Analysis Of Mechanical Properties Of Buckling Restrained Brace And Application In Steel Frame

In Northridge earthquake (1994) and Hyogo-ken earthquake (1995), a large amount of destruction appeared in the building of this kind of system. Studies have suggested, because of brace buckling early, the strength of sturucture was dropped. In order to improve the buckling performance of brace, make in earthquake occurrence, no buckling of brace will take place, as to traditional concentrically braced frame put forward a new system can avoid brace buckling, called buckling restrained braced frame. This system is a large amount of adopt already in Japen and U.S.A., demonstrates good anti-seismic performance.First, the bearing performance under horizontal low cycle loading of Buckling Restrained Brace with rectangle section core was analyzed used commercial software ANSYS. The distribution of internal forces of BRB were studied and high-order mode buckling process was tracked down. The results demonstrate a stable hysteretic behavior of brace. The influence on internal forces of gap between core steel-plate and exterior concrete as well as friction force of BRB were obtained through analysis. Fourteen models with different gaps and five models with different friction coefficient have been calculated. The results imperative that reasonable gaps should be confirmed and minish friction .Second, a new type doube tube BRB was analyzed. The analysis results also indicate, this kind of buckling restrained brace having good dissipation energy ability. Considered all kinds of nonlinearity, the influence of restraining ratio and initial imperfection on ultimate load, the influence of restraining ratio on hysteretic behavior of BRB were studied, a reasonable restraining ratio was suggested, with that restraining ratio BRB can work well and economically.On this basis, the further research of anti-seismic of buckling restrained braced frame was performed. Traditional braced frame and BRB braced frame were compared both in monotonic and cyclic loading. Example proved, as to concentrically braced frame, buckling restrained braced frame has better anti-seismic performance. Meanwhile, the study of impact on structural anti-seismic with different layouts of BRB was also performed.