MODELLING OF HOLLOW STRUCTURAL SECTION TRUSSES

It has been recently advocated that a practical static design of hollow structural section (HSS) Warren and Pratt trusses, having either gapped or overlapped connections, can be performed on the basis of a force distribution obtained from an elastic analysis of the truss with either all the members pin-jointed or the web members pin-jointed to continuous chord members. However, at the service load level, gap-connected truss deflections have been previously underestimated by around 12%–15%. Laboratory testing of HSS trusses has accordingly been undertaken to establish experimental axial force and bending moment distributions and truss deflection patterns. Tests have been conducted on two large-scale, 12.0 and 12.2 m span, simply supported, HSS Warren trusses, comprised of 60° gap or overlap K-connections. Based upon the experimental behaviour of the two trusses and the theoretical analyses, it is shown that simple pin-jointed analysis is sufficient to give good predictions for web and chord member forces. ...