Effect of strengthening method and development length on flexural strength of rc beams with steel plates

The test result of an experimental study on the flexural strength of reinforced concrete beams strengthened with steel plates is presented. The beams were simply supported and loaded monotonically with two point loads. The test variables used in this study were strengthening method and development length of steel plates. Nine beams without strengthening and nine beams strengthened with steel plates were tested until the beams reach the flexural failure specified by crushing of concrete on the top surface of compression region. The test results show that steel plates increase the capacity of the beam significantly and slightly increase the flexural stiffness of the beams. In addition, the ultimate load of the strengthened beams with debonding failure was similar to the beams without strengthening if the load kept increasing until flexural failure. The test results also showed that the debonding failure occurred after the steel plate reach the yield stress value and the development length affects the failure mode of the strengthened beams. Analytical study based on a theoretical moment-curvature calculation of reinforced concrete cross-section was carried out in order to obtain the complete flexural response of the beams analytically. The comparison shows that analytical prediction provides good accuracy for both reinforced concrete beams with and without strengthenin