短屈服段屈曲约束支撑钢框架抗震性能研究

Seismic behavior of steel frames with short yield buckling-restrained braces

屈曲约束支撑滞回性能优异,大量应用于中心支撑钢框架结构,可极大提高钢框架的抗震性能.但已有研究表明,当屈曲约束支撑钢框架遭遇罕遇地震时,结构产生较大的残余变形,导致震后更换支撑困难.为此提出了短屈服段屈曲约束支撑,并将其置于钢框架中进行动力时程分析.结果表明,短屈服段屈曲约束支撑钢框架的最大层间位移角较传统屈曲约束支撑钢框架最大降幅在10%左右,减小结构的残余层间位移角可达30%以上;在保证结构安全的同时,很大程度上提高了结构在震后的可修复性和遭遇二次地震时的可靠性,并且随着结构刚度的增加,额外的地震荷载几乎全由屈曲约束支撑承担,并不会给框架增加负担.

Buckling restrained braces(BRBs)have excellent hysteretic behavior.A large number of existing and newly constructed buildings use BRBs to improve the seismic performance of steel frames.However,previous studies have shown that the residual deformation of BRB steel frame can enlarge when encountering extreme earthquake,which makes the brace replacement difficult.In this paper,a BRB with short yield section is proposed and placed in a steel frame for dynamic time history analysis.The results show that,with the proposed BRB with short yield section,the maximum inter-story drift of the structure can be reduced by around 10%,causing the residual drift decreased to more than 30%.It not only ensures the structural safety,but also improves the repairability of the structure after the earthquake and the reliability when encountering the second earthquake.Moreover,with the increase of structural stiffness,the additional seismic load is almost entirely borne by BRBs,which does not increase the load on the frame.