THE COMPOSITE RESPONSE ASSESSMENT OF THE STEEL BEAM-FRP DECK SYSTEM IN THE BOYER BRIDGE

Fiber Reinforced Polymer (FRP) composites have been considered as good alternatives for the repair and rehabilitation of damaged or deteriorating structures (e.g. highway bridges) recently. The present study reports on the field study of a steel beam-FRP deck composite bridge in Pennsylvania. The objective of the study is to assess the composite action between the steel beam-FRP deck system by evaluating the neutral axis location, the effective compression flange width and the distribution factors at service load conditions. The research results reported herein support the notion of employing a design approach, for both interior and exterior beams of a composite floor system, which is consistent with current practice related to steel beams acting compositely with concrete decking. It appears from the results presented herein that FRP decks and floors acting compositely with underlying steel beams exhibit an effective width approaching 75% of the actual beam spacing "s" for interior beams, and 90% of the total distance, made up of one half the value "s" added to the deck overhang for exterior beams. In addition, the live load distribution factors (DFs) obtained from the field tests show a very good agreement to the expected DFs for the case of steel beams with concrete decking