墙板内置无黏结支撑钢框架滞回性能数值模拟

为深入研究梁柱节点形式、加强方式等对墙板内置无黏结支撑钢框架结构滞回性能的影响,对3个结构试验进行了数值模拟。基于墙板内置支撑构件滞回性能的试验研究,确定出了体现往复作用下支撑钢材强化特性的参数取值.总体上,数值分析得到的结构滞回曲线、构件的屈服或局部屈曲机制等均与试验结果较一致,试验和模拟中支撑分别在层间侧移角约1/463~1/350和1/416~1/305范围内发生屈服,框架在1/50层间侧移角之前塑性发展较少,结构的延性和耗能能力良好,实现了结构1/50侧移角内主要利用支撑屈服耗能的设计意图.1/30侧移角内,框架承载力出现退化前,梁柱刚接结构的骨架曲线呈三折线,可分别由支撑和框架的两折线骨架曲线叠加得到;梁柱铰接的结构在破坏前骨架曲线呈双折线,框架塑性发展甚少.梁端补贴钢板加强后梁端塑性区外移,确保了梁柱刚接节点的强度和框架稳定耗能.人字形支撑铰接框架中一根支撑较早局部破坏后被撑梁大幅弯曲屈服,整个结构的抗侧承载力未出现退化.给出了采用梁、杆单元简化模拟墙板内置支撑钢框架结构滞回性能的方法.

Numerical simulation on hysteretic behavior of steel frame with unbonded steel plate brace encased in panel

Numerical simulations were performed to further investigate the effects of beam-to-column connections, reinforced ways, etc. on the hysteretic behavior of three tested steel frames with unbonded steel plate brace encased in panel (referred to as panel BRB), which is termed as steel frame with panel BRB (panel BRBF) hereafter. The values of the parameters used to reflect the hardening behavior of panel BRBs were determined based on cyclic tests of panel BRBs. In general, hysteretic curves of panel BRBFs and mechanism on yielding or buckling of steel members acquired from simulations agreed with those from tests. Yielding of panel BRBs occurred at inter-story drifts of 1/463~1/350 in tests and 1/416~1/305 in simulations, and plastic deformations of steel frames were not obvious prior to the drift of 1/50. Ductility and energy dissipation capacity of panel BRBFs were good and the design aim that yielding of panel BRBFs is mainly concentrated on panel BRBs was realized. Within the drift of 1/30 and prior to deterioration of load carrying capacity of steel frames, the panel BRBFs with moment-resisting beam-to-column connections and the panel BRBF with non-moment-resisting beam-to-column connections, in which steel frames nearly remained elastic, showed trilinear and bilinear skeleton curves, respectively. The trilinear curve of each panel BRBF can be acquired by putting the bilinear skeleton curves of both panel BRB and steel frame together. The reinforced ways of adding steel plates at the ends of steel beams near moment-resisting beam-to-column connections let yielding of beams occur far away from the beam-to-column connections and ensured both enough strength of the connections and stable energy dissipation capacity of steel frames. The beam in the panel BRBF with non-moment-resisting beam-to-column connections had large flexural yielding when one brace in a chevron panel BRB failed locally, and the overall lateral resistance of structure was not deteriorated. Besides, simplified methods by employing beam and truss elements to simulate hysteretic behavior of panel BRBFs were proposed.