箱型钢管混凝土劲性骨架柱抗震性能与抗震设计简化算法的研究

Box sectional CFST-RC column has been adopted in the high-pier construction in mountainous areas due to its advantages of simple structure, material saving, convenient construction, and good seismic performance, which is a new type of composite structure with huge development potential. However, the related research on seismic performance of box sectional CFST-RC column is insufficient. Therefore, to investigate the seismic performance of box sectional CFST-RC column under static cyclic loading and strong seismic excitations, quasi-static cyclic test, pseudo-dynamic test, and numerical simulation method will be adopted in this research. First, the influences of the distance between CFST limbs, the strength coefficient of CFST, wall-thickness of box section, and the axial load ratio on the ductility and strength of the specimen are clarified on the basis of experimental study and numerical mechanism analysis; Second, the reasonable structural configuration and simplified calculation method of horizontal strength are presented; Third, the effect of the characteristic of ground motion on the capacity of energy dissipation, stiffness and ductility of this kind of compression-bending member is studied and the practical hysteretic model is proposed; Finally, an improved seismic design method for box sectional CFST-RC column is proposed. The above work can be used to supply scientific evidence for helping this innovative composite structure to be applied in actual projects and relative criterion revision.

箱型钢管混凝土劲性骨架柱具有构造简单、节约材料、施工方便、抗震性能好等优点，可应用于山区桥梁高墩建设中，是一种具有发展潜力、值得深入研究的新型组合结构。但目前针对这种新型结构抗震性能的相关研究尚处于起步阶段。因此，本项目拟采用拟静力试验、拟动力试验和数值模拟法，对该类构件在低周反复荷载和强震荷载作用下的抗震性能开展应用基础研究。基于试验研究和有限元数值机理分析，明晰钢管混凝土柱肢间距、钢管混凝土强度系数、箱型截面壁厚、轴压比等参数对构件延性和水平极限承载力的影响规律；建议此类构件的合理构造措施和水平承载力的简化算法；研究地震波特性对该类压弯构件的耗能能力、刚度和延性的影响规律，确定该类构件的实用恢复力模型；建议该类新型构件的抗震设计方法。以上工作可为该类新型构件在实际工程中的应用提供科学依据，为推动我国结合结构的推广应用与科技进步作出贡献。

箱型钢管混凝土劲性骨架柱（简称“劲性骨架柱”）是将钢管混凝土格构柱（简称“格构柱”）作为劲性骨架埋入空心薄壁钢筋混凝土中的一种新型组合结构，在我国山区高墩建设中具有广阔的应用前景和发展潜力。但目前此类结构的相关抗震性能研究尚处于起步阶段。因此，本项目采用拟静力试验（7根格构柱和5根劲性骨架柱）、拟动力试验（1根格构柱和2根劲性骨架柱）和数值模拟法，对该类构件在低周反复荷载和强震荷载作用下的抗震性能开展应用基础研究。基于试验研究和有限元数值机理分析，首先，明确了格构柱和劲性骨架柱的破坏机理，格构柱的破坏模式主要表现为柱肢底部钢管局部屈曲和缀管与柱肢连接处受剪破坏，劲性骨架柱的破坏模式主要表现为柱肢底部钢管局部屈曲引起的外包混凝土竖向裂缝、纵桥向腹板上的剪切斜裂缝、横桥向腹板底部的水平向裂缝；其次，明晰钢管混凝土柱肢间距、钢管混凝土强度系数、箱型截面壁厚、轴压比等参数对格构柱和劲性骨架柱延性和水平极限承载力的影响规律，并据此建议此类构件的合理构造措施和水平承载力的简化算法；同时，研究地震动特性对该类压弯构件的耗能能力、刚度和延性的影响规律，确定该类构件的实用恢复力模型，建议该类新型构件的抗震设计方法。以上工作可为劲性骨架柱此类新型构件在实际工程中的应用提供科学依据，为推动我国结合结构的推广应用与科技进步做出贡献。