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Evaluation of post-weld treated steel welds subject to mechanical loading
Published in Hiroshi Yokota, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations, 2021
O.B. Friis, H.B. Blum, H.C. Yildirim
Cold-formed steel is due to its high strength to weight ratio often an attractive solution for structural members. Due to manufacturing techniques, cross-section often poses high slenderness properties, which can lead to buckling prior to reaching its yield load. It is a well knwon fact that due to the slender properties, such sections can be very sensitive to geometrical imperfections, which was discovered by Winter 1940 who modified findings on the strength of thin plates in compression by Von Karman 1932, to agree with experimental results. Major research within imperfections in cold-formed steel members were presented by Schafer and Peköz 1998, where different imperfections where characterized and the probability of occurrence of certain imperfections were discussed. Dubina and Ungureanu 2002 the effects of imperfections in cold-formed steel members have been analyzed, where it was shown that the both the failure mode and collapse load are greatly affected by the particular imperfection distribution.
Elevated Temperature Properties of Materials
Published in Yong Wang, Mahen Mahendran, Ashkan Shahbazian, Fire Performance of Thin-Walled Steel Structures, 2020
Yong Wang, Mahen Mahendran, Ashkan Shahbazian
In fire engineering calculations of structural resistance in fire, it is necessary to have accurate and reliable information on thermal and mechanical properties of materials of the structure. Compared to hot-rolled steel structures, there are more issues for the material properties of cold-formed thin-walled steel structures. Cold-formed steel structures are made by cold working of thin-walled cold-rolled steel strips into structural shapes. This introduces strain hardening around corners, and the amount of strain hardening may be affected by the thickness of the structure. Lightweight board and insulation materials, such as gypsum plasterboard and mineral fibres, are used in thin-walled steel construction systems. The thermal properties, in particular thermal conductivity, of these materials are not constant. Since temperatures attained in steel sections of thin-walled construction are critically dependent on insulation properties, thermal properties of insulation materials and gypsum plasterboards should be provided. This chapter will review available data from major sources of relevant information in literature and make recommendations.
Metal studs
Published in Gary Anglin, Introduction to Estimating, Plan Reading and Construction Techniques, 2019
“Cold-formed steel” is a term used to describe steel products made from previously produced sheet steel. The sheet steel is rolled or bent and pressed into shape by machine at room temperature. The use of the word “cold” differentiates it from the hot temperatures sometimes used to make structural steel (not all structural steel is made “hot” because some steel shapes are assembled from already produced products. See Part 5).
Investigation of torsional bracing of cold-formed steel roofing systems
Published in Journal of Structural Integrity and Maintenance, 2019
Shideh Shadravan, Mark Emde, Chris Ramseyer
In the construction industry, cold-formed steel construction has been proven to save money and materials due to the member’s high strength-to-weight ratio (Polyzois & Sudharmapal, 1988). These members are formed quickly and efficiently using continuous flow manufacturing roller mills, which can allow for easy changes in the design of a member with the adjustment of a single piece or setting. Metal building purlins or roof beams are increasingly provided in longer spans as the standard bay spacing increases. The original connection of roof panels to the beams was by using self-tapping screws directly connecting the purlin and panels. This is often referred to as a through-fastened system. The self-tapping screws include a rubber washer to create an exterior seal with the roof. But thermal expansion and contraction causes the roof panel to move relative to the screw. And weather tightness is only effective for fairly short roof spans where the thermal expansion and the elongated hole do not exceed the width of the washer. So as beam spans increased, and panel lengths increased, the amount of thermal movement increased and the screw holes became an increasing source of water leaks. Studies have shown that through-fastened roofing systems provide adequate lateral stability to the top flange of the purlins (Brooks and Murray, 1989; Anderson & Murray, 1990; Brooks & Murray, 1990; Katnam, Van Impe, Lagae, & De Beule, 2006; Lee & Murray, 2001; Murray & Elhouar, 1994; Neubert & Murray, 2000a, 2000b; Thottunkal, 2004; Wills & Wallace, 1990; Yu & Schafer, 2002, 2005, 2006, 2007; Zhao, 2014), but expansion and contraction allowed for leaks that shortened the life of the roof. Another disadvantage of the through-fasten roofing system is that insulation can only be installed between purlins. This creates a less energy efficient building due to thermal bridging and a more labor-intensive installation process (Yu & Schafer, 2005).