Influence of floating bridge motion and wind loads on bus users’ ride comfort and motion sickness

Bus users (drivers and passengers) are exposed to vibrations during a journey. Vibration exposure can cause motion sickness, impair ride comfort, and even impact health. Road roughness is the primary source of vehicle vibration. Combined with floating bridge motions, wind loads and high vehicle speeds, the negative vibrational effects can be intensified. This paper investigates the influence of Bjørnafjorden floating bridge motions and wind excitations on bus users' ride comfort and motion sickness for several weather storm conditions. A 13-degree-of-freedom (DOF) intercity bus model with a driver and three passengers was defined for this analysis. The results showed that wind excitations and storm conditions severity significantly affect vehicle velocities at which ISO 2631/1997 ride comfort limits ( a little uncomfortable and fairly uncomfortable ) are reached. The passenger in the middle of the bus feels the most comfortable whereas the passenger in the rear part of the bus the least comfortable. The highest value of motion sickness incidence for every user is achieved for the lowest bus speed of 36 km/h due to the longest time of vibrational exposure. Among users, the driver is the most likely to feel motion sickness on a floating bridge due to his suspended seat. • Vertical vibration intensity increases with vehicle velocity and storms' severity for every bus user. • Wind excitations insignificantly influence vertical vibration from bus users' seats. • Wind excitations considerably influence lateral, yaw, and roll accelerations acting on bus users' bodies from their seats. • Wind load on a bus has an insignificant influence on MSDVz. • Among bus users, the driver is the most likely to feel motion sickness on the floating bridge.