2021 Fiscal Year Research-status Report
Long-term structural performance assessment of corroded reinforced concrete structures using an integrated approach of probabilistic and finite element method
| Project/Area Number |
19K15078
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| Research Institution | Waseda University |
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Principal Investigator |
リム ソーポーケム 早稲田大学, 理工学術院, 講師(任期付) (60801305)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | Spatial steel corrosion / Finite element analysis / Galvanostatic method / Current density |
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| Outline of Annual Research Achievements |
The spatial steel weight loss of a corroded beam using galvanostatic method (GS) with a low current density of 10 micro amperes per square centimeter and two corroded beams using artificial chloride environment (ACE) method with wetting-drying cycle were obtained using X-ray and digital image processing techniques. The more comprehensive conclusion on the effect of current densities and corrosion methods on spatial steel corrosion and the structural performance of corroded beams can be drawn, as compared with the past experimental data. Using current density lower than 50 micro amperes per square centimeter causes localized pitting corrosions intensifying at a few locations over rebar which is similar to ACE method. However, using higher current density from 100 to 1000 micro amperes per square centimeter generates more uniform pattern of steel corrosion. The bending test results shows RC beams corroded with low current density and ACE method provided much lower ductility and loading capacity than those with high current density. Moreover, Monte-Carlo based finite element (FE) method is used to study the effect of corrosion methods on the distribution of loading capacities of RC beams at different corrosion levels. FE computational results show using statistic data of steel weight loss of corroded beams with low current density provides conservative estimation of yield loading capacities compared to those of ACE method. Using statistic data of corroded beams with high current densities provide overestimation of yield loading capacities.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The difficulties associated with pandemic situation diminish. Research facilities are open up for experiment team members to conduct the research. The corrosion process of a few remaining RC beams are in progress. The observation of steel corrosion in the RC beams using X-ray apparatus can be carried out.
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| Strategy for Future Research Activity |
The corrosion process and X-ray monitoring of a few remaining corroded RC beams is under the progress and planned to complete at the end of year. After the post-analysis of digital image processing for the spatial variability of steel weight loss and corrosion crack widths, the bending tests will be conducted to study the structural performance of the beams. Reliability of corroded RC beams using Monte-Carlo based finite element method will be conducted considering the effect of spatial steel corrosion.
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| Causes of Carryover |
Due to the difficult pandemic situations last year, the research activities were significantly hindered and A few planned conferences were canceled since the oversea travels were prohibited. For this year, the remaining amount of the fund will be utilized for the purchase of materials and tools for experiments, supporting fund for journal publications, and virtual conference attendances.
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