The spatial distribution of unsteady loading due to gusts on bridge decks

The spatial distribution of the dynamic loading due to gusts on line-like structures is generally assumed to be similar to the spatial distribution of the oncoming gusts. This is known as the strip assumption and it has been a key element in Davenportʹs solution to the problem of buffeting of long-span bridges, allowing for the development of a complete methodology of assessment of wind actions. Experiments in model and full scale, and theoretical analysis using lifting-surface theory have provided a clearer picture of the spatial distribution of the gust loading on bridge decks. These have helped define the limits of the strip assumption and have provided an empirical model of the gust loading for closed-box girder bridge decks. The limits of the strip assumption for stationary bridge decks are discussed in the paper and a description of the spatial distribution of the gust loading is proposed.