Review of the second-order moment amplification factors in AS4100 for the system design approach. Issue 4 (1st December 2016)

• Record Type: Journal Article
• Authors: Iu, C. K.
• Is Part Of: Australian journal of structural engineering. Volume 17:Issue 4(2016)
• Page Start: 215
• Page End: 224
• Publication Date: 2016-12-01
• Subjects: Moment amplification factor -- braced frame -- sway frame -- elastic buckling load -- system design approach; Structural engineering -- Periodicals; Structural engineering -- Australia -- Periodicals; Electronic journals; 624.1
• DOI: 10.1080/13287982.2016.1270627
• Languages: English
• ISSNs: 1328-7982

Abstract

Abstract: The first-order elastic analysis cannot capture the second-order effects owing to the change in structural geometry, such as P-Δ and P-δ effect, which can cause the second-order moment in order to deteriorate the stiffness of a structure. Unfortunately, the first-order elastic analysis is prevalent in the design office and the current practical engineers have not yet well equipped for manipulating the advanced analysis for design purpose. To this end, AS4100 stipulates the design calculation of moment amplification factor for the braced and sway member continuous in a framed structure in Section 4 of the method of structural analysis as a system approach; specifically for an axially compressive loaded column in either a braced or sway frame. However, in this study, it is shown that the moment amplification factors as a system approach is not as effective and sophisticated as the member design approach. In this regard, this paper reviews the moment amplification factor for the second-order effects on a rectangular portal frame with recourse to the first-order elastic analysis, and finally discusses an issue between the second-order moment amplification factor and the member buckling design, which can facilitate the design section of the system approach in AS4100 in alignment with the advanced analy"?>sis for the future system design approach.