Axial compressive strength of short steel and composite columns fabricated with high stength steel plate

Abstract

The design of tall buildings has recently provided many challenges to structural engineers.rnOne such challenge is to minimise the cross-sectional dimensions of columns to ensure greater floorrnspace in a building is attainable. This has both an economic and aesthetics benefit in buildings, whichrnrequire structural engineering solutions. The use of high strength steel in tall buildings has the ability tornachieve these benefits as the material provides a higher strength to cross-section ratio. However as thernstrength of the steel is increased the buckling characteristics become more dominant with slendernessrnlimits for both local and global buckling becoming more significant. To arrest the problems associatedrnwith buckling of high strength steel, concrete filling and encasement can be utilised as it has the affect ofrnchanging the buckling mode, which increases the strength and stiffness of the member. This paperrndescribes an experimental program undertaken for both encased and concrete filled composite columns,rnwhich were designed to be stocky in nature and thus fail by strength alone. The columns were designedrnto consider the strength in axial compression and were fabricated from high strength steel plate. Inrnaddition to the encased and concrete filled columns, unencased columns and hollow columns were alsornfabricated and tested to act as calibration specimens. A model for the axial strength was suggested andrnthis is shown to compare well with the test results. Finally aspects of further research are addressed inrnthis paper which include considering the effects of slender columns which may fail by globalrninstabilities.