This paper proposes a method to establish the geometric stiffness matrix and stiffness matrix for semirigid beam element and semirigid beam element with rigidzones. The proposed method can also applied to analyse frame stability with rigid, sernirigid and simple connections with rigidzones or without rigidzones. | Vietnam Journal of Mechanics, NCST of Vietnam Vol. 23, 2001 , No3 (134 - 148) STABILITY ANALYSIS OF STEEL FRAMES WITH SEMIRIGID CONNECTIONS AND SEMIRIGID CONNECTIONS WITH RIGIDZONES Vu Quoc ANH Faculty of Civil Engineering - Ha noi Architectural University ABSTRACT. To obtain an accurate insight into the behavior of most realistic steel frames, joint flexibility should be allowed for in the analysis since connection flexibility affects both force distribution and deformation in beams and columns of the frames . This paper proposes a method to establish the geometric stiffness matrix and stiffness matrix for semirigid beam element and semirigid beam element with rigidzones. The proposed method can also applied to analyse frame stability with rigid, sernirigid and simple connections with rigidzones or without rigidzones. In addition, an approach that evaluates t he effective lengthµ factor, the critical axial load of column in plane frames with rigid, semirigid, and simple connections is also presented: 1. Introduction In the majority of civil engineering structures and building, the fabrication of a near fully rigid joint is expensive, impractical and economically unjustifiable in most cases. In reality, connections in steel frames are mostly semirigid and, consequently, the force and bending moment diagrams constructed under the rigid or pinned joined assumption contains a considerable error. The design based on these results will also lead to an inappropriate sizing of the members. In current engineering practice, the determination of the effective length factors of columns must be made in order to design semirigid frames to ensure accuracy. A major limitation of the column µ factor obtained from current methods is that they are not applicable to frames with semirigid connections and semirigid connections with rigidzones, but to perfectly rigid or simply connected frames. Therefore, there is a real need for a comprehensive and practical approach, preferably .
