Flexural Experiment And Theoretical Research Of RC Beam Under The Chloride Coupled With Long-term Load

The durability of concrete structures is an issue of common concern to the engineering field, where steel corrosion has become one of the most important factors which affecting the durability of concrete structure, while overloading operators in the actual presence of the bridge, and caused a negligible impact on the bridge structure. So study the influence of loading and chloride ion complex effect on mechanical properties of RC beams is particularly important.Paper uses the experimental and theoretical methods to studies influence of loading effect on the rate of corrosion of reinforced concrete beams, and on this basis, the calculating model of flexural rigidity and capacity of corroded reinforced concrete beams which considering the impact of loading is given, following respects are mainly included in the research:1) First, flexural capacity experimental studied made on reinforced concrete beams which without been chloride penetrated. Based on the flexural deflection of specifications to define the boundaries between the nomoal state and overloading state. On this base, an external direct current technique was used to accelerate the corrosion of reinforcement, testing of corroded reinforced concrete beams in normal state and two overloading levels. The results indicate that overloading has a significant effect on corrosion, the corrosion rate is accelerated under overloading. With overloading the time dependent deflection of the beams increase and the residual loading capacity decrease. The reinforced concrete structure are usually subjected to overloading.2) The relationship between different states across the load and deflection, and the factor which influence the rigidity of reinforced concrete beams are analyzed. Then the strain coordinating relationship between the steel and concrete is established. Though fitting for the rate of steel corrosion, found out the quantitative relationship between sustained load level and the rate of steel corrosion. On this base, the calculation model of flexural rigidity of reinforced concrete beams with corroded bars is established.3) The depth of corrosion of steel for data acquisition, by fitting the experimental data to identify the relationship between load and steel section loss rate, then estabilish calculation model of flexural capacity of reinforced concrete beams with corroded bars. By comparison with experimental data to validate the calculation model.The results showed that the formula established in this paper has high computation precision. The research can offer reference to the durability design of reinforced concrete structures.