Analysis of Frames with Partial Connection Rigidity

A computer oriented method is described for the analysis of frames with partially rigid beam-to-column connections. The moment-rotation relationship for the partially rigid connections is approximated by a bilinear model. Slopes of these models are graphically determined and used to define connection rigidities. Element stiffness matrices are derived which include the effect of these partial rigidities. The modified element stiffness matrices are then used in a direct stiffness method of solution. Analysis for stability of frames with partial connection rigidity is carried out using the classical method of determining bifurcation states. The modified element stiffness matrices incorporating the effects of partial connection rigidities are directly used in the analysis. Problems ranging from rigid frames to pin connected frames can be solved by the same appproach and examples are presented to show the results.