Performance of Reinforced Concrete Beams Strengthened with Mechanically-Fastened Composite System under Corrosive Environment
This study 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 fasteners rows. For the uncorroded beams, the PAF-FRP system resulted in up to 24% increase in beam flexural capacity and 20% average reduction in the beam ductility index. The strengthening effectiveness reduced with increased level of corrosion. Nevertheless, the flexural capacity of the strengthened beams at all levels of corrosion damage was either higher or almost same as that of the control beam. Increasing the fastener length increased the gain in flexural capacity of the uncorroded 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 PAF-FRP system has been introduced. The model accounts for the non-linear behavior of materials and strain incompatibility viii between the PAF-FRP strip and concrete. The validity of the analytical model has been demonstrated by comparing its predictions with the experimental results.