Lateral-Torsional buckling of end-restrained beams

Abstract The influence of semi-rigid joint action on the behaviour and strength of laterally unsupported beams has been investigated using a finite element approach. The ultimate strength analysis allows for the effects of initial deflections, residual stresses and the gradual development of yielded zones. Connection behaviour is modelled with a multi-linear representation of in-plane moment-rotation (M-φ) behaviour. The validity of the program has been verified by checking against both analytical and experimental results. A parametric study has been conducted to assess both the importance of end-restraint effects and the sensitivity of the beam's strength to variations in the main problem variables. Studies of the spread of yield have been employed to explain the various phenomena observed. The results have been used as the basis for an assessment of the methods used to allow for end restraint in the new UK steelwork code.