均布荷载作用下腹板开孔轻钢龙骨墙体受弯性能试验研究

Experimental study on flexural behaviors of slotted light-gauge steel stud walls subjected to distributed loading

为研究腹板开孔轻钢龙骨墙体中覆面板材对墙体受弯承载力的贡献,考虑龙骨腹板高度、自攻螺钉间距等参数的影响,对5片腹板开孔的轻钢龙骨墙体标准单元在均布荷载作用下的受弯性能进行了试验研究,分析试件的承载力、破坏模式、挠度、应变和剪力滞效应等。基于试验结果,建立了可考虑剪力滞效应的腹板开孔轻钢龙骨墙体标准单元有限元模型,将试验结果与有限元计算结果进行对比,验证了模型的可靠性。基于有限元模型,研究了石膏板厚度、龙骨间距和腹板高度对石膏板有效宽度的影响。试验结果表明:开设细长孔洞对龙骨腹板削弱较大,会引起剪力滞效应,并导致墙体在均布荷载作用下在支座附近发生腹板的剪切屈曲;对于厚度为100~200 mm的墙体,竖龙骨与石膏板间的自攻螺钉间距取300 mm即可保证石膏板与龙骨共同工作;在开孔比率相同的前提下,随着腹板高度的增加,墙体抗弯刚度及受弯承载力均有显著提高。所建立的腹板开孔轻钢龙骨墙体标准单元实体有限元模型能够合理考虑剪力滞效应,与试验结果吻合良好,试件初始刚度和承载力预测值与试验结果最大相差分别不超过6%和4%。有限元参数分析结果表明石膏板有效宽度主要受龙骨腹板高度影响。

In order to study the contribution of gypsum boards to the flexural resistance of light-gauge steel framing(LSF)wall,five failure tests of LSF wall elements with slotted studs were carried out under uniformly distributed transverse loading considering parameters include the height of stud web and the spacing of self-tapping screws.Ultimate strength,failure mode,deflection,strain development and shear lag effect of test specimens were studied.Based on test results,a finite element model was developed and compared with test results for validation.Based on the finite element model,the influences of the thickness of gypsum board,the spacing and the web width of steel stud on the effective width of gypsum board were studied.The test results show that the slotted stud has much lower strength and stiffness,causing shear lag effect and shear buckling of the web near the ends of steel studs when subjected to distributed loading.When the wall thickness is in the range of 100 mm to 200 mm,the self-tapping screws can ensure that the gypsum boards and steel studs work as one unit with a spacing of 300 mm.When the slotting ratio remains unchanged,the flexural stiffness and bearing capacity of the wall elements can be increased effectively by increasing the web height of the slotted studs.It is also found that the finite element model can properly reflect the shear lag effect and agrees well with test results.For initial stiffness and ultimate strength of the wall elements,the maximum differences between finite element model predictions and test results are less than 6%and 4%,respectively.The parametric analysis results show that the effective width of gypsum board is mainly influenced by the web width of steel stud.