滑动节点板支撑钢框架(SGBFs)的抗震设计

Seismic Design of Sliding Gusset Plate Braced Frames(SGBFs)

滑动节点板支撑钢框架(SGBFs)是一种在中心支撑与节点板连接节点处引入对称摩擦装置的结构体系,在预期形成塑性铰位置的梁上设置可更换保险丝连梁,进而提供结构在大震下的变形能力。小震下,SGBFs保持弹性,通过刚度控制层间变形;中震下,SGBFs的摩擦装置开始工作,耗散能量并提供额外的阻尼,提高了系统的基本周期;大震下,摩擦装置继续工作,保险丝连梁进入塑性,从而保护主体结构免受损伤。震后,只需更换摩擦装置中的摩擦材料和保险丝连梁,达到快速修复、减少经济支出的目的。基于以上描述的性能目标,提出了SGBFs基于位移的抗震设计方法,设计了一座4层钢框架结构。通过Pushover分析、非线性时程分析与IDA(增量动力分析),系统地分析了SGBFs的抗震性能。结果表明,SGBFs能够达到预期的性能目标,塑性变形集中在摩擦装置与保险丝连梁,并且具有足够的抗倒塌能力。

Sliding Gusset Plates Braced Frames(SGBFs)is proposed in this paper.In this frame the braces are connected with the gusset plate using symmetric friction connections.In order to improve the deformation capacity of the system under rare earthquakes,the replaceable fuses are introduced in the beams at the locations where plastic hinges are expected.Under frequent earthquakes,the whole lateral system is in elastic stage with sufficient stiffness to control elastic inter-story drift.Under moderate earthquakes,the friction devices begin to slide,dissipating energy and providing additional damping.The fundamental period of the system is increased.Under rare earthquakes,the friction devices continue to work and the link fuses into plasticity,thus protecting the main frame from damage.Rapid recovery can be achieved by replacing the damaged fuses and friction shims to reduce cost.Based on the above performance targets,direct displacement-based design method for SGBFs is proposed.A four-story frame building model is designed.Pushover analysis,nonlinear time-history analysis,and IDA(incremental dynamic analysis)are conducted to study the seismic behavior.The results show that the SGBFs can achieve the performance targets,the plastic deformations are concentrated on the friction devices and replaceable fuse.Also the structure has sufficient collapse capacity.