Seismic response control of tall building using semi-active tuned mass damper considering soil-structure interaction

Abstract

Soil-structure interaction (SSI) will change structural characteristics of a tall building, while parameters of the passive tuned mass damper (TMD) should be specifically optimized in this case. However, the structural model and soil parameters are full of uncertainties, and the seismic response mitigation of passive TMD suffers from the frequency and damping detuning. To improve its seismic performance, the semi-active TMD (STMD) is presented in this study, which can adjust frequency and damping ratio simultaneously. It can not only add or remove its mass to retune the frequency, but the eddy current damping ratio can also be adjusted in real time by reset the air gap, according to a developed output signals based solely combined algorithm. To verify its seismic mitigation performance preliminarily, a SDOF main structure is investigated, while it is found that when the frequency detuning occurs on the STMD with variable damping solely, a significant performance degradation is detected; while STMD with variable frequency and damping ratio always has the best control performance. Then, a 40-story benchmark high-rise building with different SSI types is presented as the case study. Numerical results show that STMD can reduce structural displacement responses effectively and has a better control performance than optimal passive TMD for each model. Meanwhile, frequency detuning of passive TMD is discussed and degradation of robustness is found in the passive TMD with ±15 % stiffness detuning. It can be known that proposed STMD has the best control robustness as well, because it is always tuned.