A semi-empirical model for vortex-induced vertical forces on a twin-box deck under turbulent wind flow

Q. Zhu, You Lin Xu, L. D. Zhu, B. Y. Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

28 Citations (Scopus)


Large-amplitude VIV can cause fatigue damage accumulation in structural components and reduce safety and comfort levels of road vehicles, trains, and pedestrians. Therefore, in the design of long-span bridges with twin-box decks, it is essential to know vortex-induced forces (VIF) and predict vortex-induced responses (VIR). Currently, there are several semi-empirical models for the estimation of VIF but most of them are established based on measured VIR for single-box decks and without considering turbulent wind effects. This paper presents a semi-empirical model for vertical VIF on a twin-box deck with and without turbulent wind flow. First, the two existing semi-empirical single-degree-of-freedom (SDOF) VIF models are discussed, and a refined SDOF model for VIF under smooth wind flow is proposed. The proposed SDOF VIF model includes all the non-conservative motion-induced force terms. An approximate analytical solution for the maximum amplitude of VIR is then deduced based on the proposed VIF model. Second, based on quasi-static assumption, the proposed VIF model is further extended to take account of turbulence wind effects by introducing a turbulence-induced positive damping term into the model. Finally, the validity of the proposed VIF model with and without turbulent wind effects is examined using a newly-developed wind tunnel test technique for an elastically-mounted twin-box section model. The comparative results show that the proposed VIF model can effectively predict the maximum VIR of a twin-box deck under different turbulent fields with different structural damping ratios. It is also found that the maximum VIR decreases nonlinearly with the increase of turbulence intensity.
Original languageEnglish
Pages (from-to)183-198
Number of pages16
JournalJournal of Fluids and Structures
Publication statusPublished - 1 May 2017


  • Turbulence effect
  • Twin-box deck
  • Vortex-induced force model
  • Vortex-induced vibration

ASJC Scopus subject areas

  • Mechanical Engineering


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