Efficiency and Robustness of Optimally Designed Tuned Mass Dampers for Mid- and High-Rise Buildings Under Far and Near-Field Earthquakes

Purpose The efficiency and robustness of tuned mass dampers (TMDs) are the two main criteria in the optimum design and evaluation of their seismic performance. In this study, a framework is presented for optimum seismic design and assessment of TMD performance in frequency and time domains based on efficiency and robustness. Material and methods Two 10- and 20-story linear shear buildings have been studied, which represent mid- and high-rise buildings, respectively, with two inherent damping ratios (2% and 5%) to evaluate the performance of TMDs in this framework. The TMD design has also been investigated for seven different mass ratios. The Particle Swarm Optimization method has been used to determine the optimal parameters of each damper, and the objective function is considered as minimizing the largest singular value of the inter-story drift transfer function to ensure the seismic performance and robustness of the TMD. In addition, three sets of seven earthquake records have been applied with different characteristics to evaluate the robustness of the TMD regarding the stochastic nature of the earthquake. Finally, to explicitly assess the robustness of optimally designed TMD with other uncertainties in the dynamic properties of the building and TMD, two sensitivity analyses have been performed in the frequency and time domain to achieve an unbiased seismic evaluation of optimally designed TMDs. Conclusion The results show the good performance of the damper with optimum parameters but its high sensitivity to the uncertainty of frequency ratio, especially in the time domain, can significantly reduce the seismic performance of the damper.