Past earthquakes, such as the L'Aquila 2009 and Emilia 2012 events, were characterised by a strong combination of horizontal and vertical components of seismic acceleration, which highlighted the vulnerability of long-span precast structures. Nevertheless, the common design practice neglects the effect of the vertical component, despite the current codes prescribe specific checks for horizontal prestressed and long-span members. This is typically done with simplified linear calculations based on simply supported uncoupled members. This study addresses the seismic performance of various configurations of 25 m wing-shaped roof element and I-shaped beam, representative of a typical long-span deck for modern precast industrial buildings.Linear and non-linear analyses were carried out considering both uncoupled and coupled roof decks, encompassing Linear Static Analysis (LSA), Natural Frequency Analysis (NFA), Spectral Response Analysis (SRA), and Non-linear Time-History Analysis (NLTHA).The comparison between different coupled and uncoupled configurations revealed critical insights into the realistic behaviour of long span precast elements under vertical seismic loading. The analysis of the data collected allowed also to critically assess the current design methodologies, shading light over potential improvements.