Effect of wind barriers on the aeroelastic instabilities of a hinged-deck cross-section cable-stayed bridge

Abstract

The main idea of a hinged-deck cross-section cable-stayed bridge appears with the need of increasing the capacity of a simple bridge by adding to lateral extension decks to the main deck. An experimental wind tunnel campaign to analyse the aeroelastic behaviour of a hinged-deck cross-section cable-stayed bridge has been performed. The bridge cross-section under study is formed by three parts: a central deck and two lateral extension decks joined to the central one using hinges and supported by their respective cable systems. The experimental model used is a reduced 6 degrees of freedom (DOFs) model for the elastic problem, which has previously proved to give good results concerning the bridge behaviour. The number of DOFs induces a new complexity in the oscillating motion of the bridge deck, compared to classical single deck 2 DOFs configurations.In this work, the aeroelastic tests performed at the UPM/IDR ACLA-16 wind tunnel facility to address the effect of wind barriers on the aeroelastic characteristics of the bridge section are reported. Nominal barriers are considered and compared with the case with no barriers. The effect of barrier porosity (wind barriers of the central deck and lateral decks) is also analysed. Stability ranges are reported in terms of reduced wind speed. The results show the large influence of the barriers in controlling the aeroelastic characteristics of the bridge. In some configurations, a large increase in bridge stability has been found due to the relevant effect of the barriers in changing the flow around the bridge.