Optimal design of a large-span arched structure

Introduction. Large-span structures are designed as entertainment and mass-use buildings, sports facilities, etc. A steel arched structure can be used as a covering for large-span structures. The issue of the rational design of large-span steel arches, as well as the proper choice of the structural design and the analysis of its bearing capacity is relevant. Materials and methods. The covering of a tennis sports facility with the span of 108 m, that represents a double-hinged steel arch without tightening, arches with prestressed tightening and several lattice options are considered. The cross-section of structural elements was selected; the effect of prestressing on forces and displacements in the arch, as well as the amount of metal per structure were analyzed. The general stability of these arched structures was analyzed. Calculations were performed in the geometrically nonlinear formulation using the LIRA-SAPR software package. Results. It is determined that the weight of the arch, including the tightening and the lattice is smaller than the weight of the arch without the tightening. The amount of metal, used to make columns, can be reduced to simplify structural units due to the absence of gusset transfer from the arch with tightening to columns. The required prestressing value is set for the tightening to ensure the required rigidity of the arch. Several methods were used to determine the critical load at which the arch loses its stability in its plane: the analytical method, geometrically nonlinear calculation results, and the Stability mode implemented in LIRA-SAPR software package were employed. The critical load turned out to be higher for the arch with tightening. Conclusions. Following the above computations, a decision was made to use a double-hinged arch with prestressed tightening and a lattice as the covering of the sports facility. The values of the critical load that triggers the arch stability loss, obtained using the geometrical nonlinear finite-element analysis and the Stability mode, were quite close. Application of the analytical method resulted in an overestimated value of the critical load, which prevents it from being recommended for use.