Multi-objective stochastic optimization of tuned mass dampers under earthquake excitation considering soil-structure interaction

Tuned mass dampers (TMDs) are attractive vibration control devices, and their seismic attenuation depends on their frequency and damping coefficient. Structural characteristics are changed by the soil-structure interaction (SSI); therefore, SSI should be considered in the optimization of TMD. A high-rise building with 40 stories, including four different soil conditions, is proposed as a case study. For the objective function, considering the randomness of earthquakes, a stationary white noise stochastic process based on the Kanai-Tajimi spectrum was used as the input. To improve the performance of a TMD in controlling multimodal and overall dynamic responses, three objectives were considered in the objective function: the maximum and root mean square (RMS) displacements of the top story and the maximum displacement of all stories, respectively. The weight coefficient of each objective function was obtained according to the modal mass participation coefficient. To clearly observe the damping effect of the TMD with different parameter combinations, an ergodic parameter calculation is used. The TMD optimization parameters for each benchmark model with different soil conditions were proposed. Far-field ground motions were considered, and four optimized TMDs from reference were compared. The results show that the proposed TMDs can significantly mitigate earthquake oscillations in a great degree. They performed better than contrastively optimized TMDs under several earthquakes.