Experimental and numerical investigation on torsion strength of light gauge SHS strengthened with CFRP wraps

Abstract

In this research, an experimental and numerical investigation on the influence of strengthening steel square hollow sections (SHS) subjected to pure torsion with Carbon Fiber Reinforced Polymers (CFRP) wraps. CFRP was widely used to strengthen steel members in bending and compression. Experimental tests were conducted on 8 light-gauged steel SHS having two different cross-sections, SHS 48×2 mm, SHS 80×2 mm. Four strengthening configurations were tested; namely, Spiral, Reverse, Spiral-Reverse, and Reverse-Spiral. All specimens were wrapped with an orientation angle 45° with respect to the longitudinal axes of the specimen. Results showed that Spiral-Reverse and Reverse-Spiral configurations offered higher capacity enhancement. Strengthened specimens with these configurations reached up to 96% increase in their torsional capacity with respect to the control bare specimen. Spiral and Reverse configurations showed lower torsional capacity enhancement with a maximum percentage of 47%. Finite element models were constructed to simulate the tested specimens. The general purpose finite element program ANSYS was used to establish a numerical model for strengthened SHS incorporating geometric and material non-linearity. The numerical solution was essentially non-linear static analysis at which the load was applied incrementally using the arc-length method. The limit load of strengthened SHS was defined by the load at which the total strain energy reached 1.2 times that of respective bare SHS as per experimental results obtained herein. The proposed numerical model provided compatible results with test results obtained herein and previous literature.