Seismic performance assessment of a low-rise thin reinforced concrete wall building with unconnected fiber reinforced elastomeric isolators using real-time hybrid simulations

Abstract

Thin reinforced concrete wall (TRCW) buildings have become one of the most cost-effective and fastest options for housing construction. However, the performance of the TRCW building under seismic loads has limited energy dissipation capacity and is characterized by brittle failures with dimensions below those limited in international standards, which classifies these walls as ultra-thin. By contrast, unconnected fiber-reinforced elastomeric isolator (U-FREI) devices are a type of seismic isolators with a high deformation capacity, low-cost development, and simplified manufacturing and installation process. To leverage the advantages of both mentioned systems in a combined manner and reduce the structural vulnerability of this type of buildings, this study presents an evaluation of the seismic performance of unconnected fiber-reinforced elastomeric isolator (U-FREI) devices as a base isolation system for low-rise thin reinforced concrete wall (TRCW) buildings using real-time hybrid simulations (RTHS) as an innovative testing technique. RTHS, as a novel physical cybernetic testing technique, allows a dynamic system of interest to be sub-structured into two components: numerical and experimental. The numerical substructure used in this study corresponds to a 24 degrees of freedom (DOF) model that represents the dynamic behavior of a reference low-rise TRCW building. Moreover, the experimental substructure consisted of scaled U-FREI devices that replicated the dynamic response of the base isolation system of the building. To develop an interface between the two substructures, a horizontal transfer system (HTS) was implemented and coupled with a vertical transfer system (VTS). Using RTHS, the performance of the isolated TRCW building was evaluated under four seismic events: El Centro, Kobe, Loma Prieta, and Morgan, at a maximum acceleration of 0.70 g (6.87 m∙s−2). The implementation of U-FREI devices as base isolation system in a low-rise TRCW building allowed a reduction of the maximum drift by over 54.80 % in comparison with the fixed structure. Finally, the U-FREI devices seismic performance is discussed.