蜂窝式钢框架结构合理扩高比限值分析

Reasonable Expansion Ratio Limit Analysis of Cellular Steel Frame Structure

目的研究蜂窝式钢框架结构的受力特点、破坏模式以及抗震性能.方法对单层单跨蜂窝式钢框架结构进行水平低周反复加载试验,控制蜂窝梁扩高比K=1.5,对蜂窝式钢框架结构的受力特点、破坏模式以及抗震性能等因素进行分析.在此基础之上,利用有限元分析软件对足尺蜂窝式钢框架结构进行模拟分析,研究了三层单跨六边形孔和圆形孔蜂窝式钢框架结构的破坏模式、滞回曲线、骨架曲线、延性和耗能能力.结果蜂窝式钢框架结构基本都发生梁铰破坏机制,但是腹板削弱造成孔洞位置处的抗剪承载力降低,影响了塑性铰的转动能力,因此其耗能能力和延性低于实腹钢框架,但是延性仍处于较高的水平.通过分析不同扩高比下六边形孔和圆形孔蜂窝式钢框架结构延性系数,拟合出扩高比与延性系数的关系曲线.结论孔洞腹板的削弱程度决定其延性水平,通过拟合出的扩高比与延性系数的关系曲线,利用提出的抗震等级与延性的关系,提出两种孔型蜂窝式钢框架结构在不同抗震等级下的扩高比限值,为蜂窝式钢框架结构抗震设计提供参考.

In order to study the mechanical characteristics, failure modes and seismic performance of cellular steel frame, horizontal low cyclic loading test of the single-story and single-span cellular steel frame structure was performed. Mechanical characteristics, failure modes, seismic performance, and other factors were analyzed, when the castellated bear expansion ratio is 1.5. Based on the test, with usage of the finite element software to establish simulation analysis of full-scale cellular steel frame, the failure modes, hysteretic curve, skeleton curve, ductility and energy dissipation capacity of three-story one-bay hexagonal holes and round holes cellular steel frame structure are studied. Cellular steel frame basically has beam hinge damage mechanism. However, shear beating capacity reduction in the hole position is caused by steal beam reduction and it affects rotation caparity of the plastic hinge. So its the energy dissipation capacity and ductility are lower than those of the solid steel frame, but the ductility is still at high level. By analyzing ductility factor of hexagon hole and circular hole cellular steel frame under different expansion ratios, it fits out the relationship curvebetween expansion ratio and ductility factor. Weakening extent of the web holes can determine the ductility. Thus, by fitting the expansion ratio and ductility factor curve, with the relationship between seismic level and ductility in the passage, the expansion ratio limit value of two types of hole honeycomb cellular steel frame structures under different seismic levels has been proposed, which can provide a reference to the seismic design of cellular steel frame structure.