Research On The Reinforcementeffect Of Injury Beams Of The Unloading Degree

Nowadays RC (reinforced concrete) is the widest application in the field of construction. The RC flexural members take full advantage of rebar's high tensile strength & concrete's high compression strength. During designed lifetime, due to improper design, improper construction, misuse, degradation of materials, earthquakes, fire & etc, the RC structure will be damaged to the extent of the difference, with the building existing safety potential. Currently, in most of study on reinforcing the RC beam, the members are reinforced in tests and then analyzed under the condition that the member is not damaged or completely unloaded after damage. However, the studies under imitating actual loading are seldom found.In this test, nine RC beams are made with the same dimension. One of them is not reinforced for reference, and others are loaded to designated load and then unloaded to different grades. Keeping the load unchanged, the RC beams are fortified with external reinforcement with steel plates & carbon fiber. Do the static test on the reference beam and tested ones, and then study the effect of bending resistance & unloading degree of reinforced RC beams on reinforcing the damaged RC beams with different loads after the same damage load.The research results show: compared to the reference beam, the bearing capacity of the reinforced beams is greatly improved. While the capacities of the beams reinforced with steel plates are almost the same, the effect by level of unloading on the ultimate bearing capacity of reinforced beams is no greatly different, but much different to the beams reinforced by carbon fiber. The ultimate bearing capacity is gradually reduced as the increase of the loading. The reinforcement with steel is more effective under the high load. The rigidity of the beams reinforced with steel is improved a bit, but almost the same on the condition of different level of loading when reinforced. For the beams reinforced with carbon fiber, the rigidity and the use ratio of carbon fiber is reduced as the increase of loading during reinforcement.