Research On Seismic Performance Of Reinforced Concrete Frame Effected By Reinforcement Corrosion

Reinforced concrete material has been widely used in the world, including used in constructions, bridges, marine engineering etc. The mechanical properties of RC material were deteriorated due to the environmental attacks among the service life of construction and bridges, then the security and applicability of structures were decreased. Among the frequent environment attacks of concrete, the loss caused by reinforced corrosion was a major part. So to monitoring the degree of reinforcement corrosion was particular important. Otherwise, the available research on evaluating the effects of reinforcement corrosion on the dynamic properties of RC was most carried on numerical simulations and component tests. The experimental research on structures was insufficient. As result of above discussion, this paper was focus on following contents by the way of combing experiments and simulations.Firstly, the accelerated corrosion experiment and electrochemical monitoring of reinforcement corrosion degrees were carried out. The four RC frames and two RC columns were cast and then accelerated reinforcement corrosion was carried by applying continues current. According to Faraday law, the degree of reinforcement corrosion of RC frames and columns was controlled by current density and time. After finished the accelerated corrosion experiment, the electrochemical monitoring was carried on RC columns. Three monitoring methods including Half–Potential method, Gecor6 and Five Electrode method were used and the experimental results show that three method are feasible, and further, the Five Electrode method is more stable and believable. The three methods can be used in couple in the practical engineering.Secondly, the mechanical experimental research and mode analysis experimental research were respectively carried on columns and frames effected by reinforcement corrosion. In addition, the time history analysis of frames was carried out by the way of numerical simulation. According to the experiment of pull-out tests, it was shown that the bond stress between steel and concrete was increased by expansion of rust when the corrosion rate was at 10%, and was decreased by spalling due to continual expansion of rust when the corrosion rate was at 30%. The tensile tests show that the reinforcement corrosion has little effect on the yield strength of steel and has significant effect on ultimate strength of steel. The strain-stress relations of steel were determined by above experiments, and then the constitutive relation was used in FEM model, at last, the time history analysis was done for the numerical model.Finally, the comparative analysis between a new built four-story structure and the same structure at the end of service life suffering reinforcement corrosion was carried out by finite element method. The effect of carbonation on the mechanical properties of reinforcement concrete was studied, including compressive strength, cross-section of steel, yield strength, elongation etc. and then the dynamic elastic-plastic analysis was done for the four-story building on the base of above analysis.