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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。
It is assumed that roofing and purlins are self-tapping screws to avoid lateral displacement of the upper flange. For the cold-formed Z-section billet of this kind of connection, the stress and deformation under the condition of no bracing and wind suction are analyzed by the theory of restrained torsion of thin-walled members, and compared with the calculation results of ANSYS plate-shell unit and EC3 Method to compare and found that the three agree very well. It is found through analysis that two components of the formula for calculating the imaginary horizontal force of the lower flange in the EC3 method are as follows: 1) The torque generated when the load deviates from the shear center of the section is replaced by a pair of forces parallel to the upper and lower flanges; 2) The stress generated by bending moments around parallel axes is calculated by a simple formula, which is equivalent to the introduction of horizontal bending moment artificially. This bending moment must be offset by the imaginary horizontal load.