Assessment of stresses and vibration behavior of concrete gravity dam under fluctuating hydrostatic force

Abstract

Dam structure contributes to the socio-economic development of a country but zero probability of failure of such structure is a design concern. Hence, it is essential to monitor the dam condition under the fluctuating reservoir water and the vibration effect. In this investigation, four different cases of the reservoir depths are adopted to numerically analyze the hydrostatic and modal (free-vibration) behavior of a three-dimensional (3D) gravity dam. The impact of fluctuating reservoir water and uplift pressure on the dam's internal stresses (direct, principal, shear, and Von Mises) are evaluated to examine the location of maximum stress concentration. Under these cases, the maximum displacement along the longitudinal and vertical directions is explored. It can be revealed that case 4 (without tail-water) induces the maximum displacement on the top crest level and the peak normal stress concentrated at the heel region, respectively. This case also experienced the lowest time-period and largest frequency. In comparison to cases 2, 3, and 4, case 1 exhibit the largest crest level displacements along the x-direction that are 26%, 49%, and 86% higher, respectively. Compared to case 1, the normal stresses along the x-direction declined by 51.58%, 68.74%, and 58.25%, respectively for cases 2, 3, and 4. It can be revealed that the frequency is directly related, while the time-period is inversely proportional to the mode-shapes. Overall, this study envisages a comprehensive understanding of the dam’s performance, providing critical data to inform design decisions, safety assessments, and performance improvements.