悬挑环形廊桥的气动弹性模型试验

Aeroelastic model study of cantilever skywalk bridge

针对目前世界上最大悬挑环形玻璃廊桥的抗风设计,建立针对该类桥梁风效应的全气动弹性模型研究方法,以解决基于片条假定的经典桥梁风振理论无法应用于复杂风场下人行桥梁的三维风响应问题.该方法包括根据相似原理选择模型设计参数、针对复杂原型结构系统进行模型的工艺设计以及在风洞中模拟山地地貌造成的大攻角效应.这一方法还包括一种面向设计的计算方法,能够依据荷载效应求算静力等效风荷载分布.结果表明,提出的全气动弹性模型的试验与分析方法对解决复杂风场下复杂桥梁结构的三维风响应问题具有普遍适用性,不但能够提供满足这类结构抗风设计的气动稳定性、设计风荷载与风振加速度等各项参数,而且能够揭示这类结构风效应对结构参数的敏感度,有助于结构的优化设计.

Conventional theory on wind-induced bridge responses was based on strip assumption which is not applicable to three-dimensional pedestrian bridges in complex wind conditions.A method of using full aeroelastic model was developed for the wind-resistant design of the world longest cantilever skywalk bridge in order to solve the problem.Details of the method include the selection of model design parameters to meet similarity requirements,technological scheme of the model for complex threedimensional prototype structural systems,and wind tunnel simulation of large angle of attack caused by hilly effects.A design-orientated approach was developed for equivalent static wind load distributions based on load effects.The proposed method was verified to have general applicability to deal with wind effects on three-dimensional bridge structures in complex wind environment.Not only the aerodynamic stability,the design wind loads and the accelerations for wind-resistant design can be reliably estimated,the sensitivity of wind effects on structural properties,which is important for structural optimization design,can also be readily examined with the proposed method.