A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Torsional Bracing of Cold-Formed Roof Systems
Cold-formed steel has been commonly used in metal building construction for over forty years. During that time there have been some problems associated with the roof bracing systems for standing seam roofs. To resist lateral-torsional (L-T) buckling these roofs systems require and independent bracing system to brace the Z-purlins. There is little or no restraint to L-T buckling with this system because the roof is only connected by sliding panel clips to the Z-purlin. Typically a lateral brace is provided to deal with L-T buckling but this type of strut or sag rod transmits the forces to the edge beam or eave strut and the amount of this force for design purposes is difficult to determine. This research investigates the use of a torsional brace system by conducting 21 experimental tests of a roof system using the Base Test Method per AISI TS-8-02. All tests were simple span with two Z-section purlins facing the same direction and supporting standing seam roof systems subjected to the uniform gravity loads. Z-purlins were braced at standard brace points. The variables of the test program included Z-purlins, spans, type of bracing, and bracing locations. These test investigated the use of a structural diaphragm as a torsional bracing between a pair of Z-purlins. This bracing system is compared and contrasted to a sag rod point bracing system that resists lateral translation of the purlin and provides very slight torsional rigidity. From the results, the average flexural strength of sections tested (Mnt) for both point bracing and torsional bracing were always greater than the flexural strength calculated using AISI C 3.1.
Torsional Bracing of Cold-Formed Roof Systems
Cold-formed steel has been commonly used in metal building construction for over forty years. During that time there have been some problems associated with the roof bracing systems for standing seam roofs. To resist lateral-torsional (L-T) buckling these roofs systems require and independent bracing system to brace the Z-purlins. There is little or no restraint to L-T buckling with this system because the roof is only connected by sliding panel clips to the Z-purlin. Typically a lateral brace is provided to deal with L-T buckling but this type of strut or sag rod transmits the forces to the edge beam or eave strut and the amount of this force for design purposes is difficult to determine. This research investigates the use of a torsional brace system by conducting 21 experimental tests of a roof system using the Base Test Method per AISI TS-8-02. All tests were simple span with two Z-section purlins facing the same direction and supporting standing seam roof systems subjected to the uniform gravity loads. Z-purlins were braced at standard brace points. The variables of the test program included Z-purlins, spans, type of bracing, and bracing locations. These test investigated the use of a structural diaphragm as a torsional bracing between a pair of Z-purlins. This bracing system is compared and contrasted to a sag rod point bracing system that resists lateral translation of the purlin and provides very slight torsional rigidity. From the results, the average flexural strength of sections tested (Mnt) for both point bracing and torsional bracing were always greater than the flexural strength calculated using AISI C 3.1.
Torsional Bracing of Cold-Formed Roof Systems
Shadravan, Shideh (author) / Ramseyer, Chris (author)
AEI 2017 ; 2017 ; Oklahoma City, Oklahoma
AEI 2017 ; 708-720
2017-04-06
Conference paper
Electronic Resource
English
BENDING CAPACITY OF COLD-FORMED STEEL PURLINS WITH TORSIONAL BRACING USING THE BASE TEST
| British Library Conference Proceedings | 2007
| British Library Online Contents | 1999
| British Library Conference Proceedings | 2009
Torsional restraint of roof sheeting on cold-formed steel hat sections
| Elsevier | 2025
ROOF BRACING MATERIAL, ROOF STRUCTURE AND ROOF CONSTRUCTION METHOD
| European Patent Office | 2020