Earthquake Response of Base-Isolated Liquid Storage Tanks for Different Isolator Models

Abstract

The effect of different isolator parameters on earthquake response of base-isolated liquid storage tanks is investigated herein. Mechanical analog, with three lumped masses, is used to model ground supported base-isolated liquid storage tank, and analyzed for recorded earthquake ground accelerations. The nonlinear force-deformation behavior of the isolator is mathematically modeled in two different ways, represented by (a) equivalent linear elastic-viscous and (b) bi-linear hysteretic behaviors. The equations of motion for the base-isolated tank are derived and solved in the incremental form using Newmark's step-by-step method of integration. Two different configurations of liquid storage tank (i.e. broad and slender) are considered to show the effect of the equivalent linear and bi-linear modeling of the isolator on the important earthquake response quantities. Effect of nonlinear hysteretic modeling of the isolator on peak response of the baseisolated liquid storage tanks is also investigated. The effect on earthquake response of the base-isolated liquid storage tank is studied for different parameters of the isolator for a range of slenderness ratio of the tank. The parameters considered include the characteristic strength of the isolator, isolation time period, isolator yield displacement etc. Significant difference is observed in the earthquake response of the base-isolated liquid storage tanks owing to the equivalent linear and bi-linear modeling approaches of the isolator. However, for bi-linear and nonlinear hysteretic modeling of the isolator, difference between the peak earthquake response of base-isolated liquid storage tanks are insignificant. The earthquake response of base-isolated liquid storage tanks is significantly influenced by the variation in the isolator parameters and slenderness ratio of the tank

Performance of RC elevated liquid storage tanks installed with semi‐active pseudo‐negative stiffness dampers

“…This is a peculiarity of the elevated liquid storage tanks; as the mass of the liquid is significantly high as compared to the mass of the structure, the time period is governed by the tank‐filled condition. The fundamental natural time period is higher for the lower aspect ratio ( S = 0.5), which agrees with the results obtained and reported by Saha et al 10 In the case of the broad tank ( S = 0.5), most of the mass of the liquid takes part in the convective mode leading to a longer time period. However, for the slender tank ( S = 2.0), less mass of the liquid participates in the convective mode (Mode 1), exciting higher frequencies in the structure and consequently reducing the natural time period of the structure.…”

“…[1][2][3][4][5][6] Several researchers have effectively used the base-isolation technique for seismic response reduction of ground-supported liquid storage tanks. [7][8][9][10] The use of passive control technologies such as base isolation and friction dampers for elevated liquid storage tanks was studied by Shenton and Hampton, 11 Shrimali and Jangid, 12,13 and Swanson et al 14 Further, the response of shaft-supported tanks was studied by Moslemi et al 15 Semi-active control strategies in pseudo-negative stiffness (PNS) dampers 16 and magnetorheological (MR) damper 17 have been used for ground-supported liquid storage tanks.…”

Evaluation of linear visco-elastic model of quintuple friction pendulum isolator

“…where F + and Fare the maximum positive and negative forces at displacement D + and D -, respectively (Matsagar and Jangid, 2004;Saha et al, 2014;Ghodke and Jangid, 2016).…”

Response and damage evaluation of base-isolated concrete liquid storage tank under seismic excitations

“…The reduction of the shear forces and overturning moments were assessed due to the friction pendulum isolator (FPS). Saha et al [21] investigated the various parameters that alter the responses for a base-isolated LST. The impact of the isolator's time period and yield displacement was varied to determine the LST optimum response reduction.…”