Abstract: Experiments were conducted to investigate the flexural behaviors of eight simply-supported RC beams strengthened with carbon fiber sheets,steel stands,prestressed steel stands,and steel plate individually and two comparative beams.Base on the experimental results,the flexural properties,failure characteristics,and the effect of different rehabilitation methods are analyzed.The cracking load,yielding load,ultimate load,ductility,development of cracks,deflection and rigidity are discussed.Experimental results show that 1) Compared with un-strengthened beams,the cracking load of RC beams strengthened with four different methods mentioned above are improved by 27.8%,59.7%,94.4% and 73.6%,respectively;yielding load are improved by 12.4%,26.1%,36.2% and 37.6%,respectively;ultimate load are improved by 23.6%,21.0%,31.1% and 19.6%,respectively;and ultimate deflection declines by 23.6%,21.0%,31.1% and 19.6%,respectively.2) From the angle of the normal use,the strengthening effect of beams strengthened with prestressed steel stands is better than that of un-prestressed.3) Steel stand can effectively improve the post-yielding stiffness of strengthened beams,while that of steel plate is not very effective.