冷弯型钢夹支薄板剪力墙在竖向荷载作用下抗火性能分析

为了得到冷弯型钢夹支薄板剪力墙的抗火性能,利用有限元软件ABAQUS建立7个夹支薄板剪力墙模型,分析了火灾下剪力墙的温度分布、轴压比、冷弯型钢边柱厚度和竖向加劲肋对墙体抗火性能的影响。研究表明,受火2h时,内嵌钢板温度为墙体最高受火温度的80％,边柱与竖向加劲肋背火面帽形截面腹板处的温度为受火面相应位置温度的1/4。随着轴压比的增大,墙体在火灾下的破坏位置上移,并由整体屈曲向局部屈曲转变。边柱壁厚对墙体的破坏形态与耐火极限有较大影响,建议选取边柱壁厚不小于2.5mm;有加劲肋的墙体可以利用加劲肋平衡钢板;过早屈曲所导致的不均匀拉力,对墙体在遭受火灾时产生的破坏具有一定的延缓作用。墙体发生弯曲的方向与边柱的承载能力有关,墙体发生弯曲时,边柱帽形截面的帽檐首先发生较大屈曲变形,随后全截面发生屈服。

Fire resistance analysis of cold-formed steel sandwich thin-plate shear wall under vertical loadings

In order to obtain the fire-resistance performance of cold-formed steel sandwich thin-plate shear wall, seven models of cold-formed steel sandwich thin-plate shear wall were established by using finite element software ABAQUS, and the temperature distribution of cold-formed steel sandwich thin-plate shear wall under fire, as well as the influence of axial pressure ratio, thickness of side columns of cold-formed steel sandwich thin-plate shear wall and vertical stiffeners on the fire-resistance performance of the walls were analyzed. The results show that the temperature of the embedded steel plate is 80% of the maximum temperature of the wall after it has been exposed to fire for 2 hours, and the temperature at the web of the hat shaped section on the back fire surface of the side column and vertical stiffener is about one fourth of that of the corresponding position of the fire surface. With the increase of axial compression ratio, the damage position of the wall under fire moves up and changes from global buckling to local buckling. The thickness of the side column has a great influence on the failure mode and fire resistance limit of the wall, and it is recommended that the thickness of the side column should be not less than 2.5 mm. The wall with stiffener can use vertical stiffeners to balance the uneven tension of steel plate caused by premature buckling of stiffener, which can delay the damage of the wall under fire. The bending direction of the wall is related to the bearing capacity of side column, and when the wall is bent, the hat brim of the side column first bends greatly, and then the whole section yields.