风吸力下蒙皮支撑Z形檩条临界荷载的简化计算方法  

Simplified Approach for Calculating the Critical Load of Z-Shaped Purlin Braced by Skin Diaphragm under Wind Suction

作　　者：钱宏亮[1,2] 黄壮[2] 张耀春[1,2] 王幼清[1,2] 

机构地区：[1]哈尔滨工业大学土木工程学院,哈尔滨150090 [2]哈尔滨工业大学(威海)土木工程系,山东威海264209

出　　处：《建筑钢结构进展》2017年第4期28-35,共8页Progress in Steel Building Structures

摘　　要：檩条在实际应用中总是受到屋面板对它的侧向支撑和扭转约束作用,即蒙皮支撑作用。工程设计时考虑风吸力下蒙皮对檩条的支撑作用能够有效降低经济成本,但是目前我国有关规范给出的设计算法过于复杂,极大地降低了工程设计效率。引入经典的有限元模型,采用参数分析方法,讨论了檩条腹板高厚比、檩条翼缘宽厚比、檩条侧向长细比、蒙皮对檩条的扭转约束刚度4种参数对风吸力下Z形檩条弯扭屈曲临界荷载的影响。在参数分析的基础上,提出了一个考虑蒙皮支撑作用的风吸力作用下Z形檩条临界荷载简化计算公式。对比简化公式算法与我国门式刚架规程算法,发现两种方法计算结果非常接近,且与有限元分析结果相近,验证了公式的准确性。简化算法过程和形式简单,能高效准确地获得蒙皮支撑的Z形檩条在风吸力作用下的临界承载力,可提高工程设计效率。Purlin is subjected to lateral support and torsional constraint from the roof sheeting in practical applications.This is so-called bracing effect of skin diaphragms.This can effectively reduce the costs of engineering design.However,the current design standard for the bearing capacity of purlin braced by skin diaphragm under wind suction is too complicated and this reduces design efficiency significantly.This paper introduces a classic finite element model,then four parameters are studied under wind suction on the critical load of flexural-torsional buckling for Z-shaped purlins.These four parameters are purlin web depth-thickness ratio,purlin flange width-thickness ratio,purlin lateral slenderness ratio and torsional constraint stiffness.Finally,a simplified formula for the critical load of Z-shaped purlins is proposed,accounting for the diaphragm effect under wind suction.The accuracy of the formula is verified by comparing the result from simplified formula and the result from relevant Chinese standard and also finite element analysis.The study shows among the above methods,the calculation of the simplified formula is more concise,and thus it can improve the efficiency of engineering design significantly.

关 键 词：蒙皮支撑效应 风吸力 Z形檩条 临界荷载 简化公式算法 

分 类 号：TU391[建筑科学—结构工程]