OPTIMUM EXPANSION RATIO OF CASTELLATED STEEL BEAMS

Abstract

Abstract In this paper, the authors present a numerical analysis for the optimum expansion ratio based on the elastic as well as the plastic method of analysis. The elastic analysis program is based on an iterative process and involves the calculation of allowable loads corresponding to potentially critical flexural and shear stresses at each increment of the expansion ratio. The plastic analysis program considers three types of collapse mechanisms: (1) Vierendeel mechanism, which is caused by the formation of plastic hinges at the four reentrant corners; (2) Flexural mechanism, which occurs when the flanges of the critical panels become completely plastified; and (3) Failure caused by the yielding and rupture of a welded joint. An experimental program involving the testing of five beams expanded to different depths has confirmed the theoretical predictions.