The effect of tuned liquid damper placement on the seismic response of a high-rise building: A reduced-order modelling study

High-fidelity fluid–structure interaction (FSI) analysis is widely recognized as one of the most accurate approaches for evaluating the seismic performance of tuned liquid dampers (TLDs). However, coupling a three-dimensional FSI model with a detailed finite-element model of a high-rise building requires substantial computational resources, limiting its application in routine engineering analysis and preliminary design. This study develops and validates a computationally efficient reduced-order structural–FSI framework that preserves the dominant structural dynamic characteristics while explicitly modeling three-dimensional liquid sloshing. A 30-story reinforced-concrete building is first modeled in ETABS to extract its modal properties. The detailed structural model is subsequently transformed into an equivalent lumped mass–spring–damper system implemented in ANSYS and coupled with three-dimensional TLD fluid domains using FLUID80 elements. The reduced-order structural model reproduces the fundamental natural frequency of the full three-dimensional model with an error of less than 0.2%, demonstrating excellent agreement in the dominant dynamic response. Nonlinear time-history analyses are performed under the 1940 El Centro north–south earthquake record to investigate two practical TLD layouts: six tanks installed at the roof and a distributed configuration with three tanks at the roof and three at mid-height. Both configurations reduce global structural displacement and generally mitigate interstory drift and story shear, although local increases in drift or shear can occur at some floors. The roof-mounted configuration decreases the peak roof displacement from 0.389 m to 0.352 m (approximately 9.5%) and reduces the maximum base shear from 5.52 x 107 N to 5.22 x 107 N. Although the distributed configuration provides smaller global reductions, it offers improved response mitigation at intermediate stories through enhanced interaction with higher vibration modes. The proposed framework provides a mechanically consistent and computationally practical methodology for system-level seismic assessment and preliminary design of high-rise buildings incorporating tuned liquid dampers.