Influence of modelling of steel link beams on the seismic response of EBFs

This paper investigates the effectiveness of some common and simple models of steel link beams in the seismic assessment of eccentrically braced frames. These models are based on the Euler-Bernoulli beam with concentrated flexural plastic hinges and consider ending springs to simulate the inelastic shear and flexural responses of the link. They do not allow the effects of both isotropic and kinematic hardening to be separately evaluated but considers an equivalent kinematic hardening. The benchmark is represented by the seismic response obtained by means of a simple but refined link model that has recently been proposed by the writers and that takes into account both kinematic and isotropic hardening. The accuracy of this model has been proved by several numerical tests on short, intermediate length and long links. To perform an extensive parametric investigation, the numerical analyses are first carried out on equivalent single-storey systems subjected to artificial accelerograms. Then, multi-storey systems subjected to either artificial or natural accelerograms are investigated. These systems are characterised by different mechanical lengths of the links and, in the case of multi-storey systems, by different numbers of storeys.