Strength of concrete beams reinforced and/or prestressed with FRP bars

Non-corrosive Fiber Reinforced Polymers (FRP) are becoming a desirable replacement to steel bars in reinforcing/prestressing concrete structures. However, the difference between the two materials is not only related to the properties in the longitudinal direction of bars as most of the current research work and design guidelines are concerned with. The properties in the transverse direction of the bars have basic differences which may influence the beam strength and its mode of failure. This paper presents a comprehensive analytical modeling to evaluate the strength of concrete beams reinforced and/or prestressed with FRP bars and the corresponding mode of failure including the pre-mature failure of beam due to the dowel failure of FRP reinforcement. The model takes into account significant parameters such as the crack path geometry, the crack width, and the properties of FRP bars in both longitudinal and transverse directions. Also, the contribution of stirrups, if any, is obtained based on the actual number and tensile strain of the stirrups crossing the failure crack. A good agreement has been observed between the results of the developed modeling and the corresponding experimental results.