Aerodynamic behavior of a cable-stayed bridge section composed by inclined parallel decks

The understanding of bridge aerodynamic behavior for specific cases with more than one deck is of great importance for structural design. The resultant interference effects caused by one or more windward decks are difficult to predict as they may reduce or increase resultant forces and displacements in leeward decks. This paper presents an experimental study on the transversal response to wind loads of a bridge sectional model with parallel decks. Wind tunnel tests were performed to identify static and dynamic behaviours for different interference scenarios and other additional tests were performed with single deck cases. Results indicated protection when decks were horizontally aligned and amplification as well as reduction of aerodynamic coefficients for decks in different vertical positions. Finally, a conclusive discussion is presented identifying possible reasons for the increases and reductions observed in interference cases.