矩形钢管高强混凝土框架抗震性能分析

为研究地震作用下矩形钢管高强混凝土框架的破坏机理和抗震性能，进行了单跨两层矩形钢管高强混凝土框架低周反复荷载试验和有限元分析. 考察结构试件在试验过程中塑性铰出现的位置、顺序及塑性发展程度，研究其破坏机制和破坏模式. 研究结构滞回曲线与骨架曲线，分析其承载能力、变形能力、耗能能力以及强度和刚度退化情况. 在此基础上，采用有限元软件Perform-3D对矩形钢管高强混凝土框架试件进行参数分析，研究了轴压比、钢材屈服强度及静力弹塑性分析水平侧向力加载模式等对结构抗震性能影响. 结果表明:矩形钢管高强混凝土框架试件呈梁铰破坏形态，并具有承载能力高、变形能力和耗能能力强的特点. 试件平均峰值荷载较屈服荷载提高了1.68倍；顶层和底层最大层间位移角分别为1/30和1/27，分别超过了规范规定限值的66.7%和85.2%. 延性系数分别超出了规定限值的58.5%和60.0%；轴压比对结构抗震性能影响显著. 当轴压比大于0.6时，结构承载能力与变形能力明显降低；水平侧向力加载模式对结构承载能力影响大. 均匀加载模式下结构承载能力最大，顶点加载模式下最小，倒三角形加载模式居于二者之间. 研究成果可为矩形钢管高强混凝土框架结构抗震设计提供参考. 

Seismic Behavior of Rectangular High-Strength Concrete-Filled Steel Tube Frame Structure

In order to study the failure mechanism and seismic performance of rectangular high-strength concrete-filled steel tube (RHCFT) frames, the cyclic loading test as well as the finite element (FE) analysis was conducted on a single-span and two-story RHCFT frame. During the test, the formation process of plastic hinge in the specimen including the location, sequence and degree of plastic development of the plastic hinge was investigated to study the failure mechanism, and thus the failure mode of the specimen. According to the hysteretic curves and backbone curves from the experiment, the seismic performance of the RHCFT frame, including the bearing capacity, the deformation ability, the energy dissipation capacity as well as the strength and stiffness degradation, was examined. On this basis, the FE analysis model of the RHCFT frame specimen was created using Perform-3D. The effects of the axial compression ratio, the steel yield strength, and the lateral load pattern on the seismic performance of the structure were examined. The results show the RHCFT frame demonstrates a strong column and weak beam failure mode, and has the characteristics of high bearing capacity, deformation capacity, and energy dissipation capacity. The average peak load of the specimen is 1.68 times higher than the yield load. The maximum inter-story drift ratios of the top and bottom stories are 1/30 and 1/27, respectively, which exceed 66.7% and 85.2% of the limit specified in the specification. The ductility coefficients exceed the prescribed limit by 58.5% and 60.0% respectively. The axial compression ratio has a significant effect on the seismic performance of the structure. When the axial pressure ratio is greater than 0.6, the bearing capacity and deformation capacity of the structure decrease drastically. The lateral load pattern have a great influence on the bearing capacity of the structure. The load capacity of the structure is the largest under uniform loading pattern, the smallest under vertex loading mode, and the inverted triangle loading pattern is between them. The research results can provide reference for the seismic design of rectangular high-strength concrete-filled steel tubular frame structures.