Performance of cut-curved cold-formed steel channel sections for roof truss system
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Date
2018
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Teknologi Malaysia
Abstract
Nowadays, many roof truss structures are made of steel, especially cold-formed steel (CFS) due to several advantages such as the variety of configurations, shapes and sizes. The roof truss system is considered safe and secure when it is stabilised under impact forces in any direction of actions. The major problem that influences the stability of the roof truss system is buckling of the slender truss section, especially the top chord of the roof truss system. The curving process using the cold-curving method is unsuitable as the section tends to fail due to distortional and initial buckling. Thus, the cut-curved CFS section is proposed as a solution to resist the buckling phenomena on the compression member and to minimise the distortional effect during the curving process. The aim of this study is to propose a curved CFS channel section for use in the roof truss system design. The main objectives of the study are to evaluate the structural behaviour of cut-curved CFS channel section and to investigate the load-deformation behaviour of cut-curved CFS roof truss system. The experimental works involve the material properties test of CFS section, connection test, mechanical behaviour test of a cut CFS section, mechanical behaviour test of the strengthened cut-curved CFS section, flexural and compression behaviour test of cut-curved CFS section and lastly load-deformation behaviour test of cut-curved CFS roof truss system. The result of tests on the cut-curved CFS section is compared to the normal CFS section which is verified with Eurocode 3 and Direct Strength Method. From the individual test, the ultimate load of cut-curved CFS section increased between 7% to 15% for the flexural member and decreased between 30% to 38% for the compression member when compared to the normal CFS section. The result of the flexural and compression test on the members were analysed, hence the truss member is placed as a bracing to solve the compression weakness when the section is used in the roof truss system. Cut-curved CFS roof truss system increased the ultimate load capacity and minimise the effect of local and distortional buckling of the slender member nearest to the truss support which commonly occur on a normal CFS roof truss system. Finally, based on the findings of this study, the production method and the parameter equation for evaluating the cut-curved CFS channel section are recommended. Additionally, the design flowchart of cut-curved CFS column, beam and roof truss system is also proposed for the construction industry.
Description
Thesis (PhD. (Civil Engineering))
Keywords
Trusses—Design and construction, Roof trusses, Structural analysis (Engineering)
Citation
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