COMPARING THE PERFORMANCES OF FRAMED BUILDINGS EQUIPPED WITH DIFFERENT DAMPERS CONFIGURATIONS

The present work presents a design procedure to compare the effectiveness of different viscous dampers placement in framed structures, in terms of system cost and effectiveness. The analytical procedure is developed from the selection of a specific deformed shape for the first vibration mode of the system, to evaluate the corresponding period of vibration and damping ratio through an equivalent single degree of freedom system. Once a target damping ratio and the corresponding desired reduction in the frame seismic response is assigned, the structure peak response registered under specific earthquake levels can be evaluated. From these parameters, the total cost expressed in terms of maximum required damper forces and its effectiveness expressed as the ratio of the total cost and the benefit (i.e. base shear reduction) are evaluated for each configuration of dampers. The procedure is finally specified for the case of linear along the height peak displacement profile for three specific dampers configuration: (i) inter-storey placement, referred to as stiffness proportional damping SPD; (ii) fixed point placement, referred to as mass proportional damping MPD; (iii) dissipative tower DT. The actual seismic behaviors of the designed structures are verified through non-linear time-history analyses.