- 摘 要
-
(1 同济大学建筑工程系 上海 200092; 2 汕头大学土木工程系 515063)|
[提要]推导了考虑连接柔性和几何非线性的局部坐标下的单元刚度矩阵,并对半刚性连接单元的固端力进行了修正;采用增量加载法中的修正NewtonRaphson法,给出了考虑连接柔性、框架的几何非线性和单元内力与连接之间耦合效应的半刚性钢框架结构分析计算机流程。采用Frye和Morris的奇次方多项式模型来模拟连接的M-θ曲线。最后根据算例对有侧移和无侧移半刚性钢框架的性能做了初步的探讨,结果表明:1)半刚性连接会明显加大有侧移钢框架的侧向位移和结构的二阶效应;2)半刚接对梁柱的轴力和剪力影响都不大,但对梁柱的弯矩影响则较大,半刚性连接会减小无侧移钢框架的柱脚弯矩而增大有侧移钢框架的柱脚弯矩,但无论是无侧移还是有侧移钢框架,半刚性连接都会增大梁的跨中弯矩;3)当连接转动刚度Rk在10×108~10×1011(N·mm/rad,以下同)之间时,连接呈现出较为明显的半刚性特性,而当Rk<10×108或Rk>10×1011时,连接的半刚性特性并不明显,可直接将其看作铰接或刚接以简化计算。
[关键词] 半刚性 钢框架 单元刚度矩阵 二阶效应 转动刚度
Analysis and Behaviour Research of Connections of Semi rigid Steel Frame/
Huang Jizhuo1, Wang Zhan2, Ma Renle1(1 Department of Building Engineering, Tongji University,Shanghai 200092,China; 2 Department of Civil Engineering,Shantou University, Shantou 515063,China)
Abstract:Element stiffness matrix in local coordinate system is derived, which takes the effects of the flexibility of the connections and the geometric nonlinearity of the members into account, and then fixedend forces with semirigid connections are modified. A computerbased procedure with incremental loading method is presented for the analysis of semirigid steel frames, which accounts for the effects of the nonlinear behaviour of the connections and P-Δ as well as the coupling effect of element forces and connections. The Frye and Morris polynomial model is adopted for modeling the semirigid connections. Frames with and without displacements are presented to demonstrate the validity and effectiveness of the analysis procedure for semirigid steel frames, and to reveal the internal law of semirigid steel frames comparing with fullyrigid or ideallypinned steel frames.Semirigid connections will increase the lateral drifts of steel frames distinctly and magnify the P-Δ effect.Semirigid connections have little effect on memberend axial and shear forces, but have considerable influence on memberend moments. Connections with rotational stiffness ranging from 10×108 to 10×1011(N·mm/rad) exhibit the obvious semirigid behaviour, and it is suitable and convenient for calculation to treat connections with rotational stiffness out of the above range as fullyrigid or ideallypinned connections.
Keywords:semirigid;steel frame;element stiffness matrix;secondorder effect;rotational stiffness