The most common technique of strengthening reinforced concrete beams without sufficient shear reinforcement is the use of exterior clamps around beams to provide additional shear reinforcement. Such clamps are generally arranged by engineering judgment, without any reliable analysis or a references. Although it is widely used in practice the effectiveness of this technique and its effects on the behavior and strength of the member have not been investigated. The aim of this study is to investigate experimentally the influence of exterior clamps on the behavior and strength of beams. In the experimental program four specimens (T-cross section) with shear span 3 have been tested. The test results have been evaluated so as to indicate the influence of this strengthening method on strength, rigidity and ductility of beams. Evaluation and interpretations showed that this strengthening technique is very effective. External clamps are provided so that while flexural behaviour was in progress at beam elements the shear cracks were successfully controlled.