研究结论:通过建立双塔单索面部分斜拉桥的动力分析力学模型,运用有限元法对部分斜拉桥进行了动力特性与地震反应时程分析。模态分析表明:双塔单索面部分斜拉桥的第1振型为主梁对称竖向弯曲,第一自振频率比漂浮体系的斜拉桥大,因此受竖向地震、风和车辆振动的影响较大。研究了在多遇地震作用下桥结构的内力和变形规律,分析了部分斜拉桥的抗震性能,研究表明:部分斜拉桥在50年超越概率为10%的多遇地震作用下满足抗震设计规范的要求。

Research conclusions:Through establishing the dynamic analysis mechanic model for twin towers single cable –stayed bridge, the dynamic characteristics and temporal process of earthquake are analyzed for twin towers single cable –stayed bridge with finite element method. The modal analysis shows the first modal of twin towers single cable -stayed bridge is the vertical symmetrical bend ofmain beam, with bigger self -vibration frequency than the floating cable –stayed bridge, so the twin towers single cable -stayed bridge ismuch influenced by vertical earthquake, wind and vehicle vibration. The internal force and deformation law of the structure of the bridges encountered many earthquakes are studied, and the seismic performance of the cable -stayed bridge is analyzed. The study shows some cable –stayed bridge canmeet the seismic requirement stipulated in the design code under effect of encount eringmany earthquakes with the transcendental possibility of 10% in 50 years.