Behaviour of hybrid FRP composite I-girder with concrete deck

Abstract

The behavior of hybrid Fiber Reinforced Polymer (FRP) I-girder with compositely acting concrete deck is discussed in this paper. The innovative feature of this hybrid composite girder optimizes the combined use of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) in flanges to maximize structural performance while reducing the overall cost by using only GFRP in the web section. Preliminary investigations revealed that the hybrid FRP girder failed due to local buckling, separation of laminates and crushing near the loading point in the compression flange with the compressive and tensile strain smaller than the expected maximum strains. In view of improving its structural performance, concrete deck was provided on top of hybrid FRP composite girder to give stability on the thin compression flange because of its high compressive strength. Two types of shear connections were trialed to provide composite action between the hybrid FRP girder and concrete deck. Results of the experiment showed that a good composite action was achieved between hybrid FRP girder and concrete deck using steel u-bolts combined with epoxy for shear connection. The composite action leads to a higher tensile strain in the hybrid FRP girder and resulted to efficient utilization of the FRP materials. The results of the Fibre Model Analysis using the effective mechanical properties of the hybrid FRP showed a good agreement with the experimental data