DOI: 10.3724/SP.J.1249.2020.04395
高低塔斜拉桥由于双塔不对称,设置辅助墩时需要综合考虑结构的受力状况. 为研究辅助墩设置与大跨度高低塔斜拉桥受力之间的关系,以高低塔斜拉桥为研究对象建立有限元模型,分析辅助墩设置数量及位置对结构产生的影响,基于回归分析拟合单个辅助墩位置变化对结构响应影响的规律,进行单个辅助墩位置优化分析. 研究结果表明,辅助墩的设置有利于改善高低塔斜拉桥的整体受力,可明显降低在移动荷载作用下高塔边跨主梁及高塔的弯矩和位移,但辅助墩的数量增加后,改善效果相比单个辅助墩大幅减弱,设置单个辅助墩是最佳选择. 单个辅助墩位置的改变对高塔边跨主梁及高塔的弯矩和位移影响较为明显,且存在最佳位置,但当辅助墩位置位于一定范围内时,位置改变带来的结构综合响应变化并不明显,受限于外部条件时辅助墩位置亦可根据分析结果灵活选择.
Because of pylons with unequal height, the mechanical characters of the structure should be considered when the auxiliary pier of long span cable-stayed bridge with unequal height pylons is set up. To investigate the relationship between the number and position of the auxiliary pier and the mechanical behavior of long span cable-stayed bridge with unequal height pylons, a finite element model of cable-stayed bridge with unequal height pylons is constructed as the research object, the variation regularity of effects caused by different positions of single auxiliary pier is fitted on the basis of regression analysis. According to the results, the mechanical behavior of long span cable-stayed bridge with unequal height pylons can be improved by setting auxiliary pier and the bending moment and displacement of side span girder and high pylon under live load decrease obviously, but the improvement effect brought by increasing the number of auxiliary pier is greatly weakened as compared with that of a single auxiliary pier. Thus, single auxiliary pier is the best choice with comprehensive consideration. The bending moment and displacement of side span girder and pylon also are influenced by different position of single auxiliary pier, and there is an optimal position. However, when the position of the auxiliary pier changes within a certain range, the variation trend of comprehensive response of the structure caused by the position change is not obvious. When limited by external conditions, the position of the auxiliary pier can be flexibly selected according to the analysis results.
