Abstract: On the basis of the fundamental assumptions for the planar steel structureswith semi-rigid connections and the typical stiffness equations of the framed element,the generalized elastic computational model of the planar steelstructures, of which the arbitrary connection stiffness can be assumed at the endsof each element, is put forward with mathematical derivations.With the parameters associated with the semi-rigid connections considered in thismodel taking special values, the model can easily degenerate into two of theidealizations: fully rigid and pinned. The model presented here canalso be used in a static analysis of general structures with semi-rigid connections and mixedconnections.