Z形截面檩条强度计算时的下翼缘假想水平荷载  

NOTIONAL LOAD ON BOTTOM FLANGE IN STRENGTH CALCULATION OF Z-SHAPED CROSS SECTION PURLIN

作　　者：童根树[1] 吴强[1] 

机构地区：[1]浙江大学建筑工程学院,杭州310058

出　　处：《工业建筑》2012年第4期136-142,共7页Industrial Construction

摘　　要：假设屋面板与檩条采用自攻螺钉连接从而能够避免上翼缘的侧向位移。对此种连接的冷弯Z形截面檩条,在不设置拉条、风吸力作用下的应力和变形,采用薄壁构件约束扭转理论进行分析,并与采用ANSYS板壳单元的计算结果和EC3的方法进行对比,发现三者吻合非常好。通过分析发现,EC3的方法中,其下翼缘假想水平力计算公式的两个组成部分是:1)荷载偏离截面剪心产生的扭矩用平行于上、下翼缘的一对力来代替;2)绕平行轴的弯矩产生的应力采用简单的公式计算,等同于人为引进了水平弯矩,这个弯矩必须采用假想水平荷载来抵消。Lateral displacement of the top flange of purlins is prevented by self-drilled screw connections between roof sheet and purlin.Such connected cold-formed Z-shaped cross section purlins,with no anti-sag bars,was analyzed for stress and deformation under the suction effect of wind,using the theory of thin-walled bars.The results are found to be in excellent agreement with results of ANSYS shell element calculations and the method in EC3.Further analysis revealed that the horizontal notional load at the bottom flange introduced in EC3＇s approach,consists of two parts：1） one is to replace the torque generated by load not passing through the shear center,2）the other is to offset the horizontal moment caused by the simplified calculation of stress around parallel axis.

关 键 词：檩条 应力 扭转 假想荷载 强度 

分 类 号：TU392.5[建筑科学—结构工程]