End Plate Stability in Thermally-Improved Steel Cladding Details

Cladding details in steel structures that span the building envelope are particularly prone to thermal transfer, resulting in potential energy loss and condensation. In an attempt to effectively identify and mitigate these thermal bridges, a multi-year research effort was conducted to form design recommendations for practitioners based on thermal modeling, extensive experimental work, and computational modeling. While the project encompassed the thermal mitigation and structural performance of three principal cladding details—slab-supported shelf angles, roof posts, and canopy beams—this paper examines the difference in end plate stability between mitigated and unmitigated roof posts and canopy beams. To this end, cyclic and monotonic testing was conducted on mitigated and unmitigated details under combined axial and lateral load for the roof posts, and lateral load only for the canopy beams. Specimens were instrumented to capture end plate stability modes, post and beam curvature, anchor bolt forces, and strain in the end plates, posts, and beams. While analyses of the data do highlight variation in behavior, results presented herein suggest that the thermally-improved details perform commensurately to the unmitigated details.

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