Theoretical and experimental studies of unbraced tubular trusses allowing for torsional stiffness

Chan, S. L.¹, Koon, C. M. ², Albermani, F. G. ³

¹Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hong Kong

²Buildings Department, Hong Kong SAR Government, Hong Kong

³Department of Civil Engineering, University of Queensland, Australia

Received February 14, 2001, Accepted January 30, 2002

ABSTRACT:

This paper describes the buckling phenomenon of a tubular truss with unsupported length through a full-scale test and presents a practical computational method for the design of the trusses allowing for the contribution of torsional stiffness against buckling, of which the effect has never been considered previously by others. The current practice for the design of a planar truss has largely been based on the linear elastic approach which cannot allow for the contribution of torsional stiffness and tension members in a structural system against buckling. The over-simplified analytical technique is unable to provide a realistic and an economical design to a structure. In this paper the stability theory is applied to the second-order analysis and design of the structural form, with detailed allowance for the instability and second-order effects in compliance with design code requirements. Finally, the paper demonstrates the application of the proposed method to the stability design of a commonly adopted truss system used in support of glass panels in which lateral bracing members are highly undesirable for economical and aesthetic reasons.

Keywords:

buckling; tubular sections; torsional stiffness; advanced analysis; nonlinear integrated design and analysis.