Behavior of Deficient Steel Members Strengthened Using CFRP Under Combined Compressive Load and Torsional Moment

Strengthening steel structures using carbon fiber reinforced polymer (CFRP) has attracted the attention of many researchers in recent years. Most previous research in this area has carried out on the behavior of the steel members without deficiency in bending, shear, and compression. The deficiency in steel structures may be created due to the errors caused by construction, fatigue cracking, and so on. In addition, steel structures may be located under combined loads in their lifetime. This study explored the effect of CFRP strengthening on the structural behaviors of square hollow sections (SHS) steel members having initial deficiencies under combined compressive load and torsional moment. To the author’s knowledge, there is no independent article in this area. In this study, 17 specimens were analyzed. To analyze the specimens, three dimensional (3D) modeling and nonlinear static analysis using ANSYS software were applied. The results indicated that application of CFRP sheets for the strengthening of the deficient hollow steel members under combined compressive load and torsional moment could recover the strength lost due to deficiency, significantly. The maximum recovery percentage of the compressive load and torsional moment capacity of the specimens was 256.00% and 139.96%, respectively.