Experimentally Calibrated Nonlinear Hinge Models for H-Shaped Beams, HSS Columns, and H-Shaped Braces in Steel Frames

This study develops and validates a suite of computationally efficient nonlinear hinge models to enable accurate performance-based seismic assessment of steel moment-resisting frames (MRFs) and concentrically braced frames (CBFs). Derived from a comprehensive regression analysis of 66 cyclic tests on beams, columns, and braces, which include modern high-strength steels such as SM570 and SN490B, the proposed formulations comprise three specialized models: a flexural model for H-shaped beams, an axial model for H-shaped braces, and a flexural-axial interaction model for HSS columns. These models explicitly capture critical inelastic behaviors such as local buckling, asymmetric hysteresis, and strength degradation. Rigorous component-level validation was performed by benchmarking the proposed models against experimental results and code provisions, demonstrating substantially improved accuracy in predicting deformation capacity, strength, and asymmetric hysteretic response. The practical efficacy of the models was further demonestrated through system-level case studies of a 15-story MRF and a two-story CBF, analyzed within an ASCE 41 − 23 compliant framework integrating nonlinear static pushover analysis (NSPA) and the capacity spectrum method (CSM). The results demonstrate the proposed models' superior predictive accuracy, successfully quantifying global overstrength and identifying localized weak-story mechanisms that were not captured by the standard approach, providing engineers with a robust tool for performance-based seismic evaluation.