Three-Dimensional Stochastic Traffic–Bridge-Coupled Vibration Analysis Considering Combined Wind-Wave Action

The three-dimensional stochastic vehicle–bridge coupled vibration model is developed in this study to systematically investigate the combined effects of wind, wave, and stochastic traffic. The stochastic traffic flow is simulated using a mass-spring-damper system, including the five degrees of freedom and the 12[Formula: see text]degrees of freedom. The wind speed data at key nodes of the bridge tower are obtained through on-site measurements to ensure realistic wind loading conditions. The wave action is applied to the bridge substructure in the form of pulsating forces. The vibration response of the bridge is solved by forming coupled vibration equations, where wind, wave and traffic actions are simultaneously introduced into the bridge vibration equations. The dynamic response characteristics of the bridge are analyzed under varying traffic density, wind speed, and wave height to assess their relative influences. The results demonstrate that the bridge’s dynamic response is positively correlated with traffic density, wind speed, and wave height, with traffic density having the most significant impact on bridge vibration. Specifically, under dense traffic conditions, the maximum vertical displacement in the third span of the bridge is found to be 2.47[Formula: see text]times that under sparse traffic conditions. Similarly, the maximum transverse displacement is 1.98[Formula: see text]times that under sparse traffic conditions.