新型防屈曲高强钢腹板可更换钢连梁抗震性能研究

Seismic behavior of new buckling-resistant high-strength steel webs with replaceable steel coupling beam

文章率先提出一种新型防屈曲高强钢腹板可更换钢连梁(简称“新型钢连梁”):腹板采用高强钢,可提高钢连梁的屈服抗剪强度,连梁变形减小,从而减小可更换结构整体变形,便于更换;加劲肋紧贴腹板(但不焊接)提供约束,仅与上下翼缘焊接,可减少60%以上的焊接量。其次,设计并开展了11个试件的拟静力试验,研究了加劲肋间距(规范限值d_(max)、0.85d_(max))、腹板厚度(6mm、8mm)、腹板钢材强度(Q460、Q550)和构造形式(加劲肋与腹板贴紧或焊接)等参数对新型钢连梁抗震性能的影响。试验结果表明:试件均发生剪切破坏;满足加劲肋间距限值的新型钢连梁,滞回曲线饱满,峰值时腹板未发生鼓曲且极限转角均超过0.1rad,大于规范限值0.08rad,表现出良好的耗能和变形能力;缩小加劲肋间距、增加腹板厚度或提高腹板钢材强度,新型钢连梁刚度及承载力提高;新型钢连梁峰值承载力较传统构造试件低约5%。最后,基于试验结果建立了有限元模型并开展了分析,研究结果表明:对腹板采用Q460、Q550高强钢材的新型钢连梁,峰值承载力计算时超强系数建议取1.43(长度比为0.5~1.0)或1.39(长度比为1.0~1.6)、1.25,以期为实际工程设计提供依据。

This paper proposes a new type of buckling-resistant high-strength steel web replaceable steel coupling beam(BHCB).The web with high-strength steel can improve the yield shear strength of the BHCB, reduce the deformation of the coupling beam, and lead to a small deformation and facilitating replacement for the replaceable structure.The stiffeners are tightly attached to the web(but not welded) to provide the restraint.Since they are only welded to the flanges, the welding work can be greatly reduced.Eleven quasi-static tests were conducted to investigate the seismic behavior of BHCB with parameters of stiffeners spacing(d_(max), 0.85d_(max)), web thickness(6 mm, 8 mm), web steel strength(Q460, Q550) and construction form(stiffener tightly attached to the web or welded).The test results show that all the specimens failed in shear and no local buckling was observed at peak load for the BHCB when the stiffener spacing meet the code;the ultimate chord rotation of BHCB exceed 0.1 rad;the stiffness and shear capacity of BHCB can be increased when reducing the stiffener spacing, increasing the web thickness or the web strength;the shear capacity of the BHCB is 5% lower than that of the specimens with traditional web welding detail.According to the parametric study, for the BHCB with Q460 steel webs, the overstrength factor can be set as 1.45(length ratio is 0.5 to 1.0) or 1.4(length ratio beyond 1.0) respectively for calculating the shear capacity;while the overstrength factor can be set as 1.25 for Q550.