Experimental Investigation And Numerical Analysis Of Reinforced Concrete Beams Stiffened Using Aluminum Alloy

During the days of the rapid development of civil engineering , the aging of many old buildings has become a big problem that we are faced with. Because the existing old buildings can't meet new demands, we have to take some measures to deal with them, which are divided into two ways: (1)Remove old buildings and construct new ones to meet the demands;(2)Strengthen the old buildings. The first way is uneconomical, so the second way of strengthening existing buildings turns to be more advisable. Recent researches to the reinforcement of concrete structures at home and abroad mainly base on two materials: FRP and steel plates. However, either of the two materials has its limit: FRP is a kind of brittle material, which makes its destruction unexpected; steel plates rust easily. While aluminium alloy owns excellent ductility. What's more, there will be a layer of dense oxide film formed on its surface when exposed to the air, which gives it better erosion resistance. So it's necessary to research on the aluminium alloy strengthened concrete structures in the corrosive environment by the sea. The topic mainly researches on the bearing capacity, crack developments and failure modes of reinforced concrete beams after reinforcement with aluminium alloy structure.First of all, the article conducts mechanics performance tests to the aluminium alloy, rebars and concrete adopted in the aluminium alloy reinforcement beams, and also designs the three points bending test to the beams.Secondly, the article conducts three points bending test to the aluminium alloy beams of 6 different cross sections and two kinds of length(12 in total), according to the experiment control, the bearing capacity of reinforced concrete beams strengthened by aluminium alloy structure has improved obviously. The beams strengthened by plates break in two failure models: the peeling between substratum and aluminium alloy at the later cracks in the middle; the peeling between substratum and aluminium alloy plate at the shearing cracks in the end. The beams strengthed by aluminium alloy plate with stiffening ribs all break at the concrete cracks due to stress concentration at the end of the reinforced plate except L1300W90R1H20, which breaks because of the peeling in the middle. The reinforced concrete beams strengthened by aluminium alloy plates with stiffening ribs coordinate the peeling failures very well, but this test has not conducted sufficient shear-resisting reinforcement to the end of the beams, which makes the strength of aluminium alloy and the cementing strength of substratum have not been used sufficiently. The observed failure models in the test reveal that the break of reinforcement specimens due to stress concentration of the plate end still needs further research.At last, according to the behavioral parameters of the materials in the test, the subject adopts the abaqus software to simulate the test of aluminium alloy plates reinforced beams with stiffening ribs, and the simulating values and the testing values coordinate well. Also, the subject proposes some designing advice of reinforced beams of aluminium alloy plates according to the simulating results.