Effective and Fine Analysis for Temperature Effect of Bridges in Natural Environments

In this paper, an effective simulation technology was proposed for finely predicting the temperature effect of bridges. Based on the ray tracing method, a three-dimensional (3D) sunlight-sheltering algorithm was developed to predict the temperature field more precisely. To improve the computational efficiency, the substructure method was applied in mechanical or coupled thermomechanical analysis. The effects of wind speed, atmospheric environment, and thermal properties of ground surface were also included. The proposed technology was verified by comparing the measured data (temperature on a rigid-frame concrete bridge) with the predicted values and was applied to analyze the seasonal temperature effect of a cable-stayed bridge thoroughly. In the analysis, a girder-pylon-cable system was finely established, and nonuniform distribution of temperature and stress were shown as well. The results show that the maximum thermal stress was 30 MPa on the steel girder in summer, and the deflection reached a maximum value of 22 mm. Moreover, the different effect of heat flux intensity received by horizontal and vertical surfaces was identified. Also, temperature variations in cables were found to play a significant role in the vertical and longitudinal deformation. As a result the computing time was saved up to 83%, and this study provided a comprehensive reference for designs of bridges. (C) 2017 American Society of Civil Engineers.