2022 Fiscal Year Annual Research 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 / Spatial corrosion cracks / Structural performance / Maintenance and repair / Finite element analysis / Current density / Galvanostatic corrosion |
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| Outline of Annual Research Achievements |
It is important to study spatial steel corrosion and crack widths for predicting the deterioration levels and long-term structural performance of RC structures for maintenance action plan. In the experiment, effect of corrosion methods, galvanostatic (GS) and artificial chloride environment (ACE) methods, on the steel corrosion and corrosion cracks of RC beams were studied at different corrosion levels using X-ray and digital image processing techniques. For GS method, current density lower than 50 micro amperes per square centimeter is recommended to study steel corrosion since it produces the results close to that of ACE method. However, the crack widths generated by GS method are substantially smaller than those of ACE method. Considering this discrepancy, a correction factor shall be used to modify the crack widths of GS method when predicting the structural deterioration levels. In establishing finite element analysis to predict long-term structural performance, it is important to consider correlation of steel corrosion in both longitudinal and transverse directions when modeling spatial steel corrosion. 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 (unsafe) of yield loading capacities. Although FE method could well estimate the loading capacity of RC beams, it need to be more refined to accurately estimate the reduced ductility due to rebar rupture.
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