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Rotational stiffness of cold-formed steel roof purlin–sheeting connections
Citation
Zhao, C and Yang, J and Wang, F and Chan, AHC, Rotational stiffness of cold-formed steel roof purlin-sheeting connections, Engineering Structures, 59 pp. 284-297. ISSN 0141-0296 (2014) [Refereed Article]
Copyright Statement
Copyright 2013 Elsevier Ltd.
DOI: doi:10.1016/j.engstruct.2013.10.024
Abstract
Cold-formed steel (CFS) sections are commonly used in modern roof construction. Most purlin members
are of thin-walled open cross section. They are usually subjected to roof loading at the top flange in either
an upward or a downward direction. The load application points, where the sheeting/purlin connections
are located, are often eccentric to the shear centre, and thus inevitably generate a torsional moment that
will induce twisting and/or warping deformations in addition to bending deflection. This type of complexity
associated with the loading conditions will be exacerbated by the occurrence of single- or
mixed-mode buckling (e.g. overall, distortional and local buckling) due to compression flanges tending
to move sideways. The connections between purlin and roof sheeting provide a restraining effect on purlin
members by preventing such lateral and twisting movements, and thus have a beneficial effect on
their load-carrying capacity. In design practice, this effect should be taken into account from a design efficiency
perspective. To this end, a key step is to quantify the rotational restraint stiffness by using
an engineering-orientated model. This paper firstly reports a series of torsional restraint tests (F-tests)
for both sigma and zed sections. Two loading directions were examined by adjusting the purlin fixing
direction. The rotational angles between the connected flange and sheeting were recorded at each loading
step, from which the moment–rotation curves were produced and presented for each test case. A linear
relationship has been observed for the moment–rotation relationship from all test specimens. Secondly, a
hand calculation model for calculating the rotational stiffness at each connection was developed. In that
model, the rotation was deemed to be primarily caused by the localised deformation of the roof sheeting
and the distortional deformation of the purlin flange. The rotation caused by the separation of connection
was found to be negligible. The model was validated by the experimental test results and an example was
presented to demonstrate the application of the model proposed. The rotational stiffness calculated by
this model can be used to evaluate the input parameters required for numerical modelling of purlin–
sheeting interaction.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | cold-formed steel, purlin, roof sheeting, rotational stiffness, connections, analytical method, experimental studies |
Research Division: | Engineering |
Research Group: | Civil engineering |
Research Field: | Structural engineering |
Objective Division: | Construction |
Objective Group: | Construction materials performance and processes |
Objective Field: | Metals |
UTAS Author: | Chan, AHC (Professor Andrew Chan) |
ID Code: | 100999 |
Year Published: | 2014 |
Web of Science® Times Cited: | 26 |
Deposited By: | Office of the School of Engineering |
Deposited On: | 2015-06-05 |
Last Modified: | 2017-11-06 |
Downloads: | 0 |
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