Compact Hybrid Simulation System: Validation and Applications for Braced Frames Seismic Testing

Hybrid Simulation (HS) is a well-established testing method that combines both experimental and analytical components to evaluate the performance of structures under extreme events, commonly earthquakes. While several configurations and systems are available around the world to conduct HS, one goal of this paper is to document the development and verification of a compact HS setup at the University of Nevada, Reno to be used for tackling new research problems and educational purposes. A new substructured HS approach is proposed for seismic testing of concentric-braced frames (CBFs) with focus on capturing brace buckling and low-cycle fatigue induced-rupture. The paper presents the capabilities and verification methods for the developed system for slow and real-time HS testing with two different alternatives for the computational substructures: Simulink and OpenSEES along with OpenFresco. Two new applications were pursued to demonstrate HS testing of CBFs. The first used cyclic loading and HS under earthquake loading to capture brace buckling and failure to compare damage accumulation and brace fatigue life through rupture. The second application used HS testing to investigate the effect of earthquake duration on seismic performance of CBFs. The two applications demonstrate that the proposed HS approach can be potentially used to accurately capture CBFs seismic behavior and provide new datasets for modeling brace buckling and rupture under realistic earthquake loading. The paper also provides a brief discussion on the potential use of the compact HS setup for developing teaching modules.