Axial behaviour of square HSS tubular members strengthening with CFRP sheets

Abstract

Hollow structural steel (HSS) tubular sections are increasingly popular now in many metallic structures for economic and effective standpoint, but they suffer severe fatigue crack and deterioration due to the severe environmental condition. Fibre reinforced polymers (FRP) can solve the above mentioned complications effectively. FRP composite materials on steel tubular structures are having very good attachment and exhibit similar property. Due to this merits, FRP-Steel combination increased in the construction industry in recent era. Current research work demonstrated the different forms of orientation and combination (transverse and longitudinal) of CFRP wrapping on HSS tubes under axial compression. In this experimental program, unidirectional CFRP sheets are used as a continuous sheets bonded to HSS specimens both transverse and longitudinal direction. Totally eighteen HSS tubes were used for axial compression testing. Among eighteen columns, sixteen columns were externally bonded by CFRP strips and the remaining two columns were unwrapped (Control). After the compression test, various aspects like effect of inclusion of transverse and longitudinal CFRP fabrics, load carrying capacity and stress strain characteristics were investigated. Experimental results also revealed that, addition of more transverse CFRP fabrics significantly increases the ultimate load and stress-strain capacity compared to that of longitudinal CFRP inclusion.