Time-Dependent Deformation of a Concrete Arch Dam in Thailand - Numerical Study on Effect of Alkali Silica Reaction on Deflection of Arch

Abstract

A detailed inspection of a dam in Thailand is reported for its time-dependent gradual expansion towards upstream, contrary to the expected downstream creep deflection owing to hydrostatic loads. In this study, based on petrographic analysis and SEM, a sample of cored concrete from the dam was found to undergo a low to moderate level of ASR. The potential for future expansion was verified using an accelerated laboratory test. The experimental data were used to evaluate the dam performance by conducting an FEM analysis. The numerical model was calibrated with the observed deflection, and the mechanical stresses owing to the combined ASR and hydrostatic loads were estimated for various ages of the dam. In addition, stress and deflection were predicted using probabilistic methods. A sensitivity analysis was also performed to monitor the behaviour of the dam under various environmental conditions and input parameters. It was found that the gradual deterioration by ASR does not pose a high risk to the dam under normal loading conditions.

Study on the freeze–thaw effect on concrete arch dam using an improved response surface method

“…Pan et al proposed a unified approach for long-term behavior and seismic response analysis of AAR (alkali-aggregate reaction) -affected concrete dams by combining AAR kinetics, effects of creep and plastic-damage model in the finite element method 13 . Joshi et al studied the effect of alkali silica reaction on the deflection of an arch dam 14 . The currently proposed degradation models did not take into account many uncertain factors, such as external load uncertainty, structural mechanical uncertainty and so on.…”