基于OpenSees的方钢管混凝土柱-不等高钢梁框架节点抗震性能分析

为研究方钢管混凝土柱-不等高钢梁节点的抗震性能,基于4个方钢管混凝土柱-不等高钢梁节点的低周往复加载试验,利用Open Sees开放平台,建立了梁柱节点数值模型。为考虑钢管混凝土-钢梁的实际受力性能,梁柱节点区域采用梁柱纤维单元、非线性弹簧以及剪切区组合建立。通过数值模拟分析了钢管强度等级、梁高比、试验轴压比、核心混凝土强度对不等高钢梁框架节点抗震性能的影响。结果表明:钢管强度等级的增大有利于提高节点的延性和极限承载力,且Q390性价比最高,极限承载力增幅最大为11. 5%;随着左右两侧梁高比的增大,节点承载力上升显著,当梁高比为0. 8时,承载力增幅最大为17. 75%;试验轴压比会导致节点承载力下降,且大于0. 5时,下降幅度十分明显,在设计中应当重视;混凝土强度等级的提升对节点承载力及刚度的影响较小。

Seismic Performance Analysis on Steel Unequal-depth-beams to Concrete-Filled Square Steel Tubular Column Joints Based on OpenSees

In order to analyze the seismic performance of joints with concrete-filled square steel tubular column and unequal depth steel beams, a numerical model of joints was established on OpenSees open platform based on the low-cycle reciprocating loading tests of 4 joints concrete-filled square steel tubular column and unequal depth depth steel beams. The joints was comprised of advanced fibre beam-column elements, non-linear springs and shear panel for considering the true mechanical properties. The effect of steel tubular strength grade, the depth ratio of beam, the experimental axial compression ratio and concrete strength grade on seismic performance of the joints with unequal depth were analyzed by numerical simulation. The results show that the increase of the strength of steel tubular is beneficial to improve the ductility and ultimate bearing capacity of the joints, and the Q390 is the most cost-effective to increase the bearing capacity by 11.5%. The influence of the depth ratio of beams on the bearing capacity of the joints is significant. When the depth ratio of beams is 0.8, the bearing capacity increases by 17.75%. With the increase of the experimental axial compression ratio, the bearing capacity of the joints decreases. And when the experimental axial compression ratio is higher than 0.5, the decrease is obvious, which should be paid attention to in the design. The increase of concrete strength grade has little influence on the bearing capacity and stiffness of the joints.