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Residual shear capacity of cold-formed steel-to-sheathing screwed connections at elevated temperatures

Kun Liu (Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of Mining and Technology, Xuzhou, China and Xuzhou Key Laboratory for Fire Safety of Engineering Structures, China University of Mining and Technology, Xuzhou, China)
Wei Chen (Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of Mining and Technology, Xuzhou, China and Xuzhou Key Laboratory for Fire Safety of Engineering Structures, China University of Mining and Technology, Xuzhou, China)
Jihong Ye (School of Civil Engineering, Southeast University, Nanjing, China)
Jian Jiang (Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of Mining and Technology, Xuzhou, China)
Wenwen Chen (School of Civil Engineering, Southeast University, Nanjing, China)
Mingyue Zhao (School of Civil Engineering, Southeast University, Nanjing, China)

Journal of Structural Fire Engineering

ISSN: 2040-2317

Article publication date: 6 April 2021

Issue publication date: 24 May 2021

74

Abstract

Purpose

Most previous thermal-mechanical modeling of cold-formed steel (CFS) walls did not consider the failure of screwed connections under fire conditions because of the limited data of such connections at elevated temperatures.

Design/methodology/approach

In this study, 285 steady-state tests are conducted on CFS screwed connections with single-layer gypsum plasterboard (GPB) and Bolivian magnesium board (BMB) sheathing at ambient and elevated temperatures. The failure of these connections is described as the breaking of the loaded sheathing edge.

Findings

For the BMB sheathing screwed connections, hydrochloric acid gas is generated and released above 300°C, and the shear strength becomes much less than that of the GPB sheathing screwed connection above 370°C. Hence, BMB may not be suitable for use as the face-layer sheathing of CFS walls but is still recommended to replace GPB as the base-layer sheathing. The major influencing parameters on the shear strength of screwed connections are identified as the type of sheathing material and the loaded sheathing edge distance.

Originality/value

Based on the previous and present test results, a unified expression for the residual shear strength of screwed connections with GPB and BMB is proposed at ambient and elevated temperatures with acceptable accuracy. It can be used as the basic input parameter of the numerical simulation of the CFS structures under fire conditions.

Keywords

Citation

Liu, K., Chen, W., Ye, J., Jiang, J., Chen, W. and Zhao, M. (2021), "Residual shear capacity of cold-formed steel-to-sheathing screwed connections at elevated temperatures", Journal of Structural Fire Engineering, Vol. 12 No. 2, pp. 212-233. https://doi.org/10.1108/JSFE-07-2020-0024

Publisher

:

Emerald Publishing Limited

Copyright © 2021, Emerald Publishing Limited

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