Basic Influence Line Equations for Continuous Beams and Rigid Frames

The subject matter of this paper is essentially an extension of the moment distribution method of analysis and with the aim of offering a simple approach to the construction of influence line diagrams for continuous structures, the members of which can be either of constant or of variable cross section. The distributions of the fixed-end moments are similar to the Hardy-Cross approach except that they are performed algebraically rather than by successive arithmetical approximations. The results are a series of simple equations with only one unknown, which can be easily evaluated with the aid of a desk calculator or by elementary programming for the computer. These simple equations can be expanded to include the effects of sway. They also include the effects of degrees of end fixation.