3D finite element analysis of deficient hollow steel beams strengthened using cfrp composite under torsional load

In recent years, strengthening of steel square hollow sections (SHS) using carbon fiber reinforced polymer (CFRP) has attracted the attention of many researchers. Most of the previous research in this field has been done on the behavior of steel members without deficiency in bending, shear, and compression strengthened using CFRP composite. Few studies have been conducted on steel torsional beams strengthened using CFRP, and to the author's knowledge, no research on the behavior of CFRP strengthened deficient hollow steel beams under torsional load has been presented. The deficiency in steel beams may be created due to the errors caused by construction, fatigue cracking, drilling after building for passing building installation, corrosion, earthquake damage, and so on. However, this study explored the effect of the use of adhesively bonded CFRP flexible sheets on the structural behavior of SHS steel torsional beams having initial deficiencies, using finite element investigation. To study the effects of the CFRP strengthening method on recovering the strength lost in the deficient beams, twelve hollow steel beams with different deficiencies that were strengthened using CFRP sheets, four nonstrengthened hollow steel beams with different deficiencies, and one nonstrengthened hollow steel beams without deficiency as a control column were analyzed. To analyze the beams, three-dimensional (3D) modeling and nonlinear static analysis methods using ANSYS software were applied. The results indicated that application of CFRP sheets for strengthening of deficient torsional hollow steel beams could recover the strength lost due to deficiency, significantly. © 2017 by Begell House, Inc.