Analysis of Concrete Bridge Girders Strengthened with Frp Laminates under Service and Extreme Loading Conditions

The project is a continuation from fiscal year 2004-2005. Previous work aimed at developing new analytical tools for analysis of RC beams strengthened with FRP laminates. The models were used to analyze several test specimens of RC beams and to investigate the corresponding failure mode, and whether it is due to CFRP fracture, debonding, or concrete crushing. Current work focused on using the existing model to conduct a thorough analytical evaluation of current ACI-440 design specifications for RC beams strengthened with CFRP laminates. Based on these studies, a new equation for the limitation set on the strength of FRP sheets in order to prevent debonding failure has been proposed. In addition, the model has been expanded to simulate the behavior of concrete girders reinforced with FRP bars. In this case, analytical studies have been performed in order to conduct an evaluation of current ACI-440 design equations for development lengths. The effect of different parameters such as concrete strength, confinement, FRP strength, and bar diameter has been investigated and a new equation for development lengths is currently being proposed for monotonic loading conditions. Currently, the study is also focusing on evaluation of design specifications under cyclic loading conditions, typical of seismic excitations.