Analysis Of Hysteresis Performance Of The Corroded Reinforced Concrete Columns And Beams

There will appear an phenomenon of material degradation,such as corrosion forreinforced and carbonation for concrete so on, in the process of long-term use forreinforced concrete structures, leading to degradation of structural performance, andmaking the structure do not work ahead of time. Under the action of the earthquake,the concrete structures of deterioration are more vulnerable to damage of earthquake.Reinforced concrete column and beam is the main bearing component for reinforcedconcrete frame structure, which the size of aseismic capacity determines seismicperformance of the frame structure. Hysteresis curve is an very important index inthe seismic energy dissipation capacity of reinforced concrete structure or component.Therefore, the study of hysteresis curve’s energy-dissipating capacity for the corrodedreinforced concrete structures or components, having important theoreticalsignificance and engineering practical value, which can provide theoretical basis forthe seismic strengthening of the active structure.In this paper, we adopted the method of the theoretical analysis and numericalsimulation in order to study hysteretic performance of the reinforced concretemembers of deterioration, which the specific work is as follows：(1)Consulting literature of the domestic and abroad on the experimental researchof the corrosion for the material of reinforced concrete, Summarizing the mechanicalproperties of corroded reinforcent and the carbonizing concrete, determing theconstitutive relation of corroded reinforcent and the carbonizing concrete andconstitutive relation of the bond-slip between reinforcent and concrete, which aredetermed in the numerical simulation, selecting concrete damage plasticity model,which have more reasonable parameters, the unit of concrete, steel bar element andthe type of nonlinear spring element.(2)On the basis of above work, we adopt ABAQUS to establish the finiteelement model of the corrosion reinforced concrete column. rebar corrosion ratemodel of the reinforced concrete column. When the simulation, we consider theinfluence of the level of different longitudinal reinforcement corrosion and concrete carbonization. By numerical simulation, we can get the load-displacement curveunder the monotonic load, hysteresis curve under cyclic loading. According to thehysteretic curve which is obtained by calculation, we can extract the skeleton curve,stiffness degradation and energy dissipation curve. Analysis shows that the differenceof the hysteresis curve for column, which have different degree of reinforcementcorrosion and different axial compression ratio, is significant. With the increase of thedegree of reinforcement corrosion, the bearing capacity and stiffness of pillars isreduced, and hysteretic curve gradually turn a bow-shaped into an s-shaped, the areaof hysteresis loop become smaller, the "pinch approach" phenomenon is more serious,which shows that the performance of seismic energy dissipation of pillars becomeweak. For the component which have the same rebar corrosion rate, bearing capacityof the pillar whose axial compression ratio is0.27bearing capacity is bigger thanpillars whose axial compression ratio is0.2, which suggest that axial compressionratio of having certain limits is conducive to improve the bearing capacity ofcomponents, energy dissipation and rigidity, while with the increase of corrosion rate,the performance of all aspects of column is decline. after concrete carbonation,bearing capacity of components have certain extent increase, but the stiffness ofcomponents decreased quickly and ductility of components reduced, the componentpresent a large brittleness, which is against for resistance to earthquake.(3)Similar to the analysis process of pillars, this article has also establishedfinite element model of a cantilever beam for corroded reinforced concrete, andobtained the hysteretic curve and skeleton curve of different component of corrosiondegree. The results show that the degradation performance of corrosion beam andcolumn is consistent, but they have certain difference, and the most obviousdifference is that under the action of repeated loading, deformation of beams andcolumns, axial compression of column make damage of concrete toward the bottomof core concrete development, when the concrete cracking. The expansion of bottomof column is more obvious, while the destruction of the beam are near the support,but mesh stretching is more serious, and inflation is not obvious.