Blast and Impact Loading and Response of Structures
Full Session with Abstracts
Steel gravity frames commonly used United States building construction practice, but they are potentially vulnerable to disproportionate collapse under column loss, as has been shown by recent experimental and analytical studies. To overcome these vulnerabilities, a new type of connection for the mitigation of disproportionate collapse in steel gravity frames subjected to column loss has been developed. These “enhanced” gravity connections, which could be implemented in new or existing structures, incorporate long-slotted steel plates that are welded to the column and bolted to the top and bottom flanges of the beam.
This presentation shows results from a rigorous experimental program designed to characterize the key geometric factors influencing the coupled flexural-axial performance of these enhanced connections. Long-slotted plates were axially tested in a single-lapped bolted configuration under several different loading protocols, including monotonic and reversed cyclic loading, to-characterize the behavior and failure modes of the components. The results from these component tests were used to further validate a previously developed component-based model that accounts for bolt pre-tension and slot length. This component-based model, in turn, was used to demonstrate the performance of the enhanced steel gravity connections subjected to a column loss.
This presentation will provide the audience with an improved understanding of the key issues influencing the performance of steel gravity connections subjected to column removal and demonstrate an economically viable strategy for enhancing the robustness of steel gravity frames. This research also supports the development of the new ASCE/SEI Disproportionate Collapse Mitigation Standard and the Alternative Load Path Analysis Guidelines being developed by the ASCE/SEI Disproportionate Collapse Technical Committee.