OPTIMAL PLACEMENT of MULTIPLE TUNED MASS DAMPERS to IMPROVE STRUCTURAL PERFORMANCE of BUILDINGS UNDER EARTHQUAKE EXCITATION
Recent earthquakes show that buildings should be designed carefully to ensure satisfactory performance under earthquake loading. Efforts have been made to reduce damage to structures using various approaches. One of the devices used to reduce dynamic response of building is Multiple Tuned Mass Dampers (MTMD). Studies have shown that MTMD with an optimum combination of parameters (mass ratio, damping ratio, and frequency) has some advantages over single Tuned Mass Damper (TMD), especially for random loading. The analyses were mostly conducted for buildings with dominant first mode, thus placing all MTMD at the top floor gave satisfactory results. However, higher modes may have significant effects on building performance. Therefore, this study aims to better understand the optimal placement of MTMD for different structures to improve building performance under earthquake excitation. Numerical analyses were conducted and several structural models were developed with different first mode participation factors. Then, the optimal placement of MTMD was exercised to improve structural performance. The effectiveness of the proposed system was examined using recorded earthquake ground motions as inputs. The performance was measured in terms of percentage of reductions in critical response quantities. This study reveals that MTMD system can improve the structural performance especially in the case of mistuning and in the case where higher modes have significant effects. The results also show that with the effect of placement of MTMD system is insignificant in reducing structural responses.