2019 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 – 2022-03-31
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| Keywords | Spatial steel corrosion / Finite element analysis / Monte Carlo simulation / Correlation of corrosion |
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| Outline of Annual Research Achievements |
The experimental and computational studies are performed to investigate the effects of correlated spatial corrosion of steel rebars in the transverse direction on the structural performance of reinforced concrete beams.In the experiment, three series of reinforced concrete beams (two specimens in each series) with three tensile rebars are corroded with the current density of 1000 micro amperes per square centimeter to obtain the targets of steel corrosion of 10%, 20%, and 30%. Experimental results indicated that the beams with higher correlation coefficients of steel weight loss between rebars (i.e. similar corrosion pattern of steel rebars in the transverse direction) exhibited lower load and deflection capacities than other beams with lower correlation coefficients. The flexural responses of the beams with multiple rebars simulated by the 3D finite element (FE) model were found to be in better agreement with the experimental results than those of the 2D FE model. A Monte Carlo simulation (MCS) was performed using a 3D FE model for two different cases: correlated and uncorrelated steel corrosion in the transverse direction of the RC beam. It was found that a stronger correlation of steel cross-sectional area loss on different tensile rebars led to a larger variation in the load capacities of the corroded RC beams.
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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
Although the present 3D finite element (FE) method can provide a good estimation of loading capacity of corroded RC beams, there is a need to refine the computational FE method to investigate the effect of correlated steel corrosion on the ductility of the RC beams in which a sudden failure mode of rebar rupture must be considered. More computational studies will be conducted and validated against the experimental results in terms of their ultimate deflections of corroded RC beams.
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| Strategy for Future Research Activity |
More experimental studies of steel corrosion from the corroded RC beams are needed to obtain more comprehensive findings and make generalized conclusions. Corrosion tests of other RC beams with lower current density and simulated wet-dry cycles are still in the progress and take a longer time to reach their target steel corrosion at the end of this year. According to the previous studies, experimental results of these specimens are, as expected, to be valuable and more accurate since their simulated steel corrosion was found to be similar to those of corroding RC structures under the natural conditions. After the corrosion test is completed, the bending test of the beams will be conducted, and more computational studies by 3D FE method will be conducted.
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| Causes of Carryover |
The conferences were postponed this year due to the pandemic. The remaining amount of money will be used next year for the conferences' registration, traveling, and accommodation fees.
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