To accurately predict buffeting-induced stresses in a long-span cable-stayed bridge with a twin-box deck, buffeting analyses should take into account the cross-sectional distribution of both aerodynamic and aeroelastic forces over the surface of the bridge deck. They should also be performed on an accurate multi-scale model rather than a spine-beam model of the bridge. This paper proposes a framework for stress-level buffeting analysis of a long-span cable-stayed bridge with a twin-box deck under distributed wind loads. Methods to obtain distributed aerodynamic and aeroelastic forces on the bridge deck are introduced. The proposed framework synthesizes the buffeting analysis with distributed wind loads and the multi-scale modelling and model updating of long-span bridges. The proposed framework is applied to the Stonecutters cable-stayed bridge in Hong Kong. The responses computed using the proposed buffeting analysis framework are compared with those computed using the sectional-force based traditional method on a spine-beam model. The comparative results show significant differences in stress distribution on the twin-box deck and the multi-scale model yields larger maximum stress responses compared with the spine beam model. (C) 2016 Elsevier Ltd. All rights reserved.