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Vortex-induced vibrations (VIVs) have been frequently observed on long-span bridges (LSBs) in recent years. Unlike other destructive aerodynamic phenomena of LSBs, VIVs are self-limited in amplitude, primarily affecting the serviceability of LSBs through unpleasant users' feelings characterized by human body vibration. Most existing studies discussed this issue based on a popular human body vibration measure, the human comfort index (HCI) in ISO 2631-1. However, the HCI is primarily concerned with vibration above 0.5 Hz, which might be unsuitable for disclosing the influence of VIV because of the low-frequency features of LSBs' VIVs. To address this limitation, this study advocates using the motion sickness index (MSI) to revisit the serviceability of LSBs experiencing VIVs based on an innovative wind-traffic-bridge simulation platform. Different from current studies exclusively focusing on vehicle riders, this paper additionally incorporates a vibration model for standing persons to understand the feelings of the pedestrians on the bridge. On this basis, the influence of VIV and traffic load is comprehensively examined. The results indicate that the HCI is inappropriate for exploring the serviceability of LSBs under VIVs regarding users' feelings, but the MSI is a good alternative. Moreover, the increasing traffic load can obviously mitigate the adverse effect of VIVs on the bridge's serviceability, which may be utilized to control VIVs of LSBs in real-world engineering practice. [ABSTRACT FROM AUTHOR]

Affected by many factors, the local wind environment on the bridge deck is complex and changeable, and it seriously threatens traffic safety. To accurately evaluate the wind field on the bridge deck, this paper develops a system to monitor the actual local wind environment and applies it to field measurement of the wind parameters at different positions of a complex truss girder bridge. The results show that the wind parameters on the bridge deck, including wind speed, gust factor, and turbulence intensity, are different from the bridge site due to the influence of the ancillary facilities. Also, the wind profile of the local wind field on the bridge deck is more in line with the polynomial distribution, which makes the equivalent height of the wind load much higher than the vehicle gravity. It should be noted that the measured power spectrum of the bridge deck is quite different from the wind spectrum applicable to the bridge site area, so it is not appropriate to use the wind spectrum of the bridge site area to carry out the analysis of the windmill bridge, and a more suitable wind spectrum for bridge deck wind field is proposed. [ABSTRACT FROM AUTHOR]

Bridges located in deep reservoir are exposed to threats from near-fault ground motions. The resilience and economic loss of a highway bridge in deep reservoir under near-fault ground motions require better understanding. This study incorporated the existing resilience and economic loss assessment framework with the effect of post-earthquake underwater repair. The methodology was illustrated to evaluate the seismic performance of an example highway continuous rigid-frame bridge in deep reservoir. The three-dimensional nonlinear numerical model of the example bridge was built with the hydrodynamic added mass estimated by the fluid-structure interaction model. Two types of near-fault ground motions, the forward-directivity and fling-step ground motions, were selected to conduct the nonlinear seismic analyses of the bridge. The fragilities of the piers, bearings, and the bridge system were assessed and resilience and economic loss of the example bridge under different types of near-fault ground motions were evaluated and compared. It can be concluded from the studies that: (1) the peak ground velocity (PGV) is suggested to be taken as the intensity measures of ground motions for the probabilistic seismic demand models of the bridge in deep reservoir; (2) the fling-step ground motions caused larger pier, bearing, and system damage probability, but lower resilience and bigger economic loss than the forward-directivity ground motions; (3) the structural resilience decreases, whereas the economic loss increases with the increasing water level; and (4) the highest water level and the fling-step ground motions result in the worst performance of the example highway bridges in deep reservoir near active faults. The framework not only aids engineers to better understand the seismic performance, but also assists in the decision-making of post-event rehabilitation activities for the highway bridges in deep reservoir. [ABSTRACT FROM AUTHOR]

Vehicle–bridge coupling vibration is a complicated interaction process, which includes multibody dynamics of vehicles, structural dynamics of bridges, and wheel–rail contact relationships. A single software is not adequate for the coupling analysis. Therefore, to efficiently conduct the vehicle–bridge coupling vibration analysis, an interactive method that integrates the commercial finite element software ANSYS and the multibody system software SIMPACK was presented in this study. The method takes advantage of the high modeling efficiency of ANSYS and the powerful wheel–rail analysis ability of SIMPACK. Two interactive methods, the dummy body coupling method and the equivalent flexible track method, were presented, and the merits and demerits of the two methods were compared in detail. Finally, the equivalent flexible track method was adopted for the analysis. The interactive method that was presented was confirmed to be feasible by the continuous bridge example, and the simulation for the long-span bridge was discussed further. It is shown that the interactive method has high computational efficiency and good convergence rate for various bridges, and the vehicle–bridge coupling vibration analysis can be conducted well and followed conveniently by other researchers. [ABSTRACT FROM AUTHOR]