A novel scheme for the mitigation of the seismic action through the use of viscous dampers: minimal system analysis

This paper presents the results of an extensive (analytical and numerical) study carried out to investigate the effectiveness, for the mitigation of the seismic effects, of placing viscous dampers so that they connect the corresponding storeys of adjacent structural systems. These structures may be either two adjacent shear frame buildings or two portions of the same building (i.e. the frame structure and a stiff lateral resisting element external or internal to the structure). In this paper an analytical approach is carried out with reference to a basic system composed of two adjacent SDOF systems linked by a single damper is developed in order to understand the physical properties which govern the problem in question. The innovative arrangement substantially differs from the usual interstorey damper placement and leads to a clear indication for a new and efficient conceptual design for structures to be built in seismic areas. This peculiar damper arrangement for inserting added viscous dampers in shear-type structures, if damper sizing is chosen appropriately, may be traced back to the indirect implementation of the so-called MPD (mass proportional damping) system which has been extensively studied in previous research works by the authors and has proved to be characterised by superior dissipative properties.