节点板式连接对H形钢支撑面外稳定性能的影响

为研究节点板对H形支撑面外弯曲约束能力和对支撑稳定承载力的影响规律，设计并制作了12个带有节点板的H形支撑(支撑系统)模型试件。进行了轴向等幅往复循环加载条件下的试验研究，得到了支撑端部的节点板连接净距等对支撑稳定承载力的影响规律，建立了往复循环加载条件下受压时支撑稳定承载力的退化准则和屈曲后承载力的建议取值方法。使用有限元方法对试验结果进行了精细化数值模拟，二者吻合效果良好。据此，对带有节点板的支撑系统进行了足尺模型的大规模参数分析。结果表明，支撑长细比、节点板厚度、支撑端部的节点板净距、支撑与梁柱夹角等参数对支撑稳定承载力和节点板面外转动刚度具有显著影响。基于这些关键参数对支撑端部弯曲约束能力的影响规律，并考虑尺寸效应，给出了板式连接节点对支撑面外转动刚度和支撑计算长度系数的建议取值公式，可以用于支撑的稳定承载力计算。

RESEARCH ON THE INFLUENCE OF GUSSET PLATE CONNECTIONS ON THE OUT-OF-PLANE STABILITY OF THE H-SHAPED STEEL BRACE

Experiments on 12 specimens of H-shaped steel bracing members with gusset plate connections (brace system) are conducted to study the effect of gusset plate on the out-of-plane rotational restraint and stability capacity of the brace. The experiments are under cyclic loading with constant-amplitude axial displacement, and the effect of clearance distance on the stability capacity of the brace is obtained. For the cyclic constant-amplitude loading condition, the degradation criterion of stability capacity of the brace system is obtained and the calculation formula of the post-buckling capacity is suggested. The finite element method is used to simulate the behaviors of specimens, and the simulated results are in good agreement with the experimental results. Moreover, a large-scale parameter analysis of the full-sized brace system is carried out. The results indicate that the brace slenderness ratio, the thickness of the gusset plate, the clearance distance and the brace angle have significant impacts on the out-of-plane rotational stiffness and stability capacity of the brace system. Based on the influence of these critical parameters on the rotational restraint of gusset plate and considering the size effect, the formulas for calculating the rotational stiffness of the gusset plate connection and the effective length factor of the brace are proposed, which can be used to easily obtain the stability capacity of the brace system.