工况组合的厚高比形式下的建模结构的地震响应进行对比。对比结果表明，墩高相比壁厚更能影响墩顶纵向弯矩，厚高比越大，对纵向弯矩的贡献值越小。各厚高比的塔身最高处索鞍横向剪力小于最低处索鞍横向剪力，工况厚高比越大，墩顶横向剪力越小。塔墩梁固结附近的横向剪力明显大于其他各关键位置的横向剪力。除主跨跨中位置处竖向外移需要注意外，梁端竖向位移突出，由于刚构斜拉桥的特殊性，在实际工程中应在此种结构的边墩处设置合适的减隔震装置或支座以减小地震响应影响。

Seismic Time-history Response Analysis of Low-pylon Cable-stayed Bridge with Double Thin-walled Piers

In order to study the effect of the thickness-to-height ratio of double thin-walled pier height and wall thickness combination on the seismic response of double thin-walled pier short tower rigid frame in cable-stayed bridge, China, taking the Wei River No. 5 Bridge (75 + 126 + 75) m continuous rigid frame cable-stayed bridge with low pylon of Tianshui International Dry Port Municipal road project in Gansu province as the research object, the whole bridge space finite element analysis model is established based on Midas software, and the nonlinear time-history analysis method is used, in this paper, the seismic responses of the structures with different thickness-to-height ratios under five different working conditions are compared. The results show that the height of pier has more influence on the longitudinal moment than the wall thickness, and the larger the ratio of thickness to height, the smaller the contribution to the longitudinal moment. The transverse shear force of the saddle at the highest part of the tower is less than that of the saddle at the lowest part. The transverse shear force near the consolidation of pylon pier and beam is obviously larger than that at other key positions. In addition to the vertical displacement of the middle of the main span, it should be noted that the vertical displacement of the beam end is prominent, in order to reduce the influence of seismic response, appropriate isolation devices or supports should be installed at the side piers of such structures in practical engineering.