反向芬克式桁架人行桥抗风性能研究

Study on Wind Resistance Performance of Inverted Fink Truss Footbridge

反向芬克式桁架结构作为近年来新兴的桥梁结构形式,具有简洁和造型美观等优点,已在国外多座人行桥中得到应用。鉴于人行桥结构轻柔等原因,该类型人行桥的风效应问题成为设计关注的重点之一,但国内相关研究较少。现依托主跨150 m的反向芬克式行架人行桥工程实际,开展了系统的抗风性能试验研究。结果表明:参照我国《公路桥梁抗风设计规范(JTG/T3360-01-2018)》,该桥的颤振稳定性、静风稳定性等都满足要求;在均匀流场的0°和+3°风攻角下,涡激共振峰值振幅超过规范允许值,在5%紊流度、将结构阻尼比从0.3%增加到1%之后,涡激共振得到不同程度的抑制,并满足规范要求;进一步分析表明,增加结构阻尼比,将是更为有效的抑制该桥主梁涡激共振的措施。

As a new type of bridge structure in recent years,the Inverted Fink Truss has the advantages of simplicity and beautiful shape.It has been applied in many footbridges abroad.In view of the soft structure of the footbridge,the wind effect of this type of footbridge has become one of the focuses in design,but the domestic research is scarce.Based on the engineering practice of a Inverted Fink Truss with main span of 150 m,this paper carried out systematic wind resistance test research.The results show that:referring to Wind-resistance Design Specification Highway Bridge(JTG/T3360-01-2018),the vibration stability and aerostatic stability of the bridge meet the requirements.At the wind attack angles of 0° and+3° in the uniform flow field,the peak amplitude of vortex-excited resonance exceeds the allowable value of the specification.After 5% turbulence intensity and increasing the structural damping ratio from 0.3% to 1%,the vortex-excited resonance is suppressed to varying degrees,and meets the specification requirements;further analysis shows that increasing structural damping ratio will be effective to suppress the vortex-excited resonance.