Modeling the Structural Response of Steel Frames Equipped with Tuned Liquid Dampers under Seismic Excitation in OpenSees

Resumo

Tuned Liquid Dampers (TLDs) are passive structural vibration control devices whose efficiency and low cost make them a promising solution in civil engineering applications. Their implementation is particularly beneficial in slender or high-rise structures, in which dynamic loads—such as wind or seismic excitations—can compromise structural safety, the integrity of non-structural components, and occupant comfort. The operational principle is based on tuning the fundamental sloshing frequency of the liquid to match the natural frequency of the structure’s dominant mode, thereby generating inertial forces on the tank walls that counteract the structural motion.This study numerically evaluates the performance of a rooftop-mounted TLD in a steel Moment-Resisting Frame (MRF) using OpenSees. The analysis includes both harmonic resonant excitations and representative seismic records. The TLD is modeled using an Equivalent Mechanical Model (EMM) based on Housner’s analogy, which captures the liquid’s nonlinear behavior through a coupled mass-spring-damper system.Results indicate that the EMM provides accurate predictions of the TLD’s response under conditions of low excitation amplitude and high structural damping, achieving notable reductions in dynamic response. However, a progressive loss of efficiency is observed as the liquid’s depth-to-length ratio (h/L) increases, underscoring the importance of this parameter in TLD design.