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.

Numerical studies on the wind characteristics over gorge and valley terrains are very rare. Some simplified gorge terrains with different included angles and different terrain heights were adopted in the present study in order to obtain the basic information about the wind characteristics. To ensure the accuracy of the numerical results before conducting the actual numerical simulations, a new form of turbulence kinetic energy profile to serve as an inlet boundary condition was proposed based on the SST k-ω turbulence model. Then, the wind characteristics – including the mean wind speeds, turbulence intensities and mean square deviations – of the turbulent flow in the gorge terrain were studied for different included angles and different terrain heights. The results showed that the larger the included angle of the gorge terrain, the more significantly the mean wind speeds at the gorge center increase. The mean square deviation values of the turbulent flow at the gorge center are much smaller than those at the inlet. The effects of the terrain height on wind characteristics such as the mean wind speed and turbulence intensity at the gorge center are very small. The research conclusions can provide a point of reference for the wind characteristics over real gorge terrain and the simulation method of the current study can provide a new idea for other numerical simulations.

Wind tunnel test and computational fluid dynamics simulation were conducted to study the wind characteristics at a bridge site in mountainous terrain. The upstream terrains were classified into three types: open terrain, open terrain with a steep slope close to the bridge, and open terrain with a ridge close to the bridge. Results obtained from the two methods were compared, including mean speed profiles in the vertical direction and variations of wind speed and angle of attack along the bridge deck. In addition, turbulence intensities at the bridge site obtained from wind tunnel test were discussed. For mean speed profiles in the vertical direction, two methods are reasonably close for open terrain, while mountain shielding effects are evident for open terrain with a steep slope for both the methods, but the extents of effects appear different. Wind speed and angle of attack along the bridge deck are mainly influenced by the local terrain. Strong downslope wind is generated at the lee slope for the case of wind normal to top of the ridge. The comparative results are expected to provide useful references for the study of wind characteristics in mountainous terrain in the future.

Box girders are aerodynamically favorable, and the paper presents a study on the vortex-induced vibration (VIV) of this girder type at large angles of attack. Taking a box girder as an example, the form of the guardrails and the position of the maintenance tracks were improved to increase the VIV performance. The aerodynamic mechanism was further investigated according to the change in flow field around the girder. Results showed that the VIV performance of the box girder at positive angles of attack is worse. Improving secondary elements is an effective way to increase the VIV performance. Adding four rectangle bars above the original guardrails could achieve the target by preventing the generation of the vortex and blocking its movement. Moving the maintenance tracks inwards with a reasonable distance could also achieve the target as the flow passes through the girder more smoothly. With the combination of the optimal form of the guardrails and the optimal position of the maintenance tracks, the VIV performance of the bridge is higher. The countermeasures provide reference for the inhibition of the VIV of box girders.