Temperature behavior of cable-stayed bridges. Part II - temperature actions by using unified analysis

The temperature action of long-span cable-stayed bridges is complicated because of the high indeterminacy of their structure. Previous studies on the temperature behavior of bridges were either limited by finite sensors, failing to capture the accurate relation between the temperature field and temperature-induced responses, or constrained to a "divide-and-conquer" strategy, requiring considerable manual intervention and regarded as computationally inefficient. This study develops a unified approach to the investigation of thermal behaviors of cable-stayed bridges by integrating the heat-transfer analysis and structural analysis based on the same refined global 3D finite element model. The companion paper (Part I) investigates the temperature distribution, while this paper (Part II) focuses on temperature-induced responses. The temperature distribution data is automatically converted to thermal loads, and thermal elements are changed to structural elements to calculate the temperature-induced responses of the bridge. Results show that the effect of the temperature variation of cables is nonnegligible and should be taken into account during the structural analysis. The longitudinal displacement of the girder and the longitudinal displacement of the tower top are mainly influenced by the average girder temperature, the mid-span deflection and the cable stress are dominated by the cable temperature and average girder temperature, and the stress of the girder is controlled by the vertical temperature difference. The ratio of the thermal stress to the dead load stress of the girder can reach 96%. The calculated displacement and stress of the bridge agree well with the corresponding measurements, consequently verifying the effectiveness of the proposed unified approach to calculating temperature-induced responses.