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鉴于近来修建实腹梁的大跨度斜拉桥的趋势,要求深入研究结构的气弹性问题。在低风速(10～15m/sec)下可发生振幅高达几十厘米的涡脱激振,从桥梁的使用性观点出发,可能是个重要的现象。本文叙述了作用于桥梁模型上的竖向运动的气功阻尼并与模型的横截面形状进行比较。由于梁的横截面形状(包括栏杆和缘石)对抗风稳定性起着重要的作用,从现有的斜拉桥中选择了五种基本梁截面型式和三种栏杆与缘石型式。用新型的装置测量了非定常气动力,每种模型用-4~(?),0°和+4~(?)三个迎风角检测其抗风稳定性。还探测了风力和振幅的非线性特性和二阶谐和锁定现象。最后介绍了末广桥的抗风稳定性。层流条件下的风洞试验表明在栏杆上附加特定折板的情况下具有充分的抗风稳定性。最终,不仅用风洞试验而且由实桥响应的野外观测来检验了紊流效应。
In view of the recent trend of building long-span cable-stayed bridges with solid webs, it is demanded that the problem of aeroelasticity of the structure be further studied. Vortex-induced vibration with amplitudes of up to tens of centimeters can occur at low wind speeds (10-15 m / sec), which may be an important phenomenon from the viewpoint of bridge serviceability. This paper describes the qigong damping of vertical motion acting on a bridge model and compares it with the cross-sectional shape of the model. Since the cross-sectional shape of the beam, including balustures and curbs, plays an important role in the stability of the wind, five basic beam sections and three types of balustrades and curbs have been selected from the existing cable-stayed bridges. The unsteady aerodynamic forces were measured with a new type of device. The wind resistance of each model was tested by the windward angles of 4 ~ (?), 0 ° and + 4 ~ (?). The non-linear characteristics of wind and amplitude and the second-order harmonic locking phenomenon were also probed. Finally, the stability of the end of Guang-Guang Bridge is introduced. Wind tunnel tests under laminar flow conditions show adequate wind stability with the addition of special flaps on the railing. Finally, turbulence effects were examined not only by wind tunnel tests but also by field observations of real bridge responses.