Strength of beam-columns in flexibly connected steel frames
This thesis describes an experimental study undertaken to examine the influence of joint resistance to in-plane moments on the performance of steel columns and complete frames. The principal objective of the tests was to provide experimental data against Which sophisticated computer analysis programs may be verified. Details of the experimental study of 22 joint tests, eight column subassemblages, and two three storey, two bay steel frames are reported. It is demonstrated that all beam to column connections have an inherent degree of stiffness and that their moment-rotation characteristics are non-linear. The load carrying capacity of columns, confined to buckle in-plane, is shown to be enhanced considerably by the resistance to rotation provided by simple beam to column connections. In frames incorporating flange cleat connections the beams and columns can sustain greater loading and deflect less than is predicted by current design models. The assumptions of pin-ended columns and simply supported beams are shown to be conservative. Comparisons of the results of the column and frame tests with two finite element analysis programs are presented. The use of computer programs for semi-rigid design as well as the development of a simple approach are discussed.