摘要
钢管混凝土束墙是我国发明的一种新型抗侧力构件,它从矩形钢管开始,向一个方向焊接一个个冷弯宽翼缘卷边U形钢,形成一字形多腔钢管墙,并在现场浇筑混凝土,形成多腔钢管-混凝土组合墙。目前一字形钢管混凝土束墙的弯扭失稳公式直接引用了箱形柱的相应公式,尚缺乏深入的研究。为此对一字形钢管混凝土束墙截面压弯墙绕弱轴的弯扭屈曲承载力验算公式进行了理论研究,主要工作如下:(1)对一字形钢管混凝土束墙绕强轴和绕弱轴两个方向的单向压弯强度公式进行了推导,研究了束墙退化成夹层板时绕强轴和绕弱轴的轴力-弯矩相关公式,对钢管混凝土束墙的单向压弯强度公式进行了拟合;(2)对给定压力时双向弯矩作用下的塑性铰状态的双向弯矩相关关系进行了计算,提出了精度良好略偏安全的公式;将提出的公式进行改造,使之能够考虑双力矩的影响;(3)参照压弯杆平面内稳定验算公式的推导方法,利用已知的绕弱轴弯曲屈曲的柱子稳定系数公式,将初始弯曲和二阶弯矩代入绕弱轴的强度相关关系,反推获得了压杆绕弱轴弯曲屈曲的等效初始弯曲,该等效初始弯曲综合考虑了残余应力、初始弯曲和塑性开展过程带来的额外挠度增量;(4)对有初始弯曲和扭转压弯杆的弹性弯扭变形进行了二阶分析,在引入初始弯曲和初始扭转的特定关系后,得到了二阶效应放大后的弯曲、扭转、弯矩和双力矩的简单的解析表达式;(5)考察了钢管混凝土束墙纯弯时的弯扭屈曲承载力,发现即使弯曲失稳的长细比达到1.6,弯扭屈曲的长细比仍小于0.5,因此束墙的纯弯承载力可以达到塑性弯矩;(6)引入等效初始弯曲,采用平面内二阶分析获得的二阶弯矩,平面外二阶弯矩和二阶双力矩等,代入双向压弯强度计算式,得到压弯杆弯扭屈曲承载力的上限解。为了获得更为接近实际的承载力�
Concrete-filled multicellular steel tube walls(CFT-walls)are a newly-developed lateral-force-resisting member in China,it begins with a cold-formed rectangular box,and then added by a series of cold-formed lipped wide-flange U-section in a direction to form a multicellular steel tube wall,concrete is filled-in-situ to form a multicellular CFT-wall.The current equation used in the design of CFT-walls for flexural-torsional buckling is from steel box column,detailed study is lack.This paper presents a study on the flexural-torsional buckling of CFT-walls under axial force and in-plane bending moment,the main works are as follows:(1)As the first step of the development,plastic interactive relations are derived for the axial force and bending moments about the strong axis and about the weak axis respectively.When the CFT-walls are degenerated into a sandwich cross-section with two face steel plates and a concrete mid-layer,explicit expressions are obtained for these two interactive relations.Based on these expressions,fitting curves with good accuracy are provided for them.(2)For the general cases of axial force and biaxial bending moments,exact analysis is carried out for the state of spatial plastic hinges and an approximate interactive equation for biaxial bending under a given axial force is also proposed.The effect of bi-moment is incorporated into the proposed equation.(3)Based on the codified column strength reduction factor,the equivalent initial out-of-plane deflections are obtained by taking the buckling strength of the column about the weak axis as a plastic hinge state under the axial force and the amplified bending moment due to the second order effect and initial deflection,this equivalent initial deflection includes the effect of residual stress,initial deflection and the additional deflection increment due to plasticity development.(4)Second-order analysis is carried out for the walls with initial deflection and initial twisting,after introducing a specific relation between the initial deflection and
作者
童济
童根树
Ji Tong;Genshu Tong(The Architectural Design and Research Institute of Zhejiang University,Hangzhou 310058,China;Institute of High Performace Structures,Zhejiang University,Hangzhou 310058,China)
出处
《钢结构（中英文）》
2022年第11期1-23,共23页
Steel Construction（Chinese & English）
关键词
弯扭屈曲
压弯杆
钢管混凝土束墙
二阶效应
flexural-torsional buckling
beam-column
multicellular CFT-walls
second-order effect
