Experimental study of the flexural response of steel beams strengthened with anchored hybrid composites

This paper proposes an innovative technique for flexural strengthening of steel beams using a special type of drillable fiber reinforced polymer laminates. The utilized laminates are hybrid carbon-glass fiber (CFRP-GRFP) pultruded strips that provide both high tensile and high bearing strengths. The current study explores experimentally the potential enhancement in the flexural capacity of steel beams strengthened with mechanically anchored CFRP-GFRP laminates. The experimental program involves flexural testing of eleven full-scale beams under three-point loading. The influence of various strengthening parameters including length and thickness of FRP laminates, and number of anchoring bolts on the behavior is investigated. The experimental results reveal that increasing length and/or thickness of the FRP laminates improves the ultimate capacity of the strengthened sections. Strengthened beams are shown to exhibit ductile response associated with high deflection if adequate number of anchors is used. Otherwise, a brittle failure takes place because of shear failure in the anchors connecting FRP laminates to the steel beam.