Mechanical fatigue response of fiber-reinforced polymeric (FRP) composites is essential to better understand the durability of composite materials systems and to develop design specifications. Currently, the fatigue response of multidirectional glass composite materials is not well-understood and much needs to be done to understand their behavior under fatigue loading. In this study, three glass fabric FRP composite material coupons and systems are tested at constant lowamplitude fatigue loading. Experimental results show that for a given FRP material and load configuration, the energy loss per cycle due to fatigue damage is linear from about 10-90% of the fatigue life of the FRP composite material. The energy loss per cycle is determined to be a characteristic value of the constituent materials, and is found to vary with the induced fatigue strain levels by a power law. Based on the experimental results, a fatigue life prediction model is proposed, with internal strain energy as damage metric, to predict the useful life of FRP composites. The experimental and predicted fatigue lives at various strain levels are compared (S-N curves) and the model is found to be conservative.

Fiber-reinforced polymer (FRP) composites have been used more often over the past decade than before in new construction as well as in repair of deteriorated bridges. Many of these bridges are on low-volume roads, where they receive very little attention. It is imperative that new bridge construction or repair be long lasting, nearly maintenance free, and as economical as possible. Relative to those factors, FRP composite bridges have been found to be structurally adequate and feasible because of their reduced maintenance cost and limited environmental impact (i.e., no harmful chemicals leaching into the atmosphere with longer service life). In West Virginia, 23 FRP composite bridges have been constructed, among which 18 are built on low-volume roads that have an average daily traffic (ADT) of less than 1,000, including 7 with ADT less than 400. General FRP composite bridge geometry and preliminary field responses are presented as are some of the preliminary construction specifications and cost data of FRP composite bridges built on low-volume roads in West Virginia

Fiber-reinforced polymer (FRP) composite materials have shown great potential as alternative bridge construction materials to conventional materials such as steel and concrete. This is especially valid in the field of repair and rehabilitation of existing bridges as well as in new bridge construction. The acceptance of composites in the highway bridge industry is mainly due to their superior properties such as high strength, durability, corrosion resistance, and fatigue resistance. Moreover, FRPs are well suited for mass production of structural shapes because of their high strength-to-weight ratios, which has resulted in the rapid installation of FRP modular decks on highway bridges. Details related to the construction of FRP modular decks as replacements on existing highway bridge superstructures are provided. In addition, details on shipping, handling, erection, assembly, deck-to-deck connections, deck-to-stringer connections, joints, and wearing surfaces are discussed.

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