Parametric Study of Double Layer Grid Braced Barrel Vault Truss with respect to Various Span to Height Ratios

Abstract

Double layer braced barrel vault is one of the oldest spatial structures. It consists of an upper and lower layer connected to each other by a bracing element.The use of this type of barrel vault improves the rigidity of the vault structure and provides structural systems of great potential, capable of having spans of over 100m. Due to high static indeterminacy it is di cult to analyze these type of structures so nite element analysis software STAAD.Pro is used for the analysis of structure. In initial part of work four types of geometries of double layer braced barrel vault trusses are modeled and their behaviour is studied by comparing axial force and de ection for top layer from which sqaure on square geometry is suggested as best geometry.T he double layer braced barrel vaults of 60m constant span and di er- ent span to height ratios - 2, 3, 4 and 5 having depth of module 2m are analyzed and designed by considering e ect of dead load, live load and wind load. The parameters considered for study are maximum nodal de ection, axial forces and weight of structure. For design of barrel vault truss Indian standard steel pipe sections are used. All the cases of span to height ratios are analyzed and designed for all bottom nodes supported, alternate bottom nodes supported, every third bottom node supported and results are compared from which span to height ratio 5 with all bottom nodes supported is suggested as best geometry.