中塔刚度对三塔缆索承重桥动力特性影响研究

为研究三塔缆索承重桥中塔刚度的合理取值,本文以马鞍山长江公路大桥和武汉二七长江大桥为例,探究中塔纵桥向弯曲刚度、横桥向弯曲刚度和扭转刚度与三塔悬索桥和三塔斜拉桥的动力特性的关系。研究表明:三塔缆索承重桥某些振型的频率受中塔刚度变化影响较大,并表现为振型频率随刚度放大而迅速增大,然后增大的趋势逐渐放缓,直到趋于稳定值。例如,三塔悬索桥中塔纵桥向弯曲刚度放大5倍时一阶反对称竖弯频率增大37.2%,而100倍时增大为38.0%。

Research on Effects of Middle Tower Stiffness to Dynamic Characteristics of Three-tower Cable-supported Bridge

For research on reasonable value of middle tower stiffness of three-tower cable-supported bridge,this article take Maanshan Yangtze River Highway Bridge and Wuhan Erqi Yangtze River Bridge for example,to study the relationship between longitudinal bending stiffness,lateral bending stiffness and torsional stiffness of middle tower and dynamic characteristics of three-tower suspension bridge and three-tower cable-stayed bridge.The research shows that: certain vibration mode frequencies of three-tower cable-supported bridge are greatly affected by the change of middle tower stiffness,and they increase rapidly at the beginning as the stiffness is magnified,to a stable value with a slowing down trend.For example,first-order antisymmetric vertical bending frequency increases by 37.2% as longitudinal bending stiffness is 5 times magnified,but 38.0% when 100 times.