共振是桥梁结构应当避免的一种现象,风、人群、地震等外荷载均与桥梁结构产生过共振现象从而造成严重后果,文章对不同体系斜拉桥车桥耦合共振效应进行研究,提出了车流作用下的斜拉桥车桥共振效应判定方法,对漂浮体系、半漂浮体系等斜拉桥进行了共振效应的可能性与判定条件分析,并给出了相关算例。结果表明:等间距车流对桥梁的激扰频率主要由相邻车辆时间间隔决定,漂浮体系斜拉桥由于基频较低,在等间距车流作用下存在车桥共振的可能性,其余体系斜拉桥车桥共振概率极低;建议漂浮体系斜拉桥运营时可在桥面各车道纵向不同位置分别设置减速标志,将车流“打乱”,减小共振概率。
Resonance is a phenomenon that should be avoided in bridge structures. There are numerous cases of bridge resonance caused by wind, pedestrian and earthquake, leading to serious conse- quences. In this paper, the response of vehicle-bridge coupled vibration of different types of cable- stayed bridges is analyzed and the judging method under traffic flow is presented. Then the possibility and criterion of the response of the resonance of floating system and half floating system are analyzed. The related numerical example is also given. The results show that the interval time between the vehi- cles is the main influence factor of the excitation frequency under the condition of the equally spaced traffic flow. Cable-stayed bridge of floating system has the relatively high possibility to cause vehicle bridge resonance for the reason of the low basic frequency under the equally spaced traffic flow, com- paring to the other types of cable-stayed bridges. An appropriate way to reduce the possibility of the resonance is to set up the traffic signs of deceleration at different longitudinal positions.