The effect of relative rotation at joints on the critical load of asymmetric and non-sway one-story bending frame made up of composite members

In current work, the buckling behavior of asymmetric and non-sway one-story bending frame made up of composite members with transverse variation of mechanical properties subjected to axial compression without eccentricity is studied by using stability functions. It is assumed that members (beams and columns) with rectangular sections are produced by perfect connections of two various plates with the same widths and different thickness and elasticity modulus. The curvature of the plates are same as the curvature of the buckled member. The connection of the members at joints has relative rotation, therefore the frame has the semi-rigid connections. However results show that changes in thickness, length and the materials of layers in heterogeneous members do not affect the carry over and stiffness coefficients, but the buckling loads of this types of frames are dependent on mentioned parameters. In this paper, the buckling behavior of homogeneous and heterogeneous frames are compared. In the case of unchanged axial properties, the stiffness coefficient, modified stiffness coefficient and carry over moment factor are similar with the homogeneous members