Optimal prestressing and configuration of stayed columns

A steel column that is reinforced by prestressed stays generally has an increased strength in axial compression. In the past, greater emphasis was placed on obtaining its higher critical buckling load. However, detailed knowledge of the post-buckling behaviour is important to ensure the safety and the efficiency of the structure. Although previous work revealed that the optimal design should be determined with the post-buckling response, the actual values of the optimal prestress had not been previously evaluated. The present work examines the issue of the true optimal prestress for stayed columns through proposed structural optimisation indicators involving both instability and material quantity measures. Non-linear finite-element analysis was performed to investigate the non-linear buckling behaviour, which gives values for these indicators. Through a comparison of these values, suggestions for the configurations for improving the structural efficiency are presented.