Energy factors of trilinear SDOF systems representing damage-control buildings with energy dissipation fuses subjected to near-fault earthquakes

Abstract

This paper presents the energy factor of trilinear single-degree-of-freedom (SDOF) systems representing low-to-medium rise damage-control buildings equipped with energy dissipation fuses under near-fault earthquake ground motions, and the focus is given to the ultimate stage of the systems. The hysteretic behaviour of a damage-control building structure with energy dissipation fuses is firstly idealised by the trilinear kinematic model, and the rationality of the trilinear idealisation is validated by the test result of a representative damage-control structure. Subsequently, the hysteretic law is assigned to SDOF systems and the seismic demand of the systems quantified by the energy factor is examined through extensive nonlinear dynamic analyses with an ensemble of near-fault earthquake ground motions as input excitations. Based on the statistical investigations of more than twenty-one (21) million inelastic spectral analyses of SDOF systems subjected to ground motions, the effect of the post-yielding stiffness ratios and the corresponding inelastic deformation range of the multiple yielding stages on the energy factor of the trilinear SDOF systems are examined in detail, and the corresponding empirical expressions for quantifying the energy factor demand are also developed. The observations of this work show that the energy factor of trilinear SDOF systems subjected to near-fault earthquake ground motions is appreciably influenced by the hysteretic parameters in multiple yielding stages, and engineers have sufficient flexibility to modulate the seismic energy balance of the system by adjusting these influential parameters. The proposed empirical expressions offer a practical tool for estimating the energy factor of a low-to-medium rise damage-control buildings equipped with energy dissipation fuses subjected to near-fault ground motions in the preliminary design phase.