Use of a High-Precision Digital Displacement Encoder for Hybrid Simulation of Seismic Response of Stiff Specimens

Abstract

Squat reinforced concrete shear walls typically comprise the lateral force resisting system in nuclear facility structures. The geometry and thickness of these walls contribute to an extremely high initial lateral stiffness. When conducting a hybrid simulation, a high stiffness presents a challenge for determining the dynamic response of such walls because very small displacements must be controlled. An extension of the hybrid simulation technique using a digital displacement encoder for high-resolution displacement feedback was developed, implemented, verified, and validated. Then a hybrid model that represents a nuclear facility structure with a large-scale squat wall physical specimen was designed. A ground motion excitation was selected and scaled to represent specific performance levels. These preparations for hybrid simulations of the seismic response of squat shear wall specimens, subjected to different ground motion sequences, are presented to illustrate the new developments. Guidelines are provided for future implementations of feedback instruments for servo-hydraulic systems to conduct hybrid simulation tests.