LRFD CRITERIA FOR STEEL BEAM-COLUMNS

An intensive investigation of the strength and behavior of steel beam-columns has been carried out with a view towards the development of load and resistance factor design (LRFD) criteria for such members. Since the solution for general beam-column is a very complex problem, thee first part of the paper gives an outline of the deterministic bases for the analysis of beam-columns, considering laterally supported and laterally unsupported members. Major attention is paid to the development of resistance factors for beam-columns, whereby the random nature of their strength is accounted for. Utilizing theoretical and experimental results, it is shown that a beam-column resistance factor of 0. 86 may be used for uniaxially loaded members. For biaxially loaded beam-columns the resistance factor may be set at the conservative figure of 0. 80, which reflects the scarcity of test results for such members. 18 refs.