Analysis of initially crooked, end restrained steel columns

Abstract

A new and general method of analysis for steel columns, which can simultaneously take into account the effects of initial crookedness, end restraint, residual stress and load eccentricity, has been developed. The method gives the complete load-deflection relationship of a column, including both the ascending and descending branches. Unlike most of the currently used methods, the basic required input is the stress-strain relationships of the material, instead of some pre-determined moment-thrust-curvature relationships for the cross sections. Application is first made to develop theoretical predictions for some selected columns which were tested using either the geometrical alignment or the load alignment procedure. It is shown that the latter tends to be stronger and gives a higher test load. The results of two parametric studies, which included such variables as magnitude of initial crookedness, amount of end restraint, pattern of residual stress distribution, and axis of bending, are also presented. Certain conclusions with regard to the relative importance of these variables are drawn.