Static and fatigue analyses of RC beams strengthened with CFRP laminates

Extensive testing has shown that externally bonded carbon fiber reinforced polymer (CFRP) laminates are particularly suited for improving the short-te rm behavior of deficient reinforced concrete beams. Accelerated fatigue tes ts conducted to date confirm that fatigue response is also improved. This p aper describes an analytical model for simulating the static response and a ccelerated fatigue behavior of reinforced concrete beams strengthened with CFRP laminates. Static and fatigue calculations are carried out using a fib er section model that accounts for the nonlinear time-dependent behavior of concrete, steel yielding, and rupture of CFRP laminates. Analysis results are compared with experimental data from two sets of accelerated fatigue te sts on CFRP strengthened beams and show good agreement. Cyclic fatigue caus es a time-dependent redistribution of stresses, which leads to a mild incre ase in steel and CFRP laminate stresses as fatigue life is exhausted. Based on the findings, design considerations are suggested for the repair and/or strengthening of reinforced concrete beams using CFRP laminates.