K型偏心支撑钢框架支撑的设计研究

Brace design of K shape eccentrically braced steel frames

为研究不同支撑刚度K型偏心支撑钢框架的抗震性能,对5个具有不同支撑截面的试件进行了非线性有限元分析。结果表明:为保证耗能梁段先行剪切屈服而支撑不屈曲,支撑应具有足够的刚度;支撑长细比较小的试件滞回性能较好,而长细比过小则会降低结构的延性和耗能性能;对于长细比较小的支撑,其翼缘宽厚比应严一些,而腹板高厚比则可适当放宽;支撑斜杆与横梁的连接焊缝发生断裂破坏的可能性较大,在施工中应对该处焊缝的焊接质量进行严格控制。并根据有限元模拟结果提出了设计和施工建议。

In order to study seismic-resistant characteristic of K shape eccentrically braced steel frames, nonlinear finite element analysis for five samples with different sections was performed. Analysis indicates that： （ 1 ） to ensure the link yield before the buckling of brace, the brace should have enough rigidity, （2） the brace with smaller ratio of slenderness has better hysteretic behavior, and structural ductility and energy-dissipation performance will decrease if the ratio of slenderness is too small, （3） to brace with smaller ratio of slenderness, the flange ratio of width to thickness should be emphasized while the web ratio of height to thickness should be enlarged, （4） the quality of weld should be controlled strictly, because the weld in the connection of brace and transverse beam is in high possibility of rupture. Suggestions on design and fabrication based on the finite element simulation results are presented.