Innovative Design of FRP Combined with Concrete: Short-Term Behavior

TLDR

The study proposes a new GFRP‑concrete‑CFRP box‑beam design that combines a concrete layer in compression with a CFRP laminate in tension, offering a pultrusion‑based manufacturing route for simply supported spans. Analytical predictions were validated through large‑scale bending tests and finite‑element simulations, and a preliminary design procedure incorporating stiffness, strength, and ductility criteria was developed. The hybrid members exhibit cost‑effective, pseudoductile behavior with high stiffness and strength, and experimental results closely matched the analytical predictions.

Abstract

The study presents the mechanics associated with the short-term behavior of glass-fiber reinforced-plastic (GFRP) box beams that include a layer of concrete and a carbon-fiber–reinforced-plastic laminate (CFRP) in the compression and the tension zone, respectively. This innovative concept results in cost-effective composite members with pseudoductile characteristics and high stiffness and strength properties. It can be thought of as a better way of producing composite structural members for simply supported spans, through an automated manufacturing technique such as pultrusion. The analytical results are verified by a series of bending tests on large-scale specimens and by the finite-element technique. The agreement between experiments and analysis was found quite satisfactory. A preliminary design procedure for the hybrid members is also presented, based on a complete set of stiffness, strength (flexural strength, web shear failure by either crushing or buckling, lateral instability), and ductility design requirements.