Stability Analysis of Frames

In the previous chapters the stability of column, and beam-column was examined by treating them as independent or isolated members with appropriate boundary conditions. The simple frames have been treated as struts or beam-columns with elastically restrained ends wherein the effect of the connecting members has been modelled by end springs. However, in practice the columns, beams, and beam-columns are normally rigidly joined together to make skeletal structure called a frame in which the total structure is called upon to withstand the applied loads. In these rigid jointed frames, the end conditions of a member and hence its effective length depends upon the relative stiffness of the members meeting at the ends and that of member itself. Moreover, in a frame the deflection even in a single member due to buckling causes distortion in all the members. Thus, the response of the frame needs be examined in its totality wherein actual buckling of total frame is considered. In this chapter the stability analysis of the frames using classical differential equation method, semi-geometrical method, matrix method and modified moment distribution method etc. has been described.