Challenges and Lessons Learned From Pseudo-Dynamic Hybrid Simulations on Ductile Steel Braced Frame Systems

Abstract

Performance-based seismic design, which emerged more than two decades ago, requires accurate numerical models to capture the response of structural elements that undergo inelastic deformations under random loading histories. High-fidelity benchmark test results under real natural hazards are therefore required to assist researchers and practitioners with this effort. Substructuring pseudo-dynamic hybrid simulation (PsDHS) is an efficient, yet effective testing method for evaluating the system-level response of structures under extreme loading scenarios, and for forming a database of high-fidelity benchmark test results. In PsDHS, the response of the critical structural components is captured in a laboratory through physical testing and is integrated with the numerical response of the remainder of the structure in a numerical model, by establishing a communication framework between the two. The former is referred to as a physical substructure and the latter is often referred to as the integration module. Despite its efficiency and effectiveness, large-scale hybrid simulation introduces researchers to a range of non-trivial challenges, especially in laboratories that are new to the methodology. This paper presents challenges and lessons learned from 21 large-scale pseudo-dynamic hybrid simulations on different ductile steel braced frame systems including a buckling-restrained braced frame (BRBF), a special concentrically braced frame (SCBF), a yielding brace system (YBS) equipped with cast steel yielding connectors (YCs), and eccentrically braced frames (EBFs) designed with cast steel replaceable modular yielding links (CMLs). Details for each hybrid simulation including the experimental setups, reference buildings, earthquake records, etc. along with selected results are presented. Challenges that were faced in each hybrid simulation related to hardware, the control system, integration schemes, etc., and attempted solutions are discussed. The findings from each set of hybrid simulations on each braced frame system are summarized. The experimental results are organized as a dataset in an online data repository, which is available for download. The organization of the dataset is presented to facilitate access to the experimental results. In the end, concluding remarks and visions for future research are presented.