3 new articles about space structures from Journal of Constructional Steel Research
1. Advanced analysis and design of spatial structures
Journal of Constructional Steel Research
Volume 42, Issue 1, April 1997, Pages 21-48
Abstract
Modern limit-state design codes are based on limits of structural resistance. To determine the ‘true’ ultimate load-carrying capacity of spatial structures, an advanced analysis method which considers the interaction of actual behaviour of individual members with that of the structure is required. In the present work, a large-displacement inelastic analysis technique has been adopted to compute the maximum strength of spatial structures considering both member and structure instability. The actual behaviour of individual members in a spatial structure is depicted in the form of an inelastic strut model considering member initial imperfections as ‘enlarged’ out-of-straightness. The maximum strength of the strut is computed based on a member with ‘equivalent out-of-straightness’ so as to achieve the specification's strength for an axially loaded column. The results obtained by the strut model are shown to agree well with those determined using plastic-zone analysis. The nonlinear equilibrium equations resulting from geometrical and material nonlinearities are solved using an incremental-iterative numerical scheme based on generalised displacement control method. The effectiveness of the proposed advanced analysis over the conventional analysis/design approach is demonstrated by application to several space truss problems. The design implications associated with the use of the advanced analysis are discussed.
2. Influence of joint eccentricity and rigidity on the load capacity of a space truss sub-assemblage
Journal of Constructional Steel Research
Volume 1, Issue 4, September 1981, Pages 16-22
Abstract
Experimental testing of bolted and welded space truss sub-assemblages with large joint eccentricities has displayed satisfactory performance. Tests have been carried out on five sub-assemblages from a double layer (plate-like) space truss configuration. The distinctive features of the configuration employed were chord member continuity and the resulting large joint eccentricities. The particular layout adopted furnished orthotropic behaviour for stiffness and strength, so two sub-assemblage configurations were adopted. To provide control and comparisons a welded concentrically jointed sub-assemblage was tested in addition to the bolted and welded sub-assemblages. Although the large joint eccentricities reduced sub-assemblages stiffness and peak load capacity, the continuity of chords largely offset these reductions even when bolted joint details were used; for the welded joint cases peak load capacities were at least 50 per cent higher again. The stiffness of such systems is seen to be sensitive to member and joint imperfections, and joint slip.
3. Tubular space trusses with simple and reinforced end-flattened nodes-an overview and experiments
Journal of Constructional Steel Research
Volume 61, Issue 8, August 2005, Pages 1025-1050
Abstract
The use of tubular space frames made of continuous chord members has substantially increased over the last few years. This growth is mainly due to lower fabrication costs and high erection speed associated with these structural systems. The chord members are usually made of cold-formed shapes or tubes. The connection between the chords and diagonal members is commonly made by staking end-flattened diagonal members over the chords linked by a single large diameter bolt. In spite of this fact, the actual structural behaviour of these connections is still not fully understood. This paper describes six full-scale tests performed on spatial structures to investigate their structural response. Based on these experiments, the structural behaviour, up to collapse, of simple eccentric and reinforced eccentric nodes was discussed. A study of structural reinforcements, created to improve the structural load carrying capacity and minimise deflections, is also one of the main foci of the present paper.
1. Advanced analysis and design of spatial structures
Journal of Constructional Steel Research
Volume 42, Issue 1, April 1997, Pages 21-48
Abstract
Modern limit-state design codes are based on limits of structural resistance. To determine the ‘true’ ultimate load-carrying capacity of spatial structures, an advanced analysis method which considers the interaction of actual behaviour of individual members with that of the structure is required. In the present work, a large-displacement inelastic analysis technique has been adopted to compute the maximum strength of spatial structures considering both member and structure instability. The actual behaviour of individual members in a spatial structure is depicted in the form of an inelastic strut model considering member initial imperfections as ‘enlarged’ out-of-straightness. The maximum strength of the strut is computed based on a member with ‘equivalent out-of-straightness’ so as to achieve the specification's strength for an axially loaded column. The results obtained by the strut model are shown to agree well with those determined using plastic-zone analysis. The nonlinear equilibrium equations resulting from geometrical and material nonlinearities are solved using an incremental-iterative numerical scheme based on generalised displacement control method. The effectiveness of the proposed advanced analysis over the conventional analysis/design approach is demonstrated by application to several space truss problems. The design implications associated with the use of the advanced analysis are discussed.
2. Influence of joint eccentricity and rigidity on the load capacity of a space truss sub-assemblage
Journal of Constructional Steel Research
Volume 1, Issue 4, September 1981, Pages 16-22
Abstract
Experimental testing of bolted and welded space truss sub-assemblages with large joint eccentricities has displayed satisfactory performance. Tests have been carried out on five sub-assemblages from a double layer (plate-like) space truss configuration. The distinctive features of the configuration employed were chord member continuity and the resulting large joint eccentricities. The particular layout adopted furnished orthotropic behaviour for stiffness and strength, so two sub-assemblage configurations were adopted. To provide control and comparisons a welded concentrically jointed sub-assemblage was tested in addition to the bolted and welded sub-assemblages. Although the large joint eccentricities reduced sub-assemblages stiffness and peak load capacity, the continuity of chords largely offset these reductions even when bolted joint details were used; for the welded joint cases peak load capacities were at least 50 per cent higher again. The stiffness of such systems is seen to be sensitive to member and joint imperfections, and joint slip.
3. Tubular space trusses with simple and reinforced end-flattened nodes-an overview and experiments
Journal of Constructional Steel Research
Volume 61, Issue 8, August 2005, Pages 1025-1050
Abstract
The use of tubular space frames made of continuous chord members has substantially increased over the last few years. This growth is mainly due to lower fabrication costs and high erection speed associated with these structural systems. The chord members are usually made of cold-formed shapes or tubes. The connection between the chords and diagonal members is commonly made by staking end-flattened diagonal members over the chords linked by a single large diameter bolt. In spite of this fact, the actual structural behaviour of these connections is still not fully understood. This paper describes six full-scale tests performed on spatial structures to investigate their structural response. Based on these experiments, the structural behaviour, up to collapse, of simple eccentric and reinforced eccentric nodes was discussed. A study of structural reinforcements, created to improve the structural load carrying capacity and minimise deflections, is also one of the main foci of the present paper.
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