冷弯薄壁型钢梁-OSB板组合楼盖的抗弯刚度研究

Study on Flexural Stiffness of Cold-formed Thin-walled Steel Joists-OSB Composite Floors

通过对2块足尺冷弯薄壁型钢梁-定向刨花板(OSB板)组合楼盖的受弯承载力进行单调静载试验,分析了连接OSB板与冷弯薄壁型钢梁之间的螺钉间距对组合楼盖抗弯刚度的影响。采用拟正交异性板法计算了组合楼盖的抗弯刚度,在此基础上分析OSB板厚度、楼盖梁间距和截面尺寸等因素对组合楼盖抗弯刚度的影响,提出了常用冷弯薄壁型钢梁-OSB板组合楼盖的等效抗弯刚度计算方法。结果表明:试件的破坏模式主要表现为楼盖梁发生弯扭屈曲的同时,受压区翼缘、卷边及腹板出现相关屈曲破坏,屈曲波长为相邻螺钉间距;OSB板没有明显破坏;螺钉间距对组合楼盖的弹性抗弯刚度影响微小;在弹塑性阶段,随着螺钉间距的增大,组合楼盖的刚度退化明显增大。

Two full scale specimens were tested to study the flexural stiffness of cold-formed thinwalled steel joists-oriented strand board（OSB）composite floors,and the effect of the screw spacing between OSB and cold-formed thin-walled steel joists on the flexural stiffness of composite floors was analyzed.Meanwhile,authors used the proposed method of orthotropic plate to calculate the flexural stiffness of composite floors.Based on this,the influences of the thickness of OSB,the spacing and section dimension of joist,etc.on the flexural stiffness of composite floors were analyzed,and the equivalent flexural stiffness calculation method of the common cold-formed thin-walled steel joists-OSB composite floors was put forward.The results indicate the main failure modes of specimens are bending-torsion buckling of floor joists,and the relative buckling of compression flange,web and crimping.The wave length of bucking is the adjacent screw spacing.Then the OSB is not obviously damaged.Screw spacing almost has little effect to the elastic flexural stiffness of composite floors.However,in the elastic-plastic stage,with the increase of screw spacing,the stiffness degradation of composite floors increases significantly.