UC Irvine

This dissertation explores the application of Buckling-Restrained Braces (BRBs) in bridge retrofitting, advancing their use through consistent design approaches and developing prequalification protocols. Further, it includes parameter calibration for a nonlinear BRB hysteretic model within a widely used structural analysis software (CSi Bridge) that will allow designers to improve their modeling of BRBs on bridge projects. Initial work evaluates the seismic performance of BRBs in steel truss bridges under parametric design scenarios. By analyzing retrofitting schemes for existing bridges, the study identifies optimal BRB configurations and establishes a prequalifying testing protocol tailored to these applications, ensuring compatibility with current industry standards. The investigation then shifts to reinforced concrete (RC) bent bridges, focusing on their unique demands, particularly for skewed configurations. Finite-element analyses across a range of skew angles identify key BRB demands and inform the development of prequalification protocols specific to RC bent bridges. These protocols are validated against existing standards, offering insights into their application in varied seismic scenarios. The research further observes BRB performance in RC bent bridges under near-fault (NF) seismic conditions, addressing the amplified demands posed by intense velocity pulses and directional effects. This research culminates in the development of NF-specific testing loading protocols that align with the unique characteristics of NF ground motions, leading to testing requirements to ensure robust BRB performance in retrofitting projects near active fault lines. Finally, the dissertation introduces identified cyclic hardening parameters for BRBs within the CSi Bridge software (Computers and Structures, Inc., 2023), bridging the gap between physical testing and computational modeling. The calibrated models enable an accurate representation of BRB behavior under cyclic demands, supporting designers in integrating BRBs into bridge retrofits with greater reliability. Through these contributions, the dissertation offers comprehensive frameworks for BRB application, encompassing design, testing, and modeling, thereby enhancing the ability of designers to increase the seismic resilience of various bridge types using BRBs across varied seismic conditions.