新型SCEB力学性能及其在双柱式桥梁结构中的应用

Mechanical Performance of New Type of Self-centering Energy Dissipation Brace and Its Application in Double-column Bridge Structures

基于结构"保险丝"概念和减小残余位移的目的,提出采用自复位耗能支撑(SCEB)应用于双柱式桥梁结构的设计理念。首先提出一种新型SCEB-自复位防屈曲支撑,阐明其工作机理并通过试验验证了其力学性能;然后基于新型SCEB的力学性能,建立附加SCEB双柱式桥墩结构的恢复力模型,并给出双柱式桥墩结构中新型SCEB的设计方法,通过合理设计SCEB使其先于桥墩屈服并耗能,可减小主体结构墩身的地震损伤,并且能够有效控制桥梁结构震后的残余位移;最后基于OpenSees软件平台,验证SCEB应用于双柱式桥梁结构中的可行性和有效性,并对附加新型SCEB的双柱式桥梁结构进行抗震性能分析。新型SCEB试验结果验证了合理的设计能够实现新型支撑具有稳定的耗能能力和良好的自复位功能,其力-位移滞回曲线呈明显的旗帜形特征;数值模拟结果不仅验证了附有"保险丝"构件的新型耗能桥梁结构的抗震性能优于传统横系梁桥梁结构,还验证了SCEB作为"保险丝"附加在桥梁结构中的有效性;附加新型SCEB的双柱式桥梁结构与附加传统BRB双柱式桥梁结构相比,在提高桥梁结构横向刚度的同时,对桥墩主体结构具有更好的保护作用和耗能能力,特别是能够减小甚至消除桥梁结构的残余位移。

Based on the concept of structural fuses and the target of reducing residual displacement, the design concept of self-centering energy dissipation brace （SCEB） applied in the structural fuse for double-column bridge structure was proposed. Firstly, a novel SCEB-self-centering buckling restrained brace was proposed. The working mechanism was clarified and the mechanical behavior of the SCEB was experimentally verified. The restoring force model of double-column bridge piers with SCEB was then established based on the mechanical performance of the SECB, and the design method of the SCEB for double-column bridge pier was proposed. The damage of the column could be reduced and the residual displacement of the structure could be effectively controlled, with the reasonable design of the SCEB for yielding and dissipating energy before the column. Numerical analyses on seismic performance of the pier with the SCEB were carried out by OpenSees FE platform to assess the viability and the availability. The results show that the proposed SCEB exhibits good self-centering abilities and moderate energy dissipation capability, and force-displacement hysteretic curves present the flag-shaped characteristic. Numerical simulations manifest that the seismic performance and energy dissipation capacity of bridge with the fuse element are better than those of the cross link beam structure, and SCEB used in double-column piers is effective. In particular, the SCEB, compared with BRB, can enhance the lateral stiffness, the protective action and energy dissipation capacity of bridge columns to mitigate the seismic damage of columns. The residual displacement of columns can be effectively reduced and eliminated by SCEB.