The bearing capacity of arch cover structures made of thin-walled cold-formed profiles

Introduction. The article is focused on evaluating the stress-strain state of nonreinforced arch cover structures made of thin-walled cold-formed profiles and arch cover structures reinforced by arch frames made of triangular trusses and girders. The relevance of the study is backed by the need to reinforce arch covers in the event that the design area of operation of a structure is different from the actual area of operation, which is confirmed by the recent cases of collapse of these structures. To reduce the labour input into simulation, the authors suggest a 3D modelling methodology presented using the case of a hangar reinforced by orthotropic plates and rods. Materials and methods. A 2D analysis of an arch was performed using the parameters of the reduced cross-section and a 3D analysis of the same arch was performed using a combined cross-section of plates and rods to verify the methodology. The 2D arch and 3D models were subjected to snow loading in compliance with the regulatory document document SP 20.13330.2016 “Loads and impacts”. Parameters of reduced straight sections and stresses, arising in the 2D arch, were analyzed on the basis of identified internal forces and the regulatory document SP 260.1325800.2016 “Thin-walled steel structures made of cold-formed galvanized profiles and corrugated sheets”. A reduction in the rigidity of corrugated sections is taken into account by assessing the rigidity subjected to the effect of a single force. Finite element modeling was conducted in SCAD Office software; stresses and displacements were calculated automatically. Results. The 3D calculation method involving orthotropic plates and rods showed satisfactory convergence with the calculation made in the two-dimensional formulation. Maximum stresses arising in a 3D model are 2 % lower than in a 2D arch, and maximum displacements are 21 % lower thanks to a more accurate FEM analysis of the 3D behaviour of the whole hangar. Conclusions. The proposed modeling technique reduces the labor intensity of structural modeling and is suitable for evaluating the joint behaviour of basic and reinforced structures of any type.