运用假想荷载法的钢结构直接分析法相关问题研究  

Research on related problems of steel structure direct analysis method using notional load method

作　　者：马飞 宋诗羽 张润雅 莫党生 Ma Fei;Song Shiyu;Zhang Runya;Mo Dangsheng(College of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]兰州大学土木工程与力学学院,兰州兰州730000

出　　处：《建筑科学》2022年第11期27-33,共7页Building Science

摘　　要：我国现行标准GB 50017—2017、欧洲标准EN 1993-1-1:2005、美国标准ANSI/AISC 360-16均推荐使用假想荷载法考虑初始缺陷,而GB 50017—2017新加入的直接分析法与初始缺陷是分不开的。基于直接分析法软件NIDA,对在采用GB 50017—2017、EN 1993-1-1:2005、ANSI/AISC 360-16标准推荐的初始缺陷考虑方法下的经典算例直接分析的计算结果进行分析。由结果分析得知,标准中对构件施加均布荷载和支座反力等效构件初始缺陷的方法存在缺陷。本文通过计算不同类型框架节点下的框架柱剪力,发现框架节点刚度的不同会导致支座反力分配不均等,若按标准每层均等分配支座反力会出现支座反力的冗余,导致框架直接分析侧移结果偏小。通过对考虑初始缺陷的框架与仅考虑结构初始几何缺陷的框架进行计算对比,本文建议在需要得到框架的侧移结果时,仅需对结构施加假想水平荷载,而计算内力结果时,可按标准中假想荷载法的规定计算。China’s current standard GB 50017-2017, European standard EN 1993-1-1: 2005 and American Standard ANSI/AISC 360-16 all recommend the use of notional load method to consider the initial imperfections, but the direct analysis method newly added in GB 50017—2017 is inseparable from the initial imperfections. Based on the direct analysis software NIDA, the calculation results of the direct analysis of the classical examples using the initial imperfection consideration method recommended by GB 50017—2017,EN 1993-1-1: 2005 and ANSI/AISC 360-16 standards are analyzed. According to the analysis of the results, the method of applying uniform load and support reaction force to equivalent initial imperfections of members in the standard has defects. In this paper, by calculating the shear force of frame columns under different types of frame joints, it is found that the different stiffness of frame joints will lead to unequal distribution of support reaction force. If the support reaction force is evenly distributed at each layer according to the standard, there will be redundant support reaction force, leading to the small lateral displacement results of direct analysis of frame. Through the calculation and comparison of the frame considering the initial imperfections and the frame considering only the initial geometric imperfections of the structure, it is suggested that when the lateral displacement results of frames need to be obtained, only the notional horizontal load should be applied to the structure, while the internal force results can be calculated according to the provisions of the notional load method in the standard.

关 键 词：直接分析法 钢结构 初始缺陷 标准 假想均布荷载与支座反力 剪力分配 

分 类 号：TU391[建筑科学—结构工程]