Anchorage of reinforced concrete parapets on glass fiber reinforced polymer bridge decks: Fid-Bau Portal

Anchorage of reinforced concrete parapets on glass fiber reinforced polymer bridge decks

Naito, Clay

A research program was conducted on reinforced concrete parapets mounted on self-supporting FRP bridge deck systems. This paper discusses the test series performed and details effective methods of connecting a conventional reinforced concrete parapet and glass FRP bridge deck. The deck system is a GFRP (glass fiber reinforced polymer) cell core structural system that provides web stiffness in two orthogonal directions. Pairs of uncoated reinforcing bars embedded in the deck are coupled to the epoxy coated reinforcement in the RC (reinforced concrete) parapet by a cast threaded splice. The embedded bars are placed at the seam of the transverse and horizontal webs. Anchorage of reinforced concrete parapets in conventional FRP bridge decks using embedded straight bars, is not attainable due to the shallow deck thickness and the occurrence of tension in the FRP deck perpendicular to the axis of the anchorage bars. This significantly reduces the available bond strength provided by mechanical interlock and results in pullout of the tensile reinforcement from the deck. In addition, transfer of lateral loads relies on a shear friction mechanism between the RC parapet and FRP deck. This produces local crushing of the top deck flange. To eliminate these mechanisms headed reinforcing bars can be anchored in the bottom flange of the deck to reduce pullout and FRP wafers can be used locally in the top deck flange to increase shear friction resistance. These details allow for the development of the full strength of the parapet without damage to the supporting bridge deck and are recommended for future constructions.