近场脉冲型地震作用下附加支撑双柱式摇摆桥墩的抗震性能研究

STUDY ON SEISMIC PERFORMANCE OF DOUBLE-COLUMN ROCKING BENTS WITH ADDITIONAL BRACES UNDER NEAR-FIELD PULSE GROUND MOTIONS

  • 摘要: 为了解决摇摆桥墩承载力和耗能能力不足的问题,该文提出一种附加人字形支撑的双柱式摇摆桥墩结构,支撑为纯耗能支撑或自复位耗能支撑,支撑通过连接装置安装在双柱式摇摆桥墩的盖梁和承台之间。为了研究新型附加人字形支撑双柱式摇摆桥墩的抗震性能,对其进行拟静力分析,将双柱式现浇桥墩和双柱式纯摇摆桥墩作为对比模型,研究附加纯耗能支撑和自复位耗能支撑双柱式摇摆桥墩的滞回性能;分别对这四种桥墩结构进行动力时程分析,探究这四种桥墩在近场对称脉冲、近场非对称脉冲和远场无脉冲地震动作用下的动力响应。研究结果表明:附加支撑的双柱式摇摆桥墩中的墩柱仍具有摇摆机制,可有效避免墩身出现塑性铰发生严重的损伤破坏,同时附加的支撑可以显著提高桥墩的承载能力和耗能能力,有效降低桥墩结构的位移响应,特别是自复位耗能支撑还可额外为桥墩提供自恢复力,有效提高结构的抗震性能。

     

    Abstract: To solve the issues of insufficient bearing and energy dissipation capacities of rocking bents, a double-column rocking bent structure with braces placed in chevron arrangement is developed in this study. The braces are pure energy dissipation ones or self-centering energy dissipation ones, installed between the cap beam and the foundation of the double-column rocking bent by connecting devices. To study the seismic performance of the double-column rocking bent structure with braces developed, its quasi-static analysis is carried out firstly. Taking the double-column cast-in-situ bent and the double-column rocking bent as the comparative model, the hysteretic behavior of the double-column rocking bent with additional braces are investigated; The dynamic time history analysis of these bents is carried out to explore the dynamic responses of the structures due to the near-field symmetrical pulse, to near-field asymmetrical pulse and to far-field non pulse ground motions. These results show that: the double-column rocking bent with additional braces still behaviors the rocking mechanism, which can effectively avoid the serious damage to the plastic hinge of column; at the same time, the additional braces can significantly improve the bearing capacity and energy dissipation capacity of the bent and, reduce the displacement response of the bent; especially, the self-centering energy dissipation braces can also provide additional self-centering force for the bent, which can effectively improve the seismic performance of the bent.

     

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