简支Z型檩条在风吸力作用下应力分布及极限状态研究  

Analytical method for simply supported Z-section purlins under wind uplift loading

作　　者：白凡[1,2] 杨娜[1] Bai Fan1,2 Yang Na1(1. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China; 2. Beijing＇s Key Laboratory of Structural Wind Engineering and Urban Wind Environment, Beijing Jiaotong University, Beijing 100044, Chin)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]北京交通大学北京市结构风工程与城市风环境重点实验室,北京100044

出　　处：《土木工程学报》2018年第4期55-61,共7页China Civil Engineering Journal

基　　金：国家自然科学基金优秀青年基金项目(51422801);北京市自然科学基金重点项目(8151003);高等学校学科创新引智计划(111计划)(B13002)

摘　　要：轻钢工业厂房中,Z型檩条在其截面的非对称平面内承受风荷载,上翼缘受压型钢板连续约束作用而下翼缘自由,应力分布比较复杂,存在局部或整体稳定问题,是围护结构抗风设计的主要控制因素。基于薄壁杆件结构力学以及经典梁理论,分析了简支Z型檩条在风吸力作用时考虑压型钢板对檩条约束作用的应力分布,并依据相关试验资料,验证了分析方法的正确性。然后,针对檩条横截面应力分布、侧向位移及极限状态等力学性能进行定性参数分析。研究表明,该方法可以精确计算檩条横截面应力分布,压型钢板对檩条的扭转及侧翼约束作用分别影响檩条上、下翼缘的峰值应力,使得构件局部屈曲应力增大,而畸变屈曲应力降低,从而改变檩条局部失稳模式,使得檩条由局部屈曲失稳转变为畸变屈曲失稳。With the sheeting of the upper flange continuously restrained and the lower flange kept free, the stress distributions in the non-symmetric plane of the Z-section purlins appeared to be complicated, leading to the global or local instability problems at the web and lower flange. To address this problem, a semi-analytical model of predicting the longitudinal stresses of Z-section purlins considering both the lateral and rotational restraints imposed by sheeting under wind uplift. To calculate the longitudinal stresses of the roof purlins, formulas are derived based on the classical bending theory of the thin-walled beams. Test data collected from existing literatures are adopted to validate the model. It is shown that the results predicted by the proposed model agree well with the collected test data. Furthermore, the parameter analysis on the limit states of strength and stability considering the lateral bracing are conducted. The results show that the present model can be used to calculate the longitudinal stress distribution and the displacement; the stress distributions at the upper and lower flanges may vary with the change of the stiffness of restraint, so that the instability mode of purlins may switch from the local buckling to the distortion buckling.

关 键 词：檩条 风吸力 应力 极限状态 损伤评估 

分 类 号：TU391[建筑科学—结构工程]