Blast mitigation of elevated water tanks equipped with resilient fluid viscous dampers

The dynamic behaviour of elevated water tanks in blast-prone ground vibration locations is a major concern due to threat from the increase in mining activities. The study aims to adopt passive control techniques in the form of fluid viscous damper to counteract these vibrations and mitigate the potential damage to water tank structures. The investigation incorporates finite element approach to simulate and analyse structural responses by employing a non-linear time history analysis to evaluate the performance of fluid viscous dampers (FVDs) under varying blast-induced ground motions. The study compares the effectiveness of the dampers by examining the liquid storage structures with and without damper conditions and quantifying the reductions in bending moments, shear forces, and displacements. Additionally, the study also compares the behaviour of the elevated tank for two conditions namely fully-filled and empty state for 50 m³ and 1500 m³ tank capacities with bracing systems, such as diagonal, X, V, Inverted V, and K bracing respectively subjected to underground blast induced vibrations. The study finds that the X-bracing pattern is the most effective configuration for FVDs in mitigating blast loads in a 50 m³ elevated tank without water, resulting in reductions of displacement, shear force, and bending moment by 75%, 50%, and 63% respectively, in case of elevated tank with water the structural responses reduced by 67%, 42%, and 58% respectively. In 1500 m³ elevated tank without water, the K-bracing is determined to be the most effective type of bracing pattern, reducing the displacement, shear force, and bending moment by 90%, 95%, and 95%, in case of elevated tank with water reduced by 80%, 80%, and 80% respectively. The results showcase the efficiency of fluid viscous dampers in absorbing and dissipating energy from blast-induced ground vibrations, safeguarding the structural integrity of elevated water tanks. Furthermore, the comparison between tanks with and without water provides insights into the influence of water presence on structural response, enabling informed decisions for optimal performance and safety.