Columns with Semirigid Joints

The influence of realistic semi-rigid end restraint on the strength and behaviour of real steel columns is investigated. An analytical procedure is developed which includes the effects of initial out-of-straightness, spread of yield and initial residual stresses. The procedure also permits the inclusion of the nonlinear restraining effect of the column's end connections as determined by tests on actual connections. Comparisons of initial results with available experimental data for end-restrained columns are made to verify the validity of the procedure. Agreement is shown to be acceptable. Load-deflection curves and column curves are produced for a series of column assemblies including both initially stress-free and residual stress conditions. Effective length factors calculated from these results indicate possible column design economies due to the actual end restraint present. The influence of end restraint on the distribution of internal stresses and hence the initiation of column yield is also discussed.