Numerical linear elastic investigation of steel roof deck diaphragm behaviour accounting for the contribution of non-structural components

Dynamic analysis programs and empirical formulae are often used to compute the period of vibration of single-storey steel buildings. Recent ambient vibration tests of buildings in Quebec and British Columbia have shown that the predicted period of vibration is typically much longer than that measured. Software and empirical formulae do not usually take into account the stiffening effects of the non-structural components; this could be the source of the discrepancy between the results in the field and the results obtained by computational methods.; This research project concentrates on the roof diaphragm system of single-storey steel buildings and the contribution of the non-structural components to diaphragm stiffness. It is believed that the non-structural components, roofing materials such as gypsum board and fibreboard, add to the overall stiffness of the system. A roofing system called AMCQ SBS-34 consisting of gypsum board, ISO insulation board and fibreboard, all hot bitumen adhered, was studied. The full roof system, as well as its individual components and connections, were first studied through laboratory testing. The flexural and shear stiffness of the fibreboard and gypsum panels, as well as the shear stiffness and equivalent flexural stiffness of the complete roof system and shear stiffness of the roofing connections were determined.; Linear elastic finite element models, using the SAP2000 software, were developed to replicate the behaviour of bare sheet steel and clad diaphragm test specimens. The test based properties of the roofing components and connections were incorporated into the definition of the elements. The models were then calibrated based on the results of large-scale diaphragm tests by Yang. Once the elastic behaviour of the diaphragms had been matched, a parametric study was performed in order to assess the importance of the contribution of the roofing assembly relative to the roof deck panel thickness.; It was shown that as the deck thickness increases, the relative contribution of the non-structural components decreases on a percentage basis, but does not become non-negligible. The increase in shear stiffness of the diaphragm ranges from 58.6% for the 0.76 mm deck panel to 4.7% for the 1.51 mm roof deck panel, dependent on the sidelap and deck-to-frame connection configuration.