Through-thickness performance of adhesive joints between FRP bridge decks and steel girders

The through-thickness performance of adhesive joints between pultruded FRP bridge decks and steel girders was investigated experimentally and numerically. Through-thickness tensile stresses occur due to uplift forces caused by the load-bearing behavior of the bridge deck transverse to the bridge axis. The tensile stress distribution in the adhesive joint is non-uniform with high stress concentrations below the FRP webs of the cellular deck. The joint ultimate loads could be accurately predicted based on stress concentration factors from FEA and FRP through-thickness tensile strength values obtained from small-scale coupon tests. The total safety factor of the joint was higher than the safety factor of the FRP deck for bending between the main girders. Fatigue loading up to 10 million cycles showed no stiffness degradation.