Research On Shear Capacity Of Simply Supported Concrete Beam With Corroded Reinforcement

The durability is one of the most noticeable problems of reinforced concrete structures in the world, and corroded reinforcement is an important factor to influence the durability of reinforced concrete structures. Because of the small stirrups diameter and the thin concrete protecting cover, stirrups' corrosion extent is always severe than longitudinal reinforcements'. The corrosion will result in the reduction of stirrups' section area, the rust expanding cracking of concrete protecting cover and the reduction of bond capacity between stirrups and concrete, and it will greatly reduce shear properties of reinforced concrete members. The decline of shear properties will result in brittle failure of diagonal section which brings more severe results to flexure failure.The shear properties of corroded reinforced concrete beam are analyzed and studied in this paper. Firstly, the harms, mechanisms and effect factors of corroded reinforcing steel bar are stated. Fourteen simple supported corroded reinforced concrete beams are tested. The test research of the test consider so many affecting factors as longitudinal steel's corrosion rate, stirrups' corrosion rate and shear-span rate. The crack process and failure model are observed. The datas such as deflection,longitudinal steel strain, stirrups strain and ultimate bear capacity are measured, and the test results are analyzed. The truss-arch model is adopted to deduce a theoretic formula calculating shear bear capacity of simple supported reinforced concrete beam with corroded stirrups and longitudinal steel. The formula preferably includes several factors effecting shear bear capacity of simple supported reinforced concrete beams with corroded stirrups and longitudinal steel such as shearing-span rate, stirrups rate, stirrups corrosion extent and longitudinal steel corrosion extent. The calculations are in good agreement with the tests. Furthermore, a practical simple calculating formula for shear capacity of simply supported concrete beams with corroded reinforcements is provided. The simple calculating formula is similar to the formula in the current concrete code, and it is safe and reasonable compared with the test results. In the end, some design advices are suggested on concrete beams with corroded reinforcements.