钢桁架人行桥行人风环境及抗风性能研究

A study on pedestrian level wind environment and wind-resistance performances of a steel truss footbridge

以某在建钢桁架人行桥为工程依托,采用计算流体动力学方法(CFD)对非对称截面钢桁架人行桥主梁三分力系数、桥面行人风环境进行了数值模拟;采用风洞试验方法对非对称截面钢桁架主梁进行了涡振性能和颤振性能、三分力系数风洞试验研究。结果表明:桁架内文化墙对钢桁架下侧桥面行人风环境影响较大,适当增加文化墙与上、下弦杆之间间隙可有效改善钢桁架下侧桥面行人风环境;非对称钢桁架曲线人行桥风从左右两侧吹时三分力系数存在明显的差异;非对称钢桁架曲线人行桥存在明显涡激共振现象,采用调谐质量阻尼器(TMD)可有效减小钢桁架人行桥涡振响应幅值。

Based on a steel truss footbridge under construction,numerical simulations of aerodynamic coefficients and pedestrian level wind environment on bridge deck of the steel truss section were conducted firstly using computational fluid dynamics(CFD).Finally,the aerodynamic coefficients,vortex-induced vibrations,and flutter instability of the steel truss footbridge were investigated with wind tunnel tests.The research results show that the cultural wall inside the steel truss has great effects on the pedestrian level wind environment on the bottom bridge deck.Appropriate increase of the gaps between the cultural wall and the bottom and top chords of the truss can effectively improve the pedestrian level wind environment on the bottom bridge deck.The aerodynamic coefficients of the steel truss with asymmetry section under the wind blows from left side are obviously different from that of the bridge deck under the wind blows from the right side.There is obvious vortex-excited resonance of the steel truss footbridge with asymmetry section.The amplitudes of the vortex-excited resonance of the steel truss footbridge can be effectively reduced with tuned mass dampers(TMD).