Background: Controlling lateral displacements and preventing collapse in high-rise structures has always been a major engineering challenge. This study was conducted with the aim of providing a comprehensive and comparative evaluation of the seismic behavior of such frames in two conditions: structures without dampers and structures equipped with viscous dampers. The significance of this research lies in offering a realistic understanding of the effectiveness of energy dissipation systems in improving the structural performance indices under severe earthquake excitations.
Methods: In this study, two three-dimensional steel structures with 12 and 16 stories and different geometric configurations were modeled in SAP2000-V19. All models were designed in accordance with the provisions of the fourth edition of Iranian Standard 2800 for a site located in a very high seismic hazard zone and classified as Soil Type III. To achieve an accurate assessment, a total of 16 structural models, including 8 models without dampers and 8 models equipped with viscous dampers, were subjected to nonlinear static (pushover) analysis and Incremental Dynamic Analysis (IDA). In the IDA procedure, the structures were evaluated under a set of scaled earthquake ground motion records up to the collapse threshold.
Results: The results indicated that geometric parameters have a significant influence on the seismic response. In particular, changes in column sections led to a meaningful increase in interstory drift and consequently intensified the structural vulnerability level. Moreover, increasing the number and length of spans in the Y direction improved the lateral stiffness and reduced the absolute lateral displacement of the structures. The key findings obtained from both IDA and pushover analyses were consistent and confirmed that the use of viscous dampers significantly reduces the dispersion of dynamic analysis results and enhances the energy dissipation capacity of the structures. The dampers were able to effectively mitigate both absolute and relative displacements at all earthquake intensity levels, from the serviceability state to collapse.
Conclusion: The conducted analyses clearly demonstrate that viscous dampers, by increasing the acceleration threshold that the structure can withstand, shift the capacity curves toward safer performance levels. These systems not only improve the structural stability against collapse, but also reduce post-earthquake repair costs by decreasing seismic demands. From an engineering application perspective, the simultaneous optimization of geometric section parameters and the use of viscous dampers is recommended as an efficient strategy for enhancing seismic resilience in high-rise steel buildings.