The problem of creep failure of composite columns subjected to a compressive load has been considered. The failure is associated with allowable stresses and the corresponding allowable deformations. The approach can be used to establish tolerances for initial imperfections of viscoelastic columns based on a predicted longevity. Another approach can predict an allowable duration of the action of the load based on predicted (or allowable) initial imperfections. Numerical examples illustrate that the allowable duration of loading is drastically reduced due to either large initial imperfections or significant applied compressive stresses. As could be expected, an increase of the allowable stresses and a decrease of the column length have beneficial effects on the allowable duration of loading. © 1994.