基于法兰连接的离心式中空RC节段桥墩抗震性能试验研究

    Seismic Behavior Tests of Centrifugal Circular Hollow Segmental RC Column With Flange Connection

    • 摘要: 为了解决法兰连接在混凝土墩柱中应用时面临的连接方式难实现、受力机理不明确及抗震性能不清晰等问题, 提出一种基于法兰连接的离心式中空钢筋混凝土(reinforced concrete, RC)节段桥墩柱-柱节点拼装方案, 从而进一步完善桥梁下部结构预制装配技术。依托于监利至江陵高速公路洪湖一号特大桥工程, 设计制作了一个高度为5.6 m的1∶1足尺模型墩柱试件, 并开展了拟静力试验和数值模拟分析以研究其抗震性能和破坏模式。基于屈服线理论和T形连接节点模型, 分析了法兰端板和螺栓受力机理, 建立了法兰连接节点的抗弯能力计算模型。结果表明, 将法兰节点设置在最不利受力位置即墩柱底部塑性铰区时, 基于法兰连接的离心式中空RC节段桥墩在弹性阶段的力学性能仍接近传统现浇墩柱, 且满足低烈度区实际工程中的抗震设计要求。但桥墩屈服后在连接节点处发生破坏, 说明其耗能能力具有一定的局限性, 因此对于中高烈度区应用需开展进一步的研究。所建立的节点受力模型合理地解释了节点破坏的原因, 并据此推出了一套该法兰连接节点端板厚度和钢筋直径的设计流程, 为未来在中高烈度区应用提供设计建议。

       

      Abstract: To solve the problems faced by the flange connection in the application of concrete piers, such as difficult connection implementation, indistinct force mechanism, and unclear seismic performance, this paper proposes a new flange connection-based centrifugal circular hollow segmental RC column-column node assembly scheme. Thus, the prefabricated assembly technology of the bridge substructure can be further improved. Based on the Jianli-Jiangling Expressway Honghu No. 1 Special Bridge project, a 5.6 m height 1∶1 full-scale model was designed and fabricated. Its seismic performance and failure modes were studied by conducting the quasi-static load test and numerical simulation analysis. Based on the yield line theory and T-node model, the force mechanism of plates and bolts in flange connection nodes was analyzed, and the calculation model of the bending resistance of flange connection nodes was established. Results show that when the flange node is set at the most unfavorable bearing position, which is the plastic hinge area at the bottom of the pier, the mechanical properties of flange-connected precast piers are close to those of conventional cast-in-place piers in the elastic phase and meet the seismic design requirements of low-intensity zones in the actual projects. However, the damage occurs at the flange node after the bridge pier yielded, which indicates that its energy dissipation capacity has some limitations. Therefore, further research is needed for the application in medium and high-intensity zones. The proposed node force model reasonably explains the cause of the damage. Accordingly, a design method for plate thickness and reinforcement diameter applicable to this flange connection node is proposed to provide design recommendations for future applications in medium and high-intensity zones.

       

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