不同规范中雪荷载作用下门式刚架静力响应和稳定性研究

RESEARCH ON STATIC RESPONSE AND STABILITY OF GABLE FRAMES UNDER SNOW LOAD BASED ON DIFFERENT LOAD CODES

对ISO、中、美、加、欧规范中门式刚架屋盖结构受到雪荷载作用时的响应进行比较。运用有限元软件ANSYS,对不同坡度的变截面门式刚架在5种规范不同积雪分布形式下的静力响应进行分析,并计算考虑不同初始缺陷幅值的结构整体稳定临界荷载因子,总结雪荷载作用下门式刚架的失稳特点。分析结果表明:门式刚架的基底剪力、跨中竖向位移、临界荷载因子与雪荷载总量密切相关;各规范下非均匀雪荷载较均匀雪荷载作用下柱顶水平位移大;结构稳定性随初始缺陷幅值增大而降低,随屋面坡度增大而增大,对缺陷不敏感;非均匀雪荷载更容易使结构发生有侧移失稳。

This paper compares the responses of gable frames subjected to snow load under ISO, China, USA, EU and Canada load codes. The static responses of structure with different values for slopes are analyzed using the FEA software, ANSYS, considering different initial imperfection. Global stability critical load factor of gable frame structure with tapered members are obtained under different distribution forms of snow load. Stability behaviors of gable frames under snow load are revealed. The analysis shows that the base shear, the mid-span vertical deflection and the load factor of gable frames are closely related to the total snow load; the horizontal displacement at the top of column subjected to the unbalanced snow load is larger than the balanced snow load under all the load codes; gable frame with larger initial imperfection amplitude and lower slope has worse stability, and gable frame is not sensitive to initial geometric imperfections; under unbalanced snow load, asymmetric instability is more likely to occur.