Flange buckling behaviour of FRP box-beams: A parametric study

FRP is gaining popularity in civil engineering applications due to their high specific strength and stiffness, lightweight and tailoring ability. Meantime, box beam applications have also been increased in bridges due to their high inherent torsional stiffness. The combination of FRP and box-beam is ideal in lightweight bridges. However, being a thin-walled structure, designs are often governed by stability. In the FRP box-beam, two types of buckling are possible, i.e. flange and web buckling. In this paper, flange buckling behaviour of simply supported FRP box-beam subjected to lateral load has been studied with emphasis on the effect of moment gradient and rotational restraint. Web buckling is precluded by adopting thicker webs. Extensive numerical studies have been conducted to identify the parameters which significantly affect the flange buckling. The significance of defined parameters has been shown with the help of generic curves and bar charts, which will be helpful to the designers at the preliminary stage.