不同柱脚连接的自复位钢梁框架抗震性能试验

Experiment on seismic behavior of self-centering steel beam frame with different column foot connections

为研究不同柱脚连接形式对带自复位工字钢梁的单层单跨钢框架抗震性能的影响,设计制作了两个柱脚分别为固接和铰接的自复位框架试件,通过低周往复荷载试验,分析了试件的受力发展过程、承载力、滞回特性、延性、耗能能力及自复位能力.研究表明:柱脚固接的自复位钢框架,由于柱脚屈服后所需的恢复力远大于自复位工字钢梁提供的复位拉力,残余变形较大,结构自复位效果较差,因此不建议将其作为此类结构的柱脚连接形式;柱脚铰接的自复位钢框架在试验过程中的受力发展过程与理论分析结果吻合良好,仅耗能元件发生塑性变形,卸载后残余变形较小,具有“可恢复功能结构”的特点;柱脚铰接的自复位钢框架,在4%层间位移角时骨架曲线仍未出现下降段,承载力储备充足,试件的位移延性系数为3.1,等效黏滞阻尼系数为0.19,具有较好的抗震性能.

In order to study the influence of different column foot connections exerting on seismic behavior of single story and single span self-centering steel beam with I beam,two types of self-centering steel frame specimens composed of fixed column foot and articulated column foot respectively were designed and manufactured.The load transfer mechanism,bearing capacity,hysteretic behavior,ductility,energy dissipation capacity,and self-centering capacity of the specimens were analyzed by low cyclic loading test.Test results indicate that the self-centering frame with fixed column foot had larger residual deformation and poorer self-centering effect,since the required restoring force of the column foot after yielding was much greater than the force provided by the self-centering I beam.Therefore,it is not recommended to be adopted as column foot connection for such structures.The load transfer mechanism of the self-centering frame with articulated column foot agreed well with the theoretical analysis results.Only energy dissipation fuses had plastic deformation,and the residual deformation was small after unloading,indicating that it has the characteristic of“resilient structure”.When story drift was loaded to 4%,the skeleton curve had no descending section,and the self-centering frame with articulated column foot had adequate capacity reserve.The displacement ductility coefficient of the specimen was 3.1,and the equivalent viscous damping coefficient was 0.19,which shows that the structure has good seismic behavior.