Hybrid simulation for earthquake response of semirigid partial-strength steel frames

The behavior of semirigid partial-strength connections has been investigated through either experimental component testing or detailed three-dimensional (3D) finite-element (FE) models of beam-column subassemblies. Previous experiments on semirigid partial-strength connections were conducted under idealized loads and boundary conditions, which do not represent real situations. In addition, the developed 3D FE models are computationally expensive and have primarily been used under monotonic loadings. Evaluating the full potential of any connection requires a system-level investigation, whereby the effect of the local behavior of the connection on the global response of the structural system is considered. Moreover, the connection should be tested under realistic load and boundary conditions and/or analyzed using an accurate yet computationally affordable analytical model. This paper represents a new system-level hybrid simulation application aimed at investigating the seismic performance of semirigid partial-strength steel frames with top and seat angles with double web-angle connections. The analytical component of the simulation comprises a detailed two-dimensional nonlinear FE model. The experimental component of the simulation consists of a full-scale beam-column subassembly with loading and boundary conditions that are in full interaction with the rest of the frame. The paper provides an overview of the hybrid simulation application and highlights the major results. The simulations were conducted at the Multi-Axial Full-Scale Sub-Structured Testing and Simulation Facility at the University of Illinois, which is part of the National Science Foundation Network for Earthquake Engineering Simulation.