The load-displacement characteristics of corroded reinforced concrete members as revealed by structural experiments and finite element analysis

초록

It is essential to investigate the effects of corrosion-damaged reinforced concrete (R/C) members on the overall seismic performance of structures. It then becomes possible to assess more accurately the seismic safety of R/C buildings that include corroded components such as beams and columns. However, the existing guidelines for seismic evaluation of R/C structures-such as FEMA 310 and the Standard for Seismic Evaluation of Existing Reinforced Concrete Buildings by the Japan Building Disaster Prevention Association-do not consider deterioration, including rebar corrosion, when assessing seismic performance. Although previous experimental and analytical studies on corroded R/C members reported quantitative reductions in the load-carrying capacity, few studies have investigated hysteretic characteristics related to member strength and deformability or used finite element analysis incorporating bond degradation caused by rebar corrosion. In short, the seismic performance of R/C structures with corrosion-damaged members should be quantitatively and directly evaluated by reference to any reduction in performance based on the strength-deformation capacity as reflected in the hysteresis characteristics. To assess the seismic capacity of corroded R/C structures, it is essential to analyze the strength-deformation behavior of damaged members across the cracking, yielding, and final performance stages. This study investigated the effects of corrosion on the restoring force of RC flexural and shear beams. Following electrochemical accelerated corrosion and monotonic loading tests, a finite element model was developed using a bond stress-slip relationship to simulate bond strength loss. The model was validated against experimental data and used to predict the behavior of beams with corrosion levels not covered in the physical tests. Strength-deformation characteristics were then analyzed across the cracking, yielding, and ultimate performance stages.

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