It is known that the seismic response of a structural system is highly influenced, in addition to the earthquake input, by the dynamic characteristics of the system itself. This paper presents a procedure for the identification of the characteristics of the structural system resisting to horizontal loads which enables to satisfy given seismic performance objectives. This is achieved by considering a total conceptual separation between the structural systems resisting to vertical and horizontal loads. The proposed procedure is first briefly developed in general within a Performance-Based Seismic Design (PBSD) framework and then fully applied to the case study of a five-storey steel building structure. It is composed of three basic steps: (1) calibration of the fundamental characteristics which should be possessed by the structural system resisting to the horizontal loads to satisfy given performance objectives, (2) identification of the physical and geometrical characteristics of the single structural elements which constitute the horizontal resisting system, (3) verification, by means of appropriate time-history analyses, of the seismic performances achieved. In detail, the horizontal resisting system is calibrated to satisfy a multiplicity of performance objectives through the identification of an "objectives curve", in the Force-Displacement diagram, of the mechanical characteristics of the structure. The calibration is obtained by methods/tools borrowed either from Direct Displacement-Based Design (DDBD) or Force-Based Design (FBD), depending on the specific performance objective to be imposed. The applicative example has been carried out with reference to three performance objectives and has led to the identification of an horizontal resisting system composed of special bracing elements capable of realizing a sort of properly-calibrated seismic isolation (“revised/tuned soft-storey” at the ground level) called crescent-shaped braces. The results obtained through non-linear dynamic analyses have shown that the proposed procedure leads to the congruity between the imposed and the achieved seismic performances.
An application of Displacement-Based Design approaches to a steel structure / Ricci I.; Gasparini G.; Silvestri S.; Trombetti T.. - ELETTRONICO. - Single Volume:(2009), pp. 347-358. (Intervento presentato al convegno XIII Convegno Nazionale “L’Ingegneria Sismica in Italia” ANIDIS 2009 tenutosi a Bologna nel 28 Giugno - 2 Luglio 2009).
An application of Displacement-Based Design approaches to a steel structure
RICCI, ILARIA;GASPARINI, GIADA;SILVESTRI, STEFANO;TROMBETTI, TOMASO
2009
Abstract
It is known that the seismic response of a structural system is highly influenced, in addition to the earthquake input, by the dynamic characteristics of the system itself. This paper presents a procedure for the identification of the characteristics of the structural system resisting to horizontal loads which enables to satisfy given seismic performance objectives. This is achieved by considering a total conceptual separation between the structural systems resisting to vertical and horizontal loads. The proposed procedure is first briefly developed in general within a Performance-Based Seismic Design (PBSD) framework and then fully applied to the case study of a five-storey steel building structure. It is composed of three basic steps: (1) calibration of the fundamental characteristics which should be possessed by the structural system resisting to the horizontal loads to satisfy given performance objectives, (2) identification of the physical and geometrical characteristics of the single structural elements which constitute the horizontal resisting system, (3) verification, by means of appropriate time-history analyses, of the seismic performances achieved. In detail, the horizontal resisting system is calibrated to satisfy a multiplicity of performance objectives through the identification of an "objectives curve", in the Force-Displacement diagram, of the mechanical characteristics of the structure. The calibration is obtained by methods/tools borrowed either from Direct Displacement-Based Design (DDBD) or Force-Based Design (FBD), depending on the specific performance objective to be imposed. The applicative example has been carried out with reference to three performance objectives and has led to the identification of an horizontal resisting system composed of special bracing elements capable of realizing a sort of properly-calibrated seismic isolation (“revised/tuned soft-storey” at the ground level) called crescent-shaped braces. The results obtained through non-linear dynamic analyses have shown that the proposed procedure leads to the congruity between the imposed and the achieved seismic performances.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
