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为研究C型冷弯薄壁型钢压弯构件稳定性能,特别是其畸变屈曲性能,设计了38个冷弯薄壁卷边槽钢(C型钢)绕弱轴偏心受压短柱和中长柱试件,对其进行承载力试验,分析其破坏模式、极限承载力和变形性能。研究结果表明:正偏心受压试件的破坏主要由畸变屈曲模式控制,而典型的负偏心受压试件的破坏则主要受局部屈曲控制。对于中长柱试件,破坏还包含与整体屈曲的相关屈曲特征。正偏心受压试件承载力随腹板高厚比的增加而提高,而负偏心受压试件则呈现相反的规律。将试验结果和其他已有的试验研究数据与按GB 50018—2002《冷弯薄壁型钢结构技术规范》和北美(加拿大)规范S 136-12计算的试件承载力进行了对比,结果表明:对于负偏心受压构件,当应力不均匀系数ζ(截面上最小应力与最大应力的比值)趋于0并偏向负值(偏心距较大)时,随着ζ的减小,GB 50018—2002计算值与试验值的误差呈现逐渐增大的趋势,明显偏于不安全,当ζ≥-1.6时,按S 136-12对构件承载力的预估偏于安全;对于正偏心受压构件,当ζ≥-0.2时,GB 50018—2002和S 136-12对构件承载力的预估在多数情况下偏于保守,但其计算值离散性较大。
In order to study the stability of C-shaped cold-formed thin-walled steel members, especially their buckling buckling performance, 38 cold-formed thin-walled curled channel steel (C-section steel) The specimens were tested for their bearing capacity and the failure mode, ultimate bearing capacity and deformation performance were analyzed. The results show that the failure of the specimen with positive eccentricity is mainly controlled by the distorted buckling mode, while the failure of the typical negative eccentric compression specimen is mainly controlled by the local buckling. For medium-long column specimens, the damage also includes the buckling characteristics associated with the overall buckling. The bearing capacity of the positive eccentric compression specimen increases with the increase of the ratio of the height to the thickness of the web, while the negative eccentric compression specimen shows the opposite rule. The test results and other existing experimental data are compared with the bearing capacity calculated according to GB 50018-2002 Technical Specification for Cold-formed Thin-walled Steel Structure and North American (Canada) Specification S 136-12. The results show that: For the member with negative eccentricity, when the stress non-uniformity coefficient ζ (the ratio of the minimum stress to the maximum stress in cross-section) tends to zero and tends to negative (eccentricity is large), with the decrease of ζ, GB 50018-2002 The error between the calculated value and the experimental value tends to increase gradually, which is obviously unsafe. When ξ≥-1.6, the prediction of the bearing capacity of the member by S 136-12 is biased to be safe. For the member with positive eccentricity, When ζ≥-0.2, the prediction of bearing capacity of GB 50018-2002 and S 136-12 is conservative in most cases, but the calculated value is more discrete.