Evaluating the Behavior of Welding-Defected CFRP Fiber-Reinforced Double-Channel Steel Columns

In recent years, engineers have faced many structural problems, such as buckling, corrosion and excessive loading in damaged steel structures. The labor force's mistakes during welding and the destruction of the weld are among the many problems in steel structures. Therefore, strengthening and repairing the welding place in steel structures is inevitable. In this article, the influence of polymers reinforced with carbon fibers for strengthening steel studded double columns with defects caused by welding has been investigated. For this purpose, seven steel columns were modelled in Abaqus finite element software. A CONTROL column was modelled as the first sample with no defects and welded all over. The rest of the defective samples were reinforced using CFRP fibers. On the other hand, strengthening using CFRP fibres to improve the location of the defect was investigated in detail for three samples. Reinforcement of these sections using CFRP fibers is not only an effective method to increase the maximum axial force in these columns, but it has also helped to improve resistance and delay local buckling in them. According to the results, it was observed that among all the samples, the maximum bearing capacity is related to the 2UW3 model, and it has increased by 29.9% and 21.7% in the laboratory sample and numerical modelling, respectively, compared to the 2UW3C1 sample. In addition, 2UW3C1 and 2UW1C1 samples have the highest hardness among laboratory and numerical modelling samples, respectively.