Finite element analysis of flexural response of steel joist top chord extensions. (March 2022)

• Record Type: Journal Article
• Authors: Assily Alegre, Michel-Ange; Tremblay, Robert
• Is Part Of: Journal of constructional steel research. Volume 190(2022)
• Publication Date: 2022-03
• Subjects: Cantilever -- Finite element method -- Material characterization -- Steel joists -- Top chord extension; Steel, Structural -- Periodicals; Building, Iron and steel -- Periodicals; Acier de construction -- Périodiques; Construction métallique -- Périodiques; 624.1821
• DOI: 10.1016/j.jcsr.2021.107122
• Languages: English
• ISSNs: 0143-974X

Abstract

Abstract: This article investigates the flexural response of cantilevered top chord extensions of open web steel joists used in building structures. Currently, no design guidance is available to assess the bending capacity of these members with consideration of local and lateral-torsional buckling failure modes. The objective of the study was to develop a numerical finite element model capable of predicting the behaviour of 13 joist top chord extensions tested in a previous experimental program. The specimens studied have different cross-sections and restraint conditions. Residual stresses and geometric imperfections were included in the models. To achieve good correlation with the test results in terms of ultimate strength, failure mechanism and moment-deflection response, the model had to include the spacers between the top chord individual members, the load distribution system and the supporting beam used in the tests, as well as translational springs simulating lateral and torsional restraining effects of the steel deck panels. The developed finite element model was capable of reliably predict the measured flexural capacities and failure modes of the specimens. It also permitted to confirm that the steel deck panels and the spacers can positively impact the flexural capacity of the top chord extensions. Graphical abstract: Unlabelled Image Highlights: Numerical finite element model of open web steel joists with cantilevered top chord extensions was developed Extensions with different cross-sections and restraint conditions, tested in a previous experimental program, were modelled Residual stresses and geometric imperfections were included in the finite element models Finite element model reliably predicted ultimate strength, failure mechanism and moment-deflection response The FE model also permitted to confirm that steel deck panels and spacers can impact top chord extensions flexural capacity