Investigation the Effects of Multiple Tuned Mass Damper on Reduction of Seismic Parameters of Tall Buildings Regular and Irregular on Plan in Steel Flexible Structures Under Near and Far-Fault Earthquakes

The tuned mass damper is one of the latest structural control system that helps the structure to damp the dynamics loads. So far using the Tuned Mass Damper (TMD) on the roof or a few dampers was installed at several points at the height of the building or other levels of the building was popular, but this system has some disadvantages like considering a significant mass as overhead which requires special material and enough space to install. Therefore, in this research the efficiency of Multiple Tuned Mass Damper (MTMD) in tall building is investigated. Also the effects of MTMD on regular and irregular tall moment resisting buildings are studied. The 10,15 and 20 story buildings with regular and irregular U and L shapes are modelled,analysed and designed, using the SAP 2000. Then the models equipped with MTMD and analysed in nonlinear dynamic mode under the earthquake records of the near and far fault , using OPENSEES. Afterwords, the models compared considering different earthquake records.finally the results showed the MTMD on the roof had seismic performance with 40% reduction of the base shear , 30% reduced absolute displacement of the stories and 35% smaller acceleration, which increased the efficiency of the models and the situation have improved their seismicity.