Behaviour of RC beams strengthened with FRP laminates and tested under cyclic loading at low temperatures

Abstract

Fiber reinforced polymeric (FRP) laminates, which have been used in the aerospace industry for several decades, are becoming increasingly popular in the construction industry for strengthening purposes. Although the use of this strengthening technique is increasing rapidly, more data are needed in the area of bond and long-term durability before it can be fully accepted. The study described in this paper is part of a larger investigation on the use of carbon fiber reinforced polymeric (CFRP) sheets for repair and retrofit of reinforced concrete (RC) beams. The experimental program included tests in flexure and shear of strengthened beams under low temperature (–29°C) and high amplitude cyclic loading which are described in this paper. Four RC beams strengthened with FRP laminates were tested under low temperature conditions. Out of four, two beams were tested monotonically to failure and the other two were tested under high amplitude cyclic load (fatigue load). The amplitude of the cyclic fatigue load was taken as 10–80% of the failure load from the monotonic test. Test results suggest that the presence of the low temperature did not affect the behavior of the CFRP strengthening system itself, or the interface on the laminate side.