Split frame method for lateral load analysis of short frames

For preliminary design of tall frames, information regarding stress resultants due to lateral loads is required even before member dimensions are known. For this purpose, the portal and cantilever methods are sought in practice for the specific reason that they do not require cross sectional dimensions for the analysis. The conceptual power of these two methods is such that the solution is accepted without demur by the practicing engineers. This paper delineates yet another procedure which throws more light on the evolution process for determining the shear force in the columns of the storey under consideration. The modified analysis propounded gives almost the same answer as that of the improved portal method. The reasoned supposition put forward for the determination of shear is lucid, efficacious, powerful and realistic. The method does not entail much computational effort and redounds to arriving at acceptable terminal moments in beams and columns of the plane frame.