Analysis of the steel frames with the semi-rigid beam-to-beam and beam-to-column knee joints under bending and axial forces

This paper presents an analysis of framework structures with semi-rigid joints. The semi-rigid end-plate bolted joints are subjected to bending and tension or a compression axial force. Usually the influence of an axial force on joint rotational stiffness is neglected. In some cases, the level of axial forces in the joints of structures can be significant and has a profound influence on characteristics of semi-rigid joints. One of the most popular practical methods permitting the determination of rotational stiffness and moment resistance of a joint is the so-called component method. The extension of the component method for evaluating the influence of bending moment and axial force on the rotational stiffness and moment resistance of a joint and an application to the analysis of framework structures are presented in the paper. The numerical results of calculations of steel frameworks are presented in this paper as well. The study shows that the estimation of axial force influence to rotation stiffness characteristics of the joint has significant influence on the distribution of internal forces and displacements of steel framework.