Among the resisting steel types suitable for the design of high ductility structures, Eurocode 8 proposes MRFs and EBFs. Also if the formers are generally considered a more efficient structural solution for high-ductility design, they suffers a strong weakness in the lateral stiffness creating, during the design process, cumbersome procedures to avoid excessive lateral displacements maintaining quite high ductile behaviour under design seismic actions. In many cases, the design process produces not optimized structural members, oversized respect to the minimum seismic requirements due to lateral deformation limitations. On the contrary, EBF combines high lateral stiffness furnished by bracing elements and high dissipative capacities furnished by plastic hinges developed in links. Eurocode 8 proposes a design procedure for realizing high ductility EBF in which iterative checks are required to properly design the links assigning to every link a defined level resistance dependant on all other links resistance. The present paper investigates the seismic behaviour of EBFs using the Incremental Dynamic Analysis technique in order to explore their mechanical response under increasing seismic action levels. A set of steel structures is designed according to Eurocode 8. The numerical simulations are executed considering the variability of both steel mechanical properties and seismic input, aiming to a complete probabilistic characterization of mechanical response of the system and deeply analyzing the effective level of structural safety and the ability to internally redistribute plasticizations during the earthquake. Structural safety conditions will be defined according to a multi-level performance approach. The paper presents also some final suggestions for possible improvements/simplifications in EBF design.
INFLUENCE OF STEEL MECHANICAL PROPERTIES ON EBF SEISMIC BEHAVIOUR
CAPRILI, SILVIA;SALVATORE, WALTER
2011-01-01
Abstract
Among the resisting steel types suitable for the design of high ductility structures, Eurocode 8 proposes MRFs and EBFs. Also if the formers are generally considered a more efficient structural solution for high-ductility design, they suffers a strong weakness in the lateral stiffness creating, during the design process, cumbersome procedures to avoid excessive lateral displacements maintaining quite high ductile behaviour under design seismic actions. In many cases, the design process produces not optimized structural members, oversized respect to the minimum seismic requirements due to lateral deformation limitations. On the contrary, EBF combines high lateral stiffness furnished by bracing elements and high dissipative capacities furnished by plastic hinges developed in links. Eurocode 8 proposes a design procedure for realizing high ductility EBF in which iterative checks are required to properly design the links assigning to every link a defined level resistance dependant on all other links resistance. The present paper investigates the seismic behaviour of EBFs using the Incremental Dynamic Analysis technique in order to explore their mechanical response under increasing seismic action levels. A set of steel structures is designed according to Eurocode 8. The numerical simulations are executed considering the variability of both steel mechanical properties and seismic input, aiming to a complete probabilistic characterization of mechanical response of the system and deeply analyzing the effective level of structural safety and the ability to internally redistribute plasticizations during the earthquake. Structural safety conditions will be defined according to a multi-level performance approach. The paper presents also some final suggestions for possible improvements/simplifications in EBF design.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
