Strength and stiffness parameters of energy dissipation devices for the seismic protection of building on soft soils

Abstract

Energy dissipation devices are continuously implemented in several buildings and bridges around the world. The dynamic characteristics of the strong motions in soft soil sites make attractive the use of this type of passive control system; however, its applicability remains limited. In spite of the important number of papers studying the seismic behavior of structures with passive control devices, only few of them consider low frequency excitations and even less studies combine low frequency excitations and yield type devices. One of the main impediments regarding to the use of energy dissipation devices is the lack of specific studies, showing their applicability as a function of the dynamic characteristics of structural systems with dissipation devices located on soft soil sites. This study conducts a parametric study of a single degree of freedom system with metallic yielding devices, with the aim of proposing graphs for the preliminary design of buildings with energy dissipation devices, by means of drift, frame ductility and dissipator ductility response spectra. The excitation of the models is a collection of seismic strong motions recorded in soft soil sites. 21,600 nonlinear time history analyses were processed for the entire combinations of the displacement and stiffness parameters of the structures and devices selected. The results allow an easy way to select initially the mechanical and geometrical properties of the energy dissipation devices with elastoplastic behavior, as a function of the fundamental period of the building. Finally a case study of a six-story RC building with metallic energy dissipation devices demonstrates the applicability of the proposed response spectra.