Interactive instabilities of thin-walled laminated composite pultrusion box columns

The problem of interactive buckling and post-buckling of intermediate length thin-walled columns built of laminated plate elements subjected to compressive load has been proposed and solved analytically. Pultrusion columns have wide-range applications in high-rise building due to their low weight and high load carrying capacity. Classic stability theory and laminate theory were implemented to prove the existence of mixed-mode buckling in thin-walled pultrusion columns. Interactive stability modes can result in lower loading capacity of most compressive members and affects their post-buckling behaviour in major proportions. Interactive buckling load analysis has been performed by means of a simplified theoretical model and verified by means of numerical analysis. The calculations were carried out for commonly used square section thin-walled composite columns dimensions. The post-buckling performance of selected sections has been investigated and an optimum layup configuration criterion for each section has been extracted according to pre- and post-critical behaviour. Copyright (c) 2010 John Wiley & Sons, Ltd.