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将处于自然风中一前一后并列布置的大跨度桥梁相互之间可能存在的不确定相互气动干扰处理成随机气动干扰,并归入到紊流风随机激励中,采用基于模态参数识别的随机子空间识别方法,开发了桥梁断面颤振导数识别的专用程序,并以具有理论解的Theodorsen平板为例,通过系统响应数值仿真和颤振导数识别,验证了该方法的可靠性。针对实际大跨度桥梁,设计了并列节段模型试验悬挂系统,开展了紊流风和随机气动干扰效应下的并列大跨度桥梁节段模型风洞试验,将迎风、背风侧桥梁断面的颤振导数结果与均匀流、紊流风中单个桥梁断面颤振导数值进行了对比。结果表明:背风侧桥梁对迎风侧桥梁的颤振导数影响很小,而迎风侧桥梁对背风侧桥梁的颤振导数有较大影响;该研究方法为存在这种随机气动干扰的并列大跨度桥梁颤振导数识别提供了一个较为合理的途径。
The uncertainties of mutual aerodynamic interference between the long-span bridges arranged side by side in the natural wind can be treated as random aerodynamic disturbances, which are classified into the random excitation of turbulent winds. The stochastic excitation based on modal parameters identification The special program of bridge cross-section flutter derivative identification was developed. Based on the Theodorsen plate with theoretical solution, the reliability of the method was verified through numerical simulation of system response and flutter derivative identification. Aiming at the actual long-span bridges, a parallel-section model test suspension system was designed. The wind tunnel test of parallel long-span bridge segment model with turbulent wind and random aerodynamic interference was carried out. The flutter derivative results Compared with the flutter derivative of single bridge cross section in uniform flow and turbulent flow. The results show that the leeward side bridges have little effect on the flutter derivatives of the windward side bridges, while the bridge on the leeward side has a great influence on the flutter derivatives of the leeward side bridges. The proposed method is the parallel long-span bridge with such random aerodynamic disturbances Flutter derivative identification provides a more reasonable way.