索支承体系桥梁弯扭频率的敏感性分析

The sensitivity analysis of bend and wrest frequency for cable-supported bridge beam

在对索支承体系桥梁主梁抗风研究中,弯扭频率在桥梁抗风实验中是十分重要的衡量桥梁动力性能的指标。本文主要以在建的上海长江大桥和西堠门大桥为背景工程,分析了引起索支承体系桥梁主梁质量、主梁刚度、计算索力、桥塔刚度变化的原因和幅度。并依据这些因素可能的变化幅度,重点研究了这两座有代表性桥梁弯扭频率对这些因素的敏感性。主要得出如下结论:主梁质量、主梁刚度的变化对索支承体系桥梁弯扭频率影响较大,计算索力、桥塔刚度的变化对索支承体系桥梁弯扭频率影响相对较小。

In the wind-resisting test of cable-supported bridge beam, bend and wrest frequency is an essential index to estimate dynamic performance of bridges. Based on projects of the Shanghai bridge over Yangtse River and the Xi Houmen suspension bridge, the variability of the beam mass, beam rigid, bridge tower rigid and original cable force are studied in this paper. The sensitivity of the bend and wrest frequency to these factors is stressed. The results indicate that the beam mass and rigid has more influences than the original cable force and bridge tower rigid on the bend and wrest frequency of the cable-supported bridge beam.