Strengthening of Continuous Beams Using Fiber Reinforced Polymer Laminates

Abstract

The use of fiber reinforced polymers (FRP) to strengthen sagging and hogging moment regions of continuous beams is discussed in this paper. Five two-span reinforced concrete beams with "T" cross sections were tested. Four different strengthening systems were examined. Two beams were strengthened with two different types of carbon fiber reinforced polymer (CFRP)sheets. The first beam was strengthened for flexure only while the second beam was strengthened for both flexure and shear. The third beam was strengthened for flexure only while the second beam was strengthened for both flexure and shear. The third beam was strengthened with glass fiber reinforced polymer (GFRP) sheets, while CFRP plates were used in strengthening the fourth beam. The fifth beam was a control. Each beam was loaded and unloaded for at least one cycle of loading before failure. The effects of FRP strengthening on failure modes, load capacity, cracking pattern and propagation, and deflections are presented. It was concluded that the use of FRP laminates to strengthen continuous beams is effective in reducing deflections and increasing their load carrying capacity. Furthermore, beams strengthened with FRP laminates exhibit smaller and better-distributed cracks.