Elastic Lateral Buckling of Stepped I-Beams

The elastic flexural-torsional buckling of simply supported stepped I-beams under a central concentrated load is examined theoretically and experimentally. The effects of the magnitude and position of steps on a beam's sectional properties are studied, and theoretical elastic critical load parameters are tabulated. Experimental studies are described and the results, which confirm the theoretical findings, are presented. A simple approximate method of predicting the elastic critical loads is proposed which appears to be either of close accuracy or conservative. The tabulated values and the approxmation should be of use in the design of laterally unsupported stepped I-beams.