Flexural Response of Corroded Reinforced Concrete Beams Strengthened with Powder-Actuated Fastened Composites

This paper examines the effect of corrosion exposure on the flexural response of reinforced concrete (RC) beams strengthened with a powder-actuated fastened (PAF) composite system. Twenty-one RC beams were constructed and tested to failure under four-point bending. The corroded beams were subjected to 30, 60, and 100 days of accelerated corrosion that corresponded to measured tensile steel mass losses of 6, 11, and 18%, respectively. Other test parameters included width of the fiber-reinforced polymer (FRP) composite strip, fastener length, and number of fastener rows. For the undamaged beams, the PAF-FRP system resulted in up to 24% increase in flexural capacity and 20% average reduction in beam ductility. The strengthening effectiveness reduced with increased level of corrosion damage. Nevertheless, the flexural strength of the strengthened specimens at all levels of corrosion was either higher or almost same as that of the control specimen. Increasing the fastener length increased the gain in flexural capacity of the undamaged beams but had no noticeable effect on the flexural strength gain of the corroded beams. Doubling the width of the FRP strip or number of fastener rows had insignificant effect on the flexural strength gain. An analytical model that can predict the flexural capacity of corroded RC beams strengthened with a PAF-FRP system has been introduced. The model accounts for the nonlinear behavior of materials and strain incompatibility between the PAF-FRP strip and concrete. The validity of the model has been demonstrated by comparing its predictions with the experimental results. (C) 2013 American Society of Civil Engineers.