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Recently, the utilization of cold-formed steel (CFS) roof truss systems and different types of other combination structural support systems, such as concrete or hot-rolled steel support, becomes more frequently used. This paper aims to identify the load transfer characteristics of three different design details for cold-formed truss to supporting system connections and to propose simplified modelling approach for practices.

Simplification modelling of connection design could be proposed for practical purpose based on the load transfer characteristics obtained from detailed study using finite element method. A cold-formed roof truss system with connection is modelled using line elements. However, the supporting system is not modelled in this work. Three types of connection involve, which are five pieces of CFS L-angle brackets, one-piece of CFS L-angle brackets and three types of bolts connection are modelled.

The results of analysis show that the connections located on the loaded side experienced higher reactions than those far from loaded side. From the result, it is also found that the option of “Fixed But” support condition in STAAD.Pro with translational degree of freedom being restrained is the most suitable way to represent the CFS L-angle brackets design for Type 1 connection for use in truss modelled using line elements.

Such increase in usage necessitates an appropriate connection detailing depending on the behaviour of the connection.

This paper aims to present the results of a study on the behaviour of a pre-stressed cable steel truss exposed to fire under fire conditions, basing on the results of a large programme of experimental tests.

The research investigated the deformation and stress change on a pre-stressed steel cable, including the deflection and displacements at different joints and fire behaviour of the pre-stressed steel cable. In other words, the structural behaviours at different loaded pre-stress, the vertical loading, steel cable height, truss dimension and the final temperature were compared in case of fire.

The results showed that the strain of longitudinal chord was far larger than those of the transverse chords, the strains of lower chords were significantly larger than those of the upper chords, strain of the chord near the longitudinal centreline were also larger than those of the outside transverse chords. During heating, the displacement and strain gradually changed from linear to nonlinear with loading, and the yielded chord had also in an order those chords which were at mid-span and near to the longitudinal centreline, yielded at first.

Temperatures in the furnace and at several points of the pre-stressed cable steel truss, as well as deformations, deflections and the stress changes of upper chord and the bottom steel cable and the change of displacement at different joint were measured to achieve those goals and, consequently, to assess the deformation behaviours and temperature of the pre-stressed steel cable.

The purpose of this paper is to present an automated method for complicated truss structure subassembly identification.

A community-detecting algorithm is introduced and adapted to reach the target. The ratio between oriented bounding boxes of parts is used as the weight to reflect the compact degree of assembly relationships. The authors also propose a method to merge nodes together at cut-vertex in model, by which the solving process could be accelerated.

This method could identify the subassemblies of complex truss structures according to the specific requirements.

This research area is limited to truss structures. This research offers a new method in assembly sequences planning area. It could identify subassemblies in complex truss structures, with which the existing method is not adequate to deal.

This method could facilitate the complex truss structures assembly planning, lower the human errors and reduce the planning time.

The method could inspire general assembly analysis planning.

All authors of this paper confirm that this manuscript is original and has not been submitted or published elsewhere.

This paper aims to present the design optimisation using genetic algorithm (GA) to achieve the highest strength to weight (S/W) ratio, for cold-formed steel residential roof truss.

The GA developed in this research simultaneously optimises roof pitch, truss configurations, joint coordinates and applied loading of typical dual-pitched symmetrical residential roof truss. The residential roof truss was considered with incremental uniform distributed loading, in both gravitational and uplift directions. The structural analyses of trusses were executed in this GA using finite element toolbox. The ultimate strength and serviceability of trusses were checked through the design formulation implemented in GA, according to the Australian standard, AS/NZS 4600 Cold-formed Steel Structures.

An optimum double-Fink roof truss which possess highest S/W ratio using GA was determined, with optimum roof pitch of 15°. The optimised roof truss is suitable for industrial application with its higher S/W ratio and cost-effectiveness. The combined methodology of multi-level optimisation and simultaneous optimisation developed in this research could determine optimum roof truss with consistent S/W ratio, although with huge GA search space.

The sizing of roof truss member is not optimised in this paper. Only single type of cold-formed steel section is used throughout the whole optimisation. The design of truss connection is not considered in this paper. The corresponding connection costs are not included in the proposed optimisation.

The optimum roof truss presented in this paper is suitable for industrial application with higher S/W ratio and lower cost, in either gravitational or uplift loading configurations.

This research demonstrates the approaches in combining multi-level optimisation and simultaneous optimisation to handle large number of variables and hence executed an efficient design optimisation. The GA designed in this research determines the optimum residential roof truss with highest S/W ratio, instead of lightest truss weight in previous studies.

The purpose of this paper is to study the wire and arc additive manufacturing (WAAM) method and path planning algorithm of truss structure parts, to realize the collision-free rapid prototyping of truss structures with complex characteristics.

First, a point-by-point stacking strategy is proposed based on the spot-welding mode of cold metal transfer welding technology. A force analysis model of the droplet is established, which can be used to adjust the posture of the welding torch and solve the collapse problem in the WAAM process of the truss structure. The collision detection model is developed to calculate the interference size between the truss structure and the welding torch, which is used to control the offset of the welding torch. Finally, the ant colony algorithm has been used to optimize the moving path of welding torch between truss with considering the algorithm efficiency and collision avoiding and the efficiency of the algorithm is improved by discretizing the three-dimensional workspace.

A series of experiments were conducted to prove the validity of the proposed methods. The results show that the wire feeding speed, welding speed are the important parameters for controlling the WAAM process of truss parts. The inclination angle of the welding torch has an important influence on the forming quality of the truss.

The force analysis model of truss structure in the WAAM process is established to ensure the forming quality and a collision-free path planning algorithm is proposed to improve forming efficiency.

The purpose of this paper is to discuss the performance of efficient cold-formed steel (CFS) sections in building a truss system. A comparative study was performed comparing trusses built with cold-formed and hot-rolled sections.

Medium-scale specimens were fabricated and tested under monotonic loading. Closed CFS sections (tubular sections) were adopted as compression members of the truss, against the open sections (angle sections) in the hot-rolled steel truss. While as open sections (angle sections) were adopted as tension members in both these cases, the performance assessment was made on the basis of the peak loads carried by the trusses, the vertical deflections and the failure modes exhibited.

The results of this study indicated that the overall strength, strength-to-weight ratio and overall convenience in terms of cost and fabrication, in the CFS truss was better than that of the hot-rolled one. Also, the judicious utilization of steel which has limited reserves can be achieved.

Cold-formed and hot-rolled sections are widely used in the steel structures. There are advantages and disadvantages in using each of these configurations, discussed in this work. The advantages are widely known by the scientific community; however, few studies are developed with the purpose of quantifying the gains of each solution. Thus, this work emerges with great innovation, with regard to the experimental evaluation of the trusses' behavior composed of different structural sections.

Located in the Mid-Atlantic region of the United States, Eastern Truss Company produced trusses used in construction of both large warehouses and custom homes. This case presents the student with the opportunity to analyze the critical factors associated with the decision of whether Eastern should adopt a new production technology and whether cash flows from reduction of temporary workers will cover adoption coasts. The student must evaluate the decision to adopt the production technology through the lens of operations management tools. This case is appropriate for undergraduate business studies in the field of operations management.

Case study.

Undergraduate operations management.

This paper demonstrates the use of genetic algorithms (GAs) for size optimization of trusses. The concept of rebirthing is shown to be considerably effective for problems involving continuous design variables. Some benchmark examples are studied involving 4‐bar, 10‐bar, 64‐bar, 200‐bar and 940‐bar two‐dimensional trusses. Both continuous and discrete variables are considered.

Wavelets are being increasingly used for damage diagnostics. The purpose of this paper is to present an algorithm that uses the wavelet transform for detecting mixed-mode, also known as combined mode, cracks in large truss structures.

The mixed-mode crack is modeled by superposing two damage modes, and this model is combined with a finite element model of the truss. The natural modes of the truss are processed through the wavelet transform and then used to determine the damage location. The influence of multiple parameters such as truss geometry, crack geometry, number of truss members, orientation of truss members, etc. is investigated as part of the study.

The proposed damage detection algorithm is found to be successful in detecting single mode as well as mixed-mode cracks even in the presence of significant end effects, and even when a relatively coarse sampling of natural modes is used. Results from multiple simulations that involve three commonly used truss structures are presented. A correlation between damage severity and the magnitude of wavelet coefficients is observed.

The proposed algorithm is found to be successful in accurately detecting damage, but direct determination of damage severity is found to be challenging.

This paper aims to introduce a method to couple truss finite elements to the material point method (MPM). It presents modeling reinforced material using MPM and describes how to consider the bond behavior between the reinforcement and the continuum.

The embedded approach is used for coupling reinforcement bars with continuum elements. This description is achieved by coupling continuum elements in the background mesh to the reinforcement bars, which are described using truss- finite elements. The coupling is implemented between the truss elements and the continuum elements in the background mesh through bond elements that allow for freely distributed truss elements independent of the continuum element discretization. The bond elements allow for modeling the bond behavior between the reinforcement and the continuum.

The paper introduces a novel method to include the reinforcement bars in the MPM applications. The reinforcement bars can be modeled without any constraints with a bond-slip constitutive model being considered.

As modeling of reinforced materials is required in a wide range of applications, a method to include the reinforcement into the MPM framework is required. The proposed approach allows for modeling reinforced material within MPM applications.