【摘要】 钢结构中心支撑框架是多层工业和民用建筑中广泛应用的抗侧力结构体系之一,其在地震动激励下的抗震问题十分复杂。为此讨论钢结构中心支撑框架的抗震承载力设计。首先,讨论我国抗震规范的中心支撑抗震承载力验算公式,指出其不可靠,过高估计了支撑屈曲后承载力。在与相关国外规范和试验数据比较的基础上,提出了更可靠、合理且简捷的支撑承载力验算公式。继而,讨论了支撑计算长度以及V和Λ形支撑横梁设计需特别注意的问题。最后,就中心支撑框架抗震承载力设计的问题进行讨论,指出,支撑设计应考虑支撑对支撑系统中钢柱轴力的影响和在地震作用组合下支撑屈曲与否的影响,并提出了建议设计方法,可供规范修订时参考。更多还原

【Abstract】 Concentrically braced steel frame is one of the lateral force resisting systems widely used in multi-storey industrial and civil buildings, and exhibits complicated seismic behavior under earthquake excitations. This paper discusses the seismic strength design of concentrically-braced frames. The equation for the compression strength calculation of concentrical braces under seismic conditions as prescribed by the Chinese seismic code is questioned and it is pointed out that the equation is unreliable and may over-estimate the strength capacities of braces. An equation which is deemed more reliable, appropriate yet concise for seismic strength verification is proposed based on a comparison with corresponding foreign codes and experimental results. Consequently, the effective (calculation) length of braces and a particular problem deserving attention for the horizontal beam design of V-and Λ-type (chevron) braces are discussed. Finally, the issue on the seismic design of concentrically-braced frames is discussed. It is pointed out that the effects of braces on the axial force of brace system columns and whether braces buckle or not under seismic action combinations should be considered, and recommendations are presented accordingly.更多还原