Low cost maglev guideway design using hybrid FRP-reinforced concrete

Successful implementation of maglev technology in the U.S. depends greatly on a low cost guideway system. Additional performance related guideway structural requirements such as durability for a fifty year lifespan and magnetic inertness of structural materials in certain areas also must be considered. Fiber reinforced plastic, FRP, material - a thermosetting resin material typically reinforced by either glass or carbon fibers (though other synthetic and natural fibers are possible) - is non-magnetic, non-corrosive, and potentially can serve as tensile reinforcement in concrete guideways. Though glass fiber reinforced plastic, GFRP, is relatively inexpensive and has high strength characteristics, it suffers in at least three respects: 1) low stiffness, 2) brittle failure, and 3) deterioration over time in concrete due to the alkaline environment of the concrete. Carbon fiber reinforced plastic, CFRP, has high strength and stiffness and is inert to the concrete alkaline environment. However, CFRP is considered expensive and also fails in a brittle manner. This paper presents a design approach for producing a `hybrid' FRP rod having glass fibers integrated with carbon fibers in such a way that glass fibers are insulated from the outside environment (i.e. from the concrete) by both carbon fibers and an epoxy matrix. Such a hybrid FRP rod can be low cost, durable in concrete, and engineered to fail in a pseudo-ductile manner. This paper will 1) discuss the need for cost effective maglev guideway design and describe methods to obtain low cost structural elements, 2) provide a background of candidate FRP materials, and 3) present a design approach for engineering a hybrid FRP rod suitable for use in concrete.