6. Optimal Design of Double-Layer Barrel Vault Space Structures

Barrel vaults are given different names depending on the way their surface is formed. The earlier types of barrel vaults were constructed as single-layer structures. Nowadays, with the increase of the spans, double-layer systems are often preferred. While the members of single-layer barrel vaults are mainly under the action of flexural moments, those of double-layer barrel vaults are almost exclusively under the action of axial forces and the elimination of bending moments leads to a full utilization of strength of all the elements. Double layer barrel vaults are generally statically indeterminate. In such systems, due to the rigidity, the risk of instability can almost be eliminated. The use of this type of barrel vaults enhances the stiffness of the vault structure and provides structural systems of great potential, capable of having spans in excess of 100 m. In this chapter, three double-layer barrel roof structures are optimized to investigate the performance of the CBO, ECBO, VPS and MDVC-UVPS meta-heuristic algorithms. The structures are subjected to stress, stability and displacement limitations according to the provisions of AISC-ASD. The design variables are the cross-sectional areas of the bar elements which are selected from a list of steel pipe sections.