Experimental Study on the Effect of Attachments on the Vortex-Induced Vibration of a Centrally Slotted Box Deck

Centrally slotted box decks have been commonly used as components of bridges, especially for long-span bridges. A wind tunnel experiment was conducted to investigate the effect of attachments on the vortex-induced vibration (VIV) of the deck. In this research, the characteristics of VIV responses at different attack wind angles of 5 models considering naked bridge decks, crash barriers, wind barriers, and vehicles on bridges were studied and discussed. The effects of crash barriers, wind barriers and vehicles on the VIV behaviors of the bridge deck were also investigated experimentally. Multiple lock-in wind speed intervals were found to occur for all the models considered, and the vibrating amplitude and frequency show differences in different models. The results of the study showed that, owing to the installation of crash barriers or wind barriers, the vibrating frequency at the second lock-in interval indicated a double natural frequency. However, for the naked bridge deck model, the vibrating frequencies were close to the vertical natural frequency at all lock-in regions. Additionally, the frequency showed an evolutionary characteristic from the first lock-in interval to the second lock-in interval. Generally, the installation of crash barriers and wind barriers caused an increase of 89.8% and 123.7% on maximum vibrating amplitudes respectively. The vehicles had amplification effects on the amplitudes in both lock-in regions, with an increase of 41.5% at the maximum amplitudes. This study provides a guideline for designing bridges consisting of centrally slotted box-type decks.