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Lateral support of axially loaded columns in portal frame structures provided by sheeting rails

Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008.

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Main Author: Louw, Graeme Scott
Other Authors: Dunaiski, P. E.
Format: Thesis
Language:English
Published: Stellenbosch : Stellenbosch University 2008
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access_status_str Open Access
author Louw, Graeme Scott
author2 Dunaiski, P. E.
author_browse Dunaiski, P. E.
Louw, Graeme Scott
author_facet Dunaiski, P. E.
Louw, Graeme Scott
author_sort Louw, Graeme Scott
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008.
format Thesis
id oai:scholar.sun.ac.za:10019.1/1585
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:40:57.522Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2008
publishDateRange 2008
publishDateSort 2008
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/1585 Lateral support of axially loaded columns in portal frame structures provided by sheeting rails Louw, Graeme Scott Dunaiski, P. E. Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Axially loaded columns Portal frame structures Sheeting rails Lateral support Theses -- Civil engineering Dissertations -- Civil engineering Civil Engineering Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008. Doubly symmetric I-section columns are often utilised in portal frame construction. The sheeting (or cladding) is carried by sheeting rails connected to the outer flange of these columns. Although it is common practice to include the sheeting rails in the longitudinal bracing system, by connecting the sheeting rail to the cross-bracing, designers must be wary because the connection between column and sheeting rail will not prevent twisting of the columns cross-section. It has been shown ([11], [12], [17]), that by including this eccentric restraint into the bracing of the column, that a torsional-flexural buckling mode of failure can occur when the column is subjected to axial load only. It was seen that this phenomenon is provided for in BS 5950 [18], but is not present in many other design codes of practice, in spite of this phenomenon being relatively well known. In some cases the compression resistance of a column can be significantly reduced when compared to that of a flexural buckled configuration. Previous work performed by Helwig and Yura [15] proposed specific column to sheeting rail connections which would allow for the sheeting rails to be used as elastic torsional braces and effectively rigid lateral braces. However, it is the objective of this investigation to determine if it is possible to include the eccentric sheeting rails into the bracing system, even when using a relatively simple cleat connection with only two bolts onto the sheeting rail. The objective of the research was investigated by conducting experimental tests coupled with a series of detailed finite element analyses. The purpose of the experimental set-up was to investigate the behaviour of a column laterally supported on one flange by a continuous sheeting rail and to compare it to the behaviour of a column laterally supported on both flanges by means of fly-braces (“kneebraces”). The behaviour of the columns, as determined by the experimental tests, was validated by the finite element analyses. The evident conclusion that can be drawn is that, for the case of a continuous sheeting rail, connected to column simply by two bolts and a cleat, that sufficient torsional restraint is provided to the column to prevent torsional-flexural buckling from being critical. This result is helpful, as it means that the buckling capacity of a column can be increased four-fold by enforcing the second flexural buckling mode instead of the first mode through utilising a continuous sheeting rail connected to a cross-bracing system as longitudinal bracing on the columns. This can be achieved without the need to provide any specific detailing to the column to sheeting rail connection. It is however, recommended that further experimental work be conducted on varying lengths of column in order to further validate the results of this work. 2008-11-26T11:03:04Z 2010-06-01T08:27:57Z 2008-11-26T11:03:04Z 2010-06-01T08:27:57Z 2008-12 Thesis http://hdl.handle.net/10019.1/1585 en Stellenbosch University application/pdf Stellenbosch : Stellenbosch University
spellingShingle Axially loaded columns
Portal frame structures
Sheeting rails
Lateral support
Theses -- Civil engineering
Dissertations -- Civil engineering
Civil Engineering
Louw, Graeme Scott
Lateral support of axially loaded columns in portal frame structures provided by sheeting rails
title Lateral support of axially loaded columns in portal frame structures provided by sheeting rails
title_full Lateral support of axially loaded columns in portal frame structures provided by sheeting rails
title_fullStr Lateral support of axially loaded columns in portal frame structures provided by sheeting rails
title_full_unstemmed Lateral support of axially loaded columns in portal frame structures provided by sheeting rails
title_short Lateral support of axially loaded columns in portal frame structures provided by sheeting rails
title_sort lateral support of axially loaded columns in portal frame structures provided by sheeting rails
topic Axially loaded columns
Portal frame structures
Sheeting rails
Lateral support
Theses -- Civil engineering
Dissertations -- Civil engineering
Civil Engineering
url http://hdl.handle.net/10019.1/1585
work_keys_str_mv AT louwgraemescott lateralsupportofaxiallyloadedcolumnsinportalframestructuresprovidedbysheetingrails