This paper provides illustrative examples regarding (a) the seismic performances offered by the MPD systems when applied to shear-type structures and (b) the implementation of MPD systems in actual building structures. As illustrated in a companion paper and in previous research works by the authors, the MPD system is an innovative system of added viscous dampers which is based upon the mass proportional damping component of Rayleigh viscous damping matrices and is characterized by a high dissipative efficiency. The seismic performances of two shear-type structures equipped with several systems of added viscous dampers (including, in addition to the MPD system, other optimal damping systems identified using genetic algorithms and inverse problem approach) are compared through numerical time-history simulations. The results, here obtained with reference to 40 historically recorded earthquake ground motions, confirm that systems characterized by dampers placed so that they connect each storey to a fixed point (as it is for the MPD system) display larger efficiency in energy dissipation than systems characterized by interstorey damper placement (traditional placement). The results also indicate that the forces exerted through the dampers of the MPD system and of the other damping systems considered are comparable in size. Two ways of implementing MPD systems in actual building structures are also presented: direct implementation (dampers connect each storey to the ground) and indirect implementation (dampers connect each storey of the base structure to a support structure: stiff vertical element, e.g. the conventional concrete core of the stairs/elevator typically found in r.c. constructions). Numerical results indicate that (provided that the support structure is characterized by a relatively large lateral stiffness) direct and indirect implementations lead to similar damping effect on the base structure without increasing the dynamic actions upon the support structure. Illustrative examples for the technical feasibility of both direct and indirect implementations are also provided.
Optimal Insertion of Viscous Dampers into Shear Type Structures: Seismic Performances and Applicability of the MPD System
SILVESTRI, STEFANO;TROMBETTI, TOMASO;CECCOLI, CLAUDIO
2004
Abstract
This paper provides illustrative examples regarding (a) the seismic performances offered by the MPD systems when applied to shear-type structures and (b) the implementation of MPD systems in actual building structures. As illustrated in a companion paper and in previous research works by the authors, the MPD system is an innovative system of added viscous dampers which is based upon the mass proportional damping component of Rayleigh viscous damping matrices and is characterized by a high dissipative efficiency. The seismic performances of two shear-type structures equipped with several systems of added viscous dampers (including, in addition to the MPD system, other optimal damping systems identified using genetic algorithms and inverse problem approach) are compared through numerical time-history simulations. The results, here obtained with reference to 40 historically recorded earthquake ground motions, confirm that systems characterized by dampers placed so that they connect each storey to a fixed point (as it is for the MPD system) display larger efficiency in energy dissipation than systems characterized by interstorey damper placement (traditional placement). The results also indicate that the forces exerted through the dampers of the MPD system and of the other damping systems considered are comparable in size. Two ways of implementing MPD systems in actual building structures are also presented: direct implementation (dampers connect each storey to the ground) and indirect implementation (dampers connect each storey of the base structure to a support structure: stiff vertical element, e.g. the conventional concrete core of the stairs/elevator typically found in r.c. constructions). Numerical results indicate that (provided that the support structure is characterized by a relatively large lateral stiffness) direct and indirect implementations lead to similar damping effect on the base structure without increasing the dynamic actions upon the support structure. Illustrative examples for the technical feasibility of both direct and indirect implementations are also provided.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
