Performance Evaluation of FRP Bridge Deck Under Shear Loads

Shear behavior of glass fiber reinforced polymer (FRP) bridge deck components has been experimentally and theoretically studied under in-plane shear, out-of-plane shear, punching shear, shear of web-flange junction, and system racking shear. Experimental data revealed that the shear modulus of FRP bridge decks ranged from 2.66 to 4.14 GPa and the shear stress to failure ranged from 20.7 to 96.6 MPa. In-plane shear behavior is studied under V-notched and racking shear test (parallel and perpendicular to cell direction). Experimental results under in-plane shear loading are compared with the results from the classical finite element method. Out-of-plane shear strength and stiffness of an FRP composite deck are experimentally evaluated utilizing test data from the short beam shear test, and the beam bending test. Using experimental and numerical results, the reduction in bending rigidity due to shear deformation under several loading conditions is calculated. In addition, size limits (span to depth ratio) under transverse loading are established as: L/d>422 (for multi-cell specimen with and without joints). A theoretical model based on FRP deck types for predicting punching shear capacity is proposed and validated through experimental data. In addition, the failure modes of test specimens are identified and reported. To study the web-flange junction behavior, closed FRP sections were tested under shear-bending effect. It is clear that the web-flange junction shear strength is only one half of the shear strength obtained from flange specimens under V-notched beam testing. While testing, cracks and layer delaminations around web-flange junctions were initiated and extended along the thickness of the web portion with increasing applied loads, which eventually led to web shear-off failure. In addition, it is found that shear strengths of test specimens depend on modes of shear failures induced by different shear test methods. Higher shear strength is found on failure modes that have more influence of fiber shear.