Seismic retrofit of structures using steel frames with viscoelastic hinges

Abstract

In this paper a new seismic retrofit system composed of a steel frame with viscoelastic hinges is proposed and its applicability and efficiency are evaluated in a theoretical framework. First, the mechanical behavior of viscoelastic hinges and the system are studied and the related formulas are derived. The analytical model of the proposed seismic damper is established first, and the damper is subjected to cyclic loads to compare its hysteretic behavior with the one from the formulation. In order to further evaluate the efficiency of this system, the validated analytical model is used in seismic retrofit of a case study structure to reach the collapse prevention performance under the maximum considered earthquake hazard level. The seismic performance of the analysis model is compared before and after retrofit in terms of maximum interstory drift ratio, residual displacement, and energy dissipation of structural members and dampers. The results show that the proposed damper can be used to reach the stipulated drift limit state. Furthermore, the inelastic energy dissipated by the structural members is reduced drastically and the structure can be effectively protected against irreversible damages due to inelastic deformations.