新型内嵌耗能壳板箱形钢桥墩抗震性能与设计方法研究

Due to heavy self-weight and poor ductility of the traditional reinforced concrete bridge piers, the traditional piers tend to damage under severely seismic action and the repairing of reinforced concrete bridge piers is complex. A new type of steel box bridge pier embedded dissipative shell plates is developed. The mechanical behavior and seismic design theory of the new type bridge pier will be systematically investigated based on seismic-response control theory. The pseudo-static experiment under three-dimensional loading, numerical simulation and theoretical analysis of the new type bridge pier will be conducted. The buckling mechanism, dissipative mechanism and the interactive buckling relationship between embedded dissipative shell plates and pier plates of the new type bridge pier will be discussed. The characteristics of hysteresis curves of the new type bridge pier will be obtained, and the restoring force model of the steel bridge pier will be established. The influence rules of three-dimensional seismic coupling action, axial compression ratio, slenderness ratio, height-to-width ratio of section, width-to-thickness ratio of plate and retrofitting measure of embedded dissipative shell plates on the seismic behavior of the new type bridge pier will be analyzed. Based on experimental study and theoretical analysis, the simplified formulas of stiffness, deformation and load-bearing capacity of the new type of steel box bridge pier embedded dissipative shell plates will be proposed. The allowable values of seismic deformation of steel bridge piers on different performance levels will be suggested. The study results will provide scientific basis on performance-based seismic design theory and application in actual structures of the new type of steel box bridge pier embedded dissipative shell plates.

传统的钢筋混凝土桥墩由于自重大且延性差，在较强地震作用下易损坏，且难以修复。本课题提出一种新型内嵌耗能壳板箱形钢桥墩，并基于损伤控制理论对其力学行为和抗震设计理论进行系统研究。通过新型桥墩的三向拟静力试验、数值模拟和理论分析，研究内嵌耗能壳板箱形钢桥墩屈曲机理、耗能机理以及内嵌壳板与桥墩壁板相关屈曲关系，获得新型桥墩的滞回特性曲线，建立钢桥墩的恢复力模型。同时分析三向地震耦合作用、轴压比、长细比、截面高宽比、壁板宽厚比、内嵌壳板等构造对新型桥墩抗震性能的影响规律。在试验研究与理论分析的基础上，提出新型内嵌耗能壳板箱形钢桥墩刚度、变形及其承载能力的简化计算公式，并提出不同性能水准下钢桥墩的抗震变形容许值。研究成果为新型内嵌耗能壳板箱形钢桥墩基于性能的抗震设计理论及工程应用提供科学依据。

传统的钢筋混凝土桥墩由于自重大且延性差，在较强地震作用下易损坏，且难以修复。基于损伤控制理论，研发出新型内嵌耗能壳板的箱形钢桥墩，可提升城市抗震救灾能力，并能显著降低施工对城市生态环境和交通的不利影响。.为研究内嵌耗能壳板新型箱形钢桥墩的抗震性能，开展了新型箱形钢桥墩的拟静力试验、数值模拟和理论分析工作。分析了三向地震耦合作用、轴压比、长细比、截面高宽比、壁板宽厚比、内嵌壳板等构造对新型桥墩抗震性能的影响规律。同时探讨了新型箱形钢桥墩根部耗能区的轴压屈曲机理和变形性能，并研究了箱形偏心压弯钢柱的抗震性能。在试验研究和理论分析的基础上，提出了新型箱形钢桥墩的抗震设计建议公式。研究得出以下主要结论：.（1）设置内嵌壳板后，新型箱形钢桥墩的承载能力和极限位移都有增大；骨架曲线下降段也变平缓，箱形钢桥墩的变形能力增强，延性更好。.（2）轴压比和内嵌壳板的横向加劲肋间距对新型箱形钢桥墩抗震性能的影响较为显著。轴压比和内嵌壳板的横向加劲肋间距越小，试件的承载能力和极限位移越大，骨架曲线下降段越平缓，箱形钢桥墩的变形能力和延性越好。.（3）设置壁板纵肋和增大内嵌壳板强度对箱形钢桥墩的承载能力和延性性能的影响相对较小。.（4）考虑三向地震耦合作用后，试件滞回曲线包围的面积将减小，试件耗能能力将降低。三向地震耦合作用对试件的变形能力影响较大，而对试件强度的影响相对较小。.（5）内嵌壳板可有效提高箱形钢桥墩的承载能力和变形能力，内嵌壳板厚度、壁板宽厚比、轴压比和长细比对新型钢桥墩抗震性能的影响较为显著。.（6）为便于新型箱形钢桥墩的抗震设计，在理论分析和数值模拟的基础上，建立了根部内嵌壳板耗能区的最小高度、轴力与弯矩相关稳定承载力及位移延性系数的计算公式。.通过本项目的研究，获得了内嵌耗能壳板箱形钢桥墩的屈曲传力机理、抗震性能和设计方法，为新型箱形钢桥墩的工程应用提供科学依据。