Mechanical Behavior of Composite Sandwich Bridge Decks with Hybrid FRP-Steel Core

Design of bridge deck with long-term strength، durability and permanence is a significant interest for engineers. One applicable solution to this challenge could be via using hybrid system consisting of conventional materials such as concrete and steel with FRP plates which is also known as composite deck. Since these deck are relatively new so their performance is not completely known. The present study is dedicated to composite deck consists of a steel core and GFRP plates. This composite sandwich bridge deck system is composed of wrapped hybrid core of GFRP grid and multiple steel box cells with upper and lower GFRP facings. The structural performance of deck was evaluated by nonlinear finite element method and numerical results have been compared with available experimental results where possible. After ensuring the validity of numerical modeling of composite deck، parametric studies such as change in geometry، steel core shape and mechanical properties of materials have been done. It was found that failure mode of the proposed hybrid deck was more favorable because of the yielding of the steel tube when compared with that of absolute GFRP decks. Increasing the thickness and changing the steel core geometry can improve the ultimate load capacity of the deck. The grid layer has the maximum thickness among the GFRP layers and therefore ultimate load capacity of the deck enhanced by increase the elastic modulus of grid layer.