Finite Element Investigation on the Effect of FRP Strengthening on Capacity of Steel Square HSS Columns

In this research, numerical finite element analysis was carried out to study the behavior of steel square HSS columns. The study focused on the effectiveness of reinforcing column sections with CFRP. A 3D FE model was developed using shell elements to represent the square HSS section. Extra layers of shell elements were added to the model to incorporate CFRP strengthening. Material and geometric nonlinearities were taken into account, and composite damage modeling was adopted for CFRP. The developed FE models were utilized to replicate experimental studies conducted by earlier researchers. Numerical analysis and previous experimental findings have shown to be in good agreement, establishing the validity and reliability of the current FE modeling scheme. Further parametric studies were conducted on non-compact AISC square HSS columns to observe the impact of CFRP layer count and cross-sectional shape on the increase of strength. Results indicated that increasing the number of FRP layers enhances column capacity. Further, the study showed that the medium and smaller HSS sections benefit more from CFRP retrofitting than the larger sections. The research in the paper offers a cost-effective way to understand CFRP-reinforced HSS sections. It can help with implementing CFRP retrofitting for steel HSS columns.