Efficacy of fluid viscous damper placement strategies on the seismic response of an irregular high-rise composite building

This study presents a comprehensive numerical investigation into the structural performance enhancement of an irregular, high-rise steel-concrete composite building through the strategic implementation of nonlinear fluid viscous dampers (FVDs). The imperative for advanced seismic protection systems has been underscored by recent devastating earthquakes, which revealed the vulnerabilities of conventional structural designs. In this context, FVDs offer a compelling solution for passive energy dissipation. A high-fidelity, three-dimensional finite element model of a 20-story composite structure, characterized by geometric irregularities and vertical stiffness transitions, was developed. The research methodology involves a comparative analysis between a Conventional Structural System (CSS) and seven distinct Enhanced Structural System (ESS) variants, each incorporating FVDs in different placement configurations. Using nonlinear time-history analysis with a ground motion record from the 2023 Kahramanmaraş, Türkiye earthquake, matched to the design spectrum per TBDY-2018, key performance indicators were assessed. The findings indicate that all FVD configurations produce significant performance gains. Comprehensive damper installations yielded the most substantial improvements, reducing peak story displacements and interstory drifts by up to 55% and lowering base shear by nearly 50%. Furthermore, the analysis revealed that targeted placement in critical zones of stiffness discontinuity offers a highly efficient alternative, achieving considerable benefits with a fraction of the devices. This research demonstrates that the efficacy of FVDs is critically linked to their placement strategy and provides a performance-based framework for optimizing their integration into complex, irregular composite structures, contributing to the design of safer and more resilient high-rise buildings.