Experimental investigations on inelastic behaviour and modified Gerber joint for double-span steel trapezoidal sheeting
2020 (English) In: Structures, E-ISSN 2352-0124, Vol. 24, p. 514-525Article in journal (Refereed) Published
Abstract [en]
Cold-formed steel trapezoidal profiles provide efficient solutions for roofing and often use the Gerber joint to effectively utilize capacities. The previous design of Gerber joint was sensitive to uneven distribution of loads and accidental loads, which imposed bending moments in the joint and lead to its failure. In this experimental program, the design of Gerber joint has been modified to work as a hinge under service loads and carry moments in accidental conditions. Also, the design of CFS is based on elastic methods that underestimate their capacity, especially for multi-span systems. Full-scale tests were conducted on highly stiffened double-span trapezoidal sheeting profiles with modified Gerber joint to investigate elastic capacity, inelastic behaviour, moment redistribution in the post-elastic phase, ultimate load capacity and feasibility of modified Gerber joint. Comparison of elastic load capacity with EWM and DSM predictions revealed that EWM design predictions were conservative by 30% while DSM predictions were accurate. For multi-span application, residual moment capacity ratios of 0.76 and 0.81 in the post-elastic phase allowed for moment redistribution and increased ultimate load capacity by 7.14% and 8.80% for 0.85 mm and 1 mm thick profiles respectively. Performance of modified Gerber joint to behave as a hinge under service loads and as continuous in the post-elastic phase was also found to be satisfactory. The study concluded that the economy in design and capacity utilization of multi-span CFS profiles can be improved by allowing for moment redistribution and using the modified Gerber joint.
Place, publisher, year, edition, pages Elsevier, 2020. Vol. 24, p. 514-525
Keywords [en]
Cold-formed steel, Trapezoidal sheeting, Inelastic behaviour, Post-elastic, Multi-span sheeting, Gerber joint, Direct strength method, Moment redistribution
National Category
Other Civil Engineering
Research subject Structural Engineering
Identifiers URN: urn:nbn:se:ltu:diva-77883 DOI: 10.1016/j.istruc.2020.01.042 ISI: 000519625500040 Scopus ID: 2-s2.0-85079168642 OAI: oai:DiVA.org:ltu-77883 DiVA, id: diva2:1396780
Note Validerad;2020;Nivå 2;2020-04-02 (alebob)
2020-02-262020-02-262025-02-19 Bibliographically approved