A study on effective rehabilitation method of shear buckling strength by CFRP in steel girder

To increase the shear strength of steel girders, several conventional methods and materials exist, such as bolting or welding of steel plates to the girder end area. However, recently Carbon Fiber Reinforced Polymer (CFRP) has been widely studied and used as an effective material for increasing the shear strength of the web plate in steel girder ends. However, the conventional approach of covering the entire web area with CFRP can be costly and excessively conservative. To efficiently increase shear buckling strength, this research aimed to determine the suitable area for CFRP coverage on the web plate along with the impact of CFRP application direction and the effect of attaching CFRP only to the web center. Through adopting an experimental approach, the study tested eight specimens, and the CFRP was applied in two distinct patterns to tension and compression directions. Furthermore, as for the CFRP coverage area, initially, the whole web area was covered with CFRP, and subsequently, the CFRP coverage area was parametrically reduced. The findings indicate that covering around 40% of the web area by CFRP can produce similar results as CFRP covering the whole web area. Additionally, it was found that the web and CFRP act as a unified composite section until the initiation of shear buckling, making the direction of CFRP application insignificant.