Experimental Study Under Cyclic Loading On Durably Damaged Reinforced Concrete Column Joint

With the long-term use, there appears durable damage in reinforced concrete structures, including concrete carbonization and corrosion of reinforcement, which would lead to a significant reduction in the seismic performance (bearing capacity, stiffness, ductility and hysteretic behavior) of structures. Relying on the National Natural Science Foundation "Seismic durability research of reinforced concrete structures", the paper studies the influence of concrete carbonization and corrosion of reinforcement on the column-joint seismic performance by the test under cyclic Loading. The main work o is as follows:①A test under low cyclic loading is conducted in11durably damaged reinforced concrete column joints. The results prove that the specimen model, parameter design, test unit and test methods are successful.②Studying the influence rule of longitudinal reinforcement corrosion rate on the column-joint seismic performance by the test. The results show that:with the increase of longitudinal reinforcement corrosion rate, the column nodes have bending failure, bearing capacity and stiffness reduce, ductility and hysteretic energy dissipation become worse.③Studying the influence rule of stirrup corrosion rate on the column-joint seismic performance by the test. The results show that:with the increase of stirrup corrosion rate, the column-node failure patterns transforms from bending failure to shear failure, have bending failure, bearing capacity and stiffness reduce, ductility and hysteretic energy dissipation become worse.④Studying the influence rule of concrete carbonization and stirrup corrosion on the column-joint seismic performance by the test. The results show that:with the constancy of carbonation depth and the increase of stirrup corrosion rate, the column-node failure patterns transform from bending failure to shear failure,have bending failure, bearing capacity and stiffness reduce, ductility and hysteretic energy dissipation become worse. With the constancy of stirrup corrosion rate, carbonization can improve the bearing capacity and stiffness,reduce ductility and have little effcet on hysteretic energy dissipation.