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Paper 31

Local and Global Stability Analysis of a Large Free Span Steel Roof Structure

Z. Nagy1, M. Cristutiu2 and Z. Kiss1
1Engineering Structures Department, Technical University of Cluj, Romania
2Department of Architecture, "Politehnica" University of Timisoara, Romania

Keywords: large span space trusses, hollow sections, TT and KK welded joints, local and global stability analysis, finite element joint modelling.

full paper (pdf) - reference

The paper describes the applied structural solution to the design of the roof structure for an indoor sport arena in the city of Cluj, Romania. The usual geometry of that kind of facility imposes a large free span (63.90 m) steel structure. The space truss is realized using SHS profiles and welded joints. The paper content is limited only to the large span roof structure and summarizes the results of the numerical study performed by the authors and gives details concerning the local and global stability analysis of the structural members and joints under different load combinations.

A short description of the whole building is given, as it was formulated in the design requirements. Basic information about design loads, structural solution and conceptual design of the roof structure are given. Triangular shaped spatial trusses at 10.60 m centres were designed. The truss section is 3600 mm wide by approximately 4000 mm deep (variable along the span).

Next the particular design problems, such as connection details between the steel and concrete structure, global stability checks and joint checks are presented. Using a very efficient design tool for the global stability checks, a step by step structural performance improvement strategy is presented. For the TT and KK welded joint designs, local brace failure (yielding, local buckling), the chord face plastification, chord punching shear, chord side wall failure, chord shear failure checks are necessary [1]. Due to limited range of validity of the analytical methods given by [1] (the semi-empirical formulae are developed for when the angle between the diagonal planes of the truss is 90 degrees), finite element modelling of the heaviest loaded truss joint was used and the results obtained were compared with those obtained by the analytical methods. As a first conclusion we can say that the finite element results and the analytical models used for the KK and TT welded joint designs provides a fair agreement for this particular space truss when the angle between the diagonal planes of the truss is 50 degrees even though the analytical models were developed for space trusses with an angles of 90 degrees.

Finally, some aspects of the fabrication and erection of the space truss structure are emphasized, which can have a deep impact to the overall cost.

References

1
J. Wardenier, J.A. Packer, X.L. Zhao, G.J. van der Vegte, "Hollow Sections in Structural Applications", Comité International pour le développement et l'Etude de la Construction Tubulaire.