设置阻尼支撑对钢管混凝土拱桥纵桥向减震效果的分析

Analysis on vibration reduction of CFST arch bridge with damping braces in span direction

以主跨为85 m的无推力靠背式下承拱桥为研究对象,旨在供大跨度钢管混凝土拱桥采用消能减震技术进行抗震设计提供参考.在分析动力特性的基础上进行不同强度纵桥向地震荷载作用下的地震反应分析;然后采用消能减震技术在不同部位设置阻尼支撑,并进行相应的地震反应时程分析,确定阻尼支撑的合理设置形式,比较阻尼支撑设置前后的位移、加速度响应时程,探讨阻尼支撑对钢管混凝土拱桥减震效果.研究成果表明,在钢管混凝土拱桥的拱圈与桥面主梁间设置与桥面系成约45°的阻尼支撑有较好的减震效果,能降低位移响应峰值约30%,同时能够降低结构的内力(尤其是弯矩).故可通过消能技术使钢管混凝土拱桥在地震荷载作用下有效控制位移和内力,并使内力分布均匀化,降低拱圈失稳发生的可能性.

A 85 m coupler-form non-thrust between supports concrete-filled steel tube （CFST） arch bridge was se lected as study object with energy dissipation technique in large span CFST arch bridges. The dynamic analysis and response subjected by different intensity seismic loads parts, and the time history analyses were conducted. were carried out. The damping braces were set in different The rational setting of damping braces was discussed, the effectiveness of reducing vibration of CFST arch bridge was investigated based on the comparisons of the displacement and acceleration responses before or after setting damping braces. Finally, the results show there is a better vibration reduction by setting damping braces between arch and bridge deck beam, the braces in about 45° with the deck, and the peak displacement can reduce about by 30%. Simultaneously, the internal forces of structure can be reduced, especially for girder bend moment. So it＇s a new way to reduce the response of earthquake, and also an effective method to lower the probability of losing arch stability.