Influence of Asphalt Pavement Conditions on Fatigue Damage of Orthotropic Steel Decks: Parametric Analysis

The function of asphalt pavement on orthotropic steel decks (OSDs) is to transmit and disperse the concentrated wheel loading to the bridge structure and to strengthen the local stiffness of the OSD. Fatigue damage in deck-to-rib joints of OSDs is directly related to the asphalt pavement conditions: Road surface roughness affects vehicle loads on the bridge, resulting in significant effects on the stress levels in the joints of the bridge. The temperature also has a significant influence on the performance of asphalt pavement on OSDs, affecting the stress levels and hence the accumulation of fatigue damage. An investigation of the influence of asphalt pavement conditions on the fatigue damage of deck-to-rib joints in OSDs and a three-dimensional bridge–vehicle model, including the pavement, is presented in this paper. A simplified method to model the pavement effect was verified. The dynamic responses calculated from the bridge–vehicle coupled model were compared with the structural health monitoring (SHM) data measured from a real cable-stayed bridge to validate the accuracy of the dynamic response analysis. Parametric analysis considering different temperatures, road roughness conditions, and moving vehicle speeds was conducted. The fatigue damage analysis results demonstrate that temperature and roughness are two significant factors affecting the fatigue performance of OSDs. Several recommendations and conclusions are proposed based on the parametric study results.