Keeping Cross-Frames and Diaphragms in Check (PDH)
Presented by: Brandon Chavel, Ronnie Medlock, John Holt, Michelle Romage-Chambers, and Devin Altman
Cross-frames and diaphragms are important steel bridge components as they provide stability to primary longitudinal girders and improve lateral or torsional stiffness and strength of the bridge system during construction and in-service loads. In horizontally curved bridges, they transfer forces between adjacent girders to provide equilibrium; in straight bridges, they have been historically designed to transmit lateral loads such as wind. Over the last few years, the steel bridge industry has seen a general increase in the size of cross-frames used in steel I-girder bridges across the country, in terms of both the individual member sizes and the connections themselves, resulting in significant inefficiencies that can be corrected. This three-part course will provide practical guidance on cross-frame design basics, recommendations, and in-depth examples. Lean-on bracing will also be presented as an efficient option for stability bracing, including the introduction of a new NSBA design guide. Attendees will come away with comprehensive detailing and design methods for efficient and cost-effective cross-frames.