矮塔斜拉桥结构动力特性分析

Dynamic Characteristic Analysis of Extra-dosed Cable-stayed Bridge

矮塔斜拉桥具有造型美观、景观协调、技术先进、造价低、施工方便等很多优点,且兼有连续梁与斜拉桥的优点。本文以一座双塔双索面矮塔斜拉桥为工程背景,应用Midas/Civil软件建立其空间模型对矮塔斜拉桥动力特性即自振频率、周期及振型展开研究。研究表明,该桥第一阶振型为全桥纵飘,基频比一般斜拉桥和悬索桥高,全桥抗纵向水平侧移刚度相对较弱;在前10阶振型中,桥塔侧弯的振型出现较多,索面摆动突出,即拉索与桥塔侧向刚度较小。研究结果可为矮塔斜拉桥的设计及施工控制提供参考。

Extra- dosed cable -stayed bridge has many merits such as elegant in design, harmonious landscape, advanced techniques, inferior cost of construction, convenient construction, et al. A extra - dosed cable - stayed bridge with double tower and double cable plane was taken as example for study its natural frequency, period and mode of vibration. The Midas/Civil software was used to making models of this bridge. The study shows that, its first mode of vibration is girder longitudinal floating, and its fundamental frequency is higher than that of the cable- stayed bridge or the suspension bridge, so its lateral displacement stiffness is relatively small; the modes of towers lateral bending is frequently appearance in the first ten previous modes, and the fluctuation of cables has greater amplitude, so lateral displacement stiffness of cables and towers is relatively small too. The result can be reference for the design and construction control.