Experimental Research On Seismic Performance Of Corroded RC Frame Joints In Artificial Simulated Acid Rain Environment

With the rapid development of industrial construction, air pollution is more and more serious, acid rain pollution has become one of the most serious pollution problem in modern society. Existing buildings are affected by acid rain corrosion in a certain extent, acid rain can result serious chemical corrosion of reinforced concrete structure and influence the durability of the concrete structure to make the mechanical properties degradation. It is necessary to consider the damage to the durability of concrete structure in acid rain environment for accurately assess the seismic performance of existing buildings, and it provides the basis for accurate analysis of urban multi-age building vulnerability.This paper designs 6 reinforced concrete joints, put them into the artificial climate chamber and corrode them in different degrees by acid rain by artificial simulated acid rain, aimed to study the effects of seismic performance in different corrosion degree in different ratio of axial compression of corroded joints. Although the research on seismic performance of reinforced concrete joints have made a lot of achievements by the scholars in the world, but they do not consider the effect of acid rain environment long-term corrosion on the seismic performance to the joints. In this paper, through the pseudo static test,get hysteretic curves, skeleton curves, stiffness(strength) degradation curve and energy dissipation degradation curves of corroded joints,in order to research the degradation law on seismic performance of corroded joints.Through the pseudo static seismic test of corroded joints, the study shows: in the acid environment, in the acid environment, the seismic performance of reinforced concrete joints have been seriously affected, the seismic performance indicators are decreased with the deepening of the de gree of corrosion of corroded joints strength、stiffness、ductility and energy dissipation capacity. The axial compression ratio of corroded specimens similar effect on the intact specimens, all with the decrease of axial compression ratio of the bearing capacity decreases, the ductility increased. Based on the test results,shear stress and shear deformation in different states of the joint core zone has been obtained by calculation,and get Corrosion depth of corroded joints by material tests,thus fit the relationship curves with the corrosion depth and axial compression ratio of the cracking、the peak shear stress and shear deformation of the joint core zone.Based on threefold skeleton curves model, calculate the characteristic parameters value of the skeleton curve of corroded joint, by introducing the damage model and the reduced coefficient based on deformation and energy and considering the pinch effect, strength degradation, stiffness degradation of joint, to establish the restoring force model of corroded joints. And comparison the calculate hysteretic curve of corroded joint with experimental curve, the restoring force model of corroded joint has good applicability. Finally, based on the existing joint model of Open Sees, to finite element analysis was carried out based on the corrosion of seismic test, And compared with the experimental values are in good agreement with the experimental curves.