Buckling of a concentrically loaded imperfect elastic column with identical nonlinear rotational connections
Problem statement. The connections of the demountable metal frame systems are often made of a wedge or cup type. In such connections the dependence of the bending moment on the angle of mutual rotation of the elements is nonlinear. Currently there is no engineering methodology for assessing the bearing capacity of a pillar with non-linear rotational end connections. The purpose of this article is to develop an engineering methodology for determining the ultimate compression force for an elastic prismatic column with nonlinear rotational connections with monotonically decreasing stiffness. The objectives of the study are derivation of dependencies for the normal force in a centrally compressed beam-column with and without initial curvature, analysis of the established dependencies and obtaining a methodology for determining the ultimate compression force. Results. An approximate formula is obtained for determining the compression force in an elastic column depending on its bending stiffness, the length and initial curvature, the function of the bending moment and the angle of rotation at the ends. Conclusions. The significance of the obtained results for the construction industry lies in the fact that the proposed formula allows determining the ultimate compression force for an imperfect elastic prismatic column with identical nonlinear rotational connections with monotonically decreasing stiffness.