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Reliability Risk-Based Analysis and Mitigation Measures of Existing Concrete Gravity Dam |
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PP: 1381-1399 |
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doi:10.18576/amis/180617
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Author(s) |
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Zakaria Che Muda,
Mohamed Hafez,
Lariyah Mohd Sidek,
Salmia Beddu,
Payam Shafigh,
Zaher Almkahar,
As’ad Zakaria,
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Abstract |
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| The paper investigates the suitability of using FORM and Monte Carlo reliability risk analysis for mitigation measures of the existing concrete gravity dam. Many aging gravity dams need rehabilitation resulting from dam safety assessment based on the current stringent safety standards due to climate change. The sliding failure mode is the dominant mode failure over the overturning where its mitigation measures are required for remedial works of the existing dam. Sensitivity analysis of friction angle has the highest sensitivity of 91.2% compared with 8.6% for the density of concrete and cohesion with only 0.2%. The mitigation measure using post-tensioned anchors and raked micro-piles for the probability of sliding failure mode was investigated using the Monte Carlo simulation. There is only a marginal increase in post-tensioning design force and no changes to the micro-pile if the probability of failure needs to be decreased from 10-4 to no likelihood of failure under each event scenario. It is prudent to look into these measures as there is no implication on the construction cost and the time for completion. Raked micro-piles provide a better remedial option than post-tensioned anchors as they do not intrude into the main body of the structure nor interrupt the operation of the hydropower plant. Reliability risk analysis using Monte Carlo simulation is a powerful tool that can be utilized in the assessment and mitigation measures of the existing dam.
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