Combined experimental-numerical study on vortex-induced vibrations of curved cable-stayed bridge: Effects of superelevation and spatial curvature

The vortex-induced vibrations (VIVs) of curved cable-stayed bridges differ from those of straight bridges due to two key factors. First, the superelevation introduces deck asymmetry and alters the effective angle of attack, leading to mechanisms responsible for VIVs that remain unclear. Second, spatial curvature modifies wind yaw angles and induces coupled vertical-torsional VIVs, complicating the mode shape correlation factor (MSCF) and making it challenging to assess VIVs solely from a straight sectional model. Investigating these effects through wind tunnel tests (WTTs) requires costly multiple sectional models, while fluid-structure interaction (FSI) simulations of in-service decks demand high computational burdens due to the fine mesh required for modeling barrier configurations. In this study, the effects of superelevation are investigated by combining sectional models, WTTs, and FSI simulations using two-dimensional (2D) unsteady Reynolds-averaged Navier-Stokes (URANS) and three-dimensional (3D) improved delayed detached eddy simulation (IDDES). Zero-thickness baffles are employed to model the barriers and accelerate simulations. Furthermore, the spatial curvature effects and MSCF are clarified by comparing sectional and full curved model WTTs. Results show that 2D URANS overestimates VIVs due to the inability to capture inner recirculation regions on the deck's lower surface, while 3D IDDES agree well with WTTs. Superelevation has unfavorable effects on VIVs by generating strong secondary vortices downstream of the central barrier at certain yaw angles, leading to conditions that might increase VIV amplitudes with respect to standard decks. The MSCF of 1.28 is recommended for coupled vertical-torsional VIVs, providing practical guidance for evaluating curved bridge VIVs using simplified sectional models.