考虑行波效应的刚架系杆拱桥减隔震分析

Analysis of Seismic Isolation for Frame Tied Bridge under the Effect of Traveling Wave

研究目的:以某跨度(24+160+24)m刚架系杆拱连续箱梁组合桥为工程背景,采用大质量法(LMM)实现多点激励以考虑行波效应影响,对比分析减隔震措施采用前后结构的地震响应,并对弹性连接装置、粘滞阻尼器两种减震装置进行合理参数选取,为拱桥合理减隔震措施的选择提供依据。研究结论:(1)考虑行波效应后,减震装置参数对减震效果有较大影响,对比弹性连接装置和粘滞阻尼器(经合理参数选取)的减震效果可知,对于拱肋轴力减震效果,两种装置差别不大,对于拱肋弯矩减震效果,设置弹性连接装置更佳;(2)隔震体系的采用,减震装置全桥对称设置可以有效缓解行波效应的不利影响,使拱肋受力趋于均匀;(3)单纯采用隔震体系虽可有效降低结构的频率,但却引起结构较大的位移幅值,减震装置的施加可以有效降低结构的位移幅值;(4)该研究成果可应用于指导拱桥抗震设计。

Research purposes： Taking a frame tied bridge with continuous box girder whose span arrangement is （24 ＋ 160 ＋24） m as an engineering background, this paperadopts multi -point excitation realized by large mass method to consider the effect of traveling wave. And the responses of structures with different systems were analyzed comparatively, and parameters of elastic link device and viscous damper were selected reasonably to provide the basis for the reasonable selection of seismic isolation measures of arch bridge. Research conclusions：（ 1 ） Parameters of damping device have a great impact on damping effect when the effect of traveling wave is considered. The comparison results of damping effect indicate that elastic link device and viscous damper have the same damping effect to axial force of ribs, but choosing elastic link device is better when involving decreasing bending moment of ribs. （2） The application of isolation system and the symmetry of damping device＇s set can make the distribution of internal force of ribs evenly, which can relieve the adverse effect of traveling wave. （3） Only using isolation system can reduce structure frequency effectively, but will lead to large displacement amplitude. The installation of damping device can reduce displacement amplitude significantly. （4） The research results can be used in guiding for seismic design of arch bridge.