Experimental investigation on torsional behavior of CFRP strengthened square hollow steel section

This paper presented a study on the behavior of Carbon-fiber-reinforced- polymer (CFRP) strengthened steel beam specimens with square hollow section (SHS) under torsion. A set of tests on CFRP strengthened steel specimens under torsion was carried out in which several different strengthening configurations were used. CFRP sheet wrapping consisted of different configurations including vertical, spiral, and reverse-spiral wrapping were used. The results showed that using CFRP could improve the elastic and plastic torsional strength of CFRP strengthened steel beam specimens. The number of layers of CFRP and the strengthening configurations were important factors for the improvement. The failure modes and the amount of increase in the yield and ultimate torque for different strengthening configuration monitored and were presented in this paper. The results obtained can be useful in the design of the CFRP strengthened steel members under torsion.