Proceedings of the Annual Stability Conference Structural Stability Research Council San Antonio, Texas, March 21-24, 2017 End plate stability in thermally-improved steel cladding details Kara D. Peterman 1 , Mark D. Webster 2 , James A. D’Aloisio 3 , Jerome F. Hajjar 4 Abstract 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. 1. Introduction to structural thermal breaks This research is part of a larger effort which explores approaches for developing thermal breaks to mitigate energy loss in steel building structures. This energy loss is formed by structural steel elements that pass through the building envelope, which can potentially act as thermal bridges due to their ability to conduct heat. Thus, heating and cooling are transferred to the exterior and interior, which increases building energy consumption and can contribute to condensation and reduced building occupant comfort. The aim of this project is to explore and validate several structural thermal break concepts and develop associated design recommendations for mitigating the loss of energy and other related issues in steel building structures. By identifying critical details susceptible to becoming thermal bridges, proposing realistic and constructible mitigation strategies, and validating these strategies experimentally and computationally, the work aims to propose solutions for practicing engineers. 1 Assistant Professor, University of Massachusetts Amherst, formerly Postdoctoral Research Associate, Northeastern University <[email protected]> 2 Senior Staff II - Structures, Simpson, Gumpertz, and Heger, <[email protected]> 3 Principal, Klepper Hahn and Hyatt, <[email protected]> 4 CDM Smith Professor and Chair, Northeastern University, <[email protected]>
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Proceedings of the
Annual Stability Conference
Structural Stability Research Council
San Antonio, Texas, March 21-24, 2017
End plate stability in thermally-improved steel cladding details
Kara D. Peterman1, Mark D. Webster2, James A. D’Aloisio3, Jerome F. Hajjar4
Abstract
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.
1. Introduction to structural thermal breaks
This research is part of a larger effort which explores approaches for developing thermal breaks
to mitigate energy loss in steel building structures. This energy loss is formed by structural steel
elements that pass through the building envelope, which can potentially act as thermal bridges
due to their ability to conduct heat. Thus, heating and cooling are transferred to the exterior and
interior, which increases building energy consumption and can contribute to condensation and
reduced building occupant comfort. The aim of this project is to explore and validate several
structural thermal break concepts and develop associated design recommendations for mitigating
the loss of energy and other related issues in steel building structures. By identifying critical
details susceptible to becoming thermal bridges, proposing realistic and constructible mitigation
strategies, and validating these strategies experimentally and computationally, the work aims to
propose solutions for practicing engineers.
1 Assistant Professor, University of Massachusetts Amherst, formerly Postdoctoral Research Associate, Northeastern