含可更换剪切型耗能梁段的钢框筒结构抗震性能研究

地震作用下,传统钢框筒结构难以实现强柱弱梁的设计理念,大震下柱端往往先于梁端出现塑性铰。针对这一问题提出了含可更换剪切型耗能梁段的钢框筒结构,即在裙梁中设置可更换的剪切型耗能梁段,大震作用下结构利用剪切型耗能梁段良好的弹塑性变形能力进行耗能,其余构件仍处于弹性状态或部分发展塑性。设计了一组算例结构,包括传统钢框筒结构和含可更换剪切型耗能梁段的钢框筒结构,采用SAP2000有限元分析软件对算例结构进行了弹性和弹塑性地震反应分析,对比了传统钢框筒结构和不同耗能梁段布置形式的含可更换剪切型耗能梁段的钢框筒结构在多遇地震、罕遇地震和极罕遇地震作用下的抗震性能和破坏模式。结果表明:在裙梁中设置剪切型耗能梁段对结构整体刚度的影响较小,含可更换剪切型耗能梁段的钢框筒结构改变了传统钢框筒结构的耗能机制,主要通过耗能梁段的剪切变形代替裙梁端部塑性铰耗能。罕遇地震作用下耗能梁段全部进入塑性耗能,震后仅需替换损伤严重的耗能梁段即可快速恢复结构的使用功能。极罕遇地震作用下,传统钢框筒结构达到极限状态,而含可更换剪切型耗能梁段的钢框筒结构的耗能梁段进一步发展塑性,其余构件保持弹性,结构具有足够的安全储备。

Seismic Behavior Study of Steel Framed-Tube Structure with Replaceable Shear Links

Hinge formation occurs at the column-ends prior to those at beam-ends during severe earthquakes for conventional steel framed-tube structure(SFT),which is opposite to the"strong column/weak beam"design philosophy.Considering this limitation,this paper presents a steel framed-tube structure with replaceable shear links(SSFT).In SSFT,the replaceable shear link is placed at the middle of the spandrel beam.During severe earthquakes,the SSFT dissipates earthquake energy through the inelastic deformation of shear links,while other non-dissipative components are still elastic or slightly inelastic.A set of structures are designed in this paper,including one SFT and three SSFTs.The finite element models(FEMs)are built using SAP2000 software.Elastic and inelastic seismic response analyses for these models are investigated to compare their seismic performance and failure modes.The analysis results indicate that the shear links can be employed at the middle of spandrel beams as energy dissipation components,which has minimal effect on the lateral stiffness of the system.The energy dissipating mechanism of the SSFT is the shear deformation of the link,which could replace energy dissipating by the flexural hinge at beam-ends.All shear links are in inelastic under rare earthquakes,the function of the SSFT can be restored just by replacing the damaged shear links.The SFT reaches the ultimate state during extremely rare earthquakes while the SSFT just develops the plastic deformation at the shear link and other components are still in elastic range,which indicates that the SSFT is a safe structural system during rare earthquakes.