Bearing Capacity Evaluation And Numerical Simulation Analysis Of Strengthening Reinforced Concrete Beam

There is always the initial defects and material ageing in the bridge structure, under the load and the outside world long-term effects, these initial defects in the structure and the natural aging of the structure will enable the structure on the continuous development of injury and the structurefunction degradation, which may lead to structure in a certain period of use will become a dangerous bridge and facing damage, the danger of collapse. Therefore, the disease appeared on the structure should be detected, repair and reinforcement. In China, insufficient research exists on the fine reinforcement design, special reinforcement in the theory and construction methods of the design calculations. The strengthening design of some bridge mechanically apply the new bridge design, ignoring the impact of the strengthened bridge in service in phases to the mechanical characteristics and structural damage; individual bridges reinforcement designed with the macro-qualitative analysis, without scientific quantitative analysis, and with a large arbitrariness.This paper relys on the load test of the old bridge located in Ethiopia before and after reinforcement, analyzes the mechanism of the beam before and after bonded steel plates reinforced concrete beams with different affect, analyzes the reinforcement mechanism of an bridge in Ethiopia through finite element analysis software, studys the method to simulate reinforced concrete beams with cracks and the connection of steel plate and concrete, introduces Solid65element in ANSYS to simulate actual reinforced concrete structure. Sophisticated numerical experiment is used in the simulation of the bridge to study the flexural capacity, deflection, plastic deformation capacity and cracking behavior of reinforced concrete beams strengthened with steel plates. Combined with the analysis of the load test data of the bridge before and after reinforcement, with comparison of theoretical calculations and experimental results, the strengthening effect of the bridge is researched by quantitative analysis, and the cracking characteristics of strengthened bridge is also researched.The study of the Ethiopia project indicates that, the cause of the original bridge under dead load with a large deflection can be identified as deflection in construction phase, shrinkage and creep and material properties degradation, as well as its structural stiffness degradation, concrete cracking caused by corrosion, a higher degree of bridge damage accumulation caused by stiffness to continuously reduce with cracks ongoing. With the quantitative comparison before and after strengthening the bridge, it is found that the steel plates in bonding steel plates strengthened T beams of Ethiopian project makes a certain contribution to improve the beam stiffness, the plastic deformation capability of the T-beam has been improved to some extent after bonding steel plates, concrete and steel stress of the compressive zone did not change significantly, the stress of the tension zone changes a lot and the position of the neutral axis is lower than the old beam. It indicates that the steel plate play a certain amount role in bending resistance contribution of the strengthened beam. And it also shows that the suitable plate thickness should be used to avoid the compression failure of an over-reinforced member. In the project in Ethiopia, cracks in reinforced concrete in the main beam at different load cases significantly reduced. From the location of cracks in the beam direction and the bridge longitudinal direction, it shows that the strengthening measures of bonded steel can effectively control the further develop of the cracks and improve the bearing capacity of the bridge. The research on the special bridge of this paper can make a certain contribution to the design, construction and testing of strengthening this type of bridge, and pointed out the areas to be further studied.