带屈曲约束支撑的V型偏心支撑钢框架抗震性能分析

SEISMIC PERFORMANCE ANALYSIS OF V-SHAPED ECCENTRICALLY BRACED FRAMES WITH BUCKLING-RESTRAINED BRACES

偏心支撑钢框架主要通过耗能梁段发生剪切屈服变形来耗散地震能量,其支撑斜杆必须不发生屈曲才能保证耗能梁段能够耗能。对于跨度较大的结构,支撑斜杆为了满足稳定性与轴压比限值的要求,截面需要很大,结构经济性不好,同时也导致地震作用下内力增大。将偏心支撑钢框架的支撑斜杆换成屈曲约束支撑,进行有限元分析,结果表明:罕遇地震作用下,带屈曲约束支撑的V型偏心支撑钢框架侧向位移比普通支撑钢框架最大减小22.15%,有效地控制了结构的侧移;能量时程图表明:屈曲约束支撑消耗了大部分地震能量,屈曲约束支撑和耗能梁段能够同时参与耗能,建立起结构抗震的多重防线。

Eccentrically braced frames can dissipate earthquake energy through the shear yield deformation of energydissipation beam segments. The diagonal braces must not produce buckling to ensure the energy dissipation capacity. For the long-span structure,enlarging the cross-section of diagonal braces to meet the requirements of stability and axial compression ratio limiting value is necessary. It＇s not economic,and may lead to an increase of the internal force of the structure under seismic loading. The eccentrically braced frames adopted Buckling-restrained braces instead of the diagonal braces. Through the finite element analysis,the results showed that the lateral displacement of V-shaped eccentrically braced frames with Buckling-Restrained Braces decreased by 22. 15% than ordinary eccentrically braced frame under sever earthquake,and effectively controlled the lateral displacement of the structure; the energy schedule chart indicated that Buckling-Restrained Braces consumes most of the seismic energy. Buckling-Restrained Braces and the energy-dissipation beam segments could dissipate energy at the same time,so as to set up multiple seismic-proofs.