ABSTRACT
Previous research studied the influence of the diaphragm effect on the behaviour of pitched roof portal frames, having Z purlins and corrugated sheeting as cladding. Research results emphasized the stabilizing effect on portal frames by taking into account the lateral constraints ensured by a typical cladding system -Z purlins with one layer of sheeting panels. Further studies are focusing to extend the knowledge on different cladding systems. Present study is dedicated for roofing system with Z purlins and sandwich panels. The purpose of the paper is to simulate in 3D portal frame models with the stabilizing effect given by sandwich panel covering. In the proposed methodology the diaphragm stiffness of the sandwich panels was determined analytically, in order to create an equivalent plate diaphragm, which could be implemented in the 3D structural model. The simulations show clearly the effect of the roof diaphragm on the lateral stiffness increase of the internal frames, which can affect the design of the frame components or the integrity of the cladding system.
