Collapse Loads of Laced Columns

The imperfection sensitivity of laced columns is investigated, the imperfection consisting of both a local and an overall geometrical imperfections. A simple numerical method is given and used for solving the linear elastic as well as the linear elastic-ideally plastic problem. The collapse load in the latter case is approximated with the load, initiating yielding in the structure. It is shown that the linear-elastic column, after reaching the collapse load, behaves almost like a shell and must, therefore, be expected to be sensitive to imperfections. It is shown that the relative drop in capacity of the linear elastic-ideal plastic column is largest when the two critical Euler stresses and the yield stress all coincide.