基于二阶假想荷载法的直接分析法研究  

Research on Direct Analysis Method Based on Second-Order Notional Load Method

作　　者：马飞 刘占科[1] MA Fei;LIU Zhanke(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730000

出　　处：《建筑钢结构进展》2022年第10期59-67,共9页Progress in Steel Building Structures

基　　金：国家自然科学基金(51308272);兰州大学中央高校基本科研业务费专项资金(lzujbky-2021-kb03)。

摘　　要：《钢结构设计标准》(GB 50017—2017)加入了直接分析法这一新的内容,此类方法重要的一环是对初始缺陷的考虑。重点总结归纳了中国、美国、欧洲的现行钢结构规范所推荐且运用方便的“假想荷载法”的基本原理。从假想荷载法的不足出发,针对《钢结构设计标准》(GB 50017—2017),令具有初始几何缺陷的轴压构件的最大二阶弯矩等效于受假想力作用的理想轴压构件的最大二阶弯矩,推导出了使用假想力来考虑初始缺陷的“二阶假想荷载法”的计算式,并从理论出发定义了计算式的物理量以及二阶假想荷载的施加方式。用直接分析法软件NIDA对经典算例进行二阶弹塑性分析。通过对比不同规范的计算结果,验证了该方法的可靠度以及“假想荷载法”的不足,让传统的设计理念更好地和直接分析法衔接起来,推动新设计方法的应用。Standard for Design of Steel Structures(GB 50017—2017)introduces a new part on direct analysis method;the correctness of the results of such approaches relies mostly on the initial imperfections being considered. This paper summarizes the fundamental concepts of the "notional load method",which is recommended by contemporary steel structural standards in China,the United States,and Europe and is easy to implement. In this paper,the maximum second-order bending moment of an axial compression member with an initial geometric imperfection is equal to the maximum second-order bending moment of an ideal axial compression member subjected to the notional load. From this,the calculation formula of "second-order notional load method",which uses notional force to account for initial imperfection,and the software NIDA is used to conduct the second-order elastic-plastic analysis of the standard calculation example. By comparing the calculation results of various specifications,the reliability of this method and the deficiency of the "notional load method" are examined,allowing the traditional design concept to be more closely aligned with the direct analysis method and promoting the use of the new design method.

关 键 词：直接分析法 钢结构 初始缺陷 假想荷载法 二阶假想荷载法 

分 类 号：TU391[建筑科学—结构工程]