Fine analysis for non-uniform temperature field and effect of railway truss suspension bridge under solar radiation

In this study, a new method is proposed to simulate the non-uniform temperature field and its effects of truss suspension railway bridge under solar radiation. This method is adopted to calculate the non-uniform temperature field based on the sunlight coefficient derived from bounding box detection and sunlight shadow analysis. By taking the node temperature obtained from the thermal analysis as the boundary condition, the deformation of suspension bridge caused by the non-uniform temperature is calculated. Taking truss suspension road-rail bridges as an application example, the accuracy of the proposed method is verified through the health monitoring system and the on-site test data. The results indicate that the temperature field of truss suspension bridge is periodic and non-uniform, and the sunlight shadow cannot be ignored in the thermal analysis. It is also found that the short-term ambient temperature effect of truss suspension bridge is mainly caused by solar radiation and daily temperature variation, which generates a non-uniform temperature field. The overall temperature change of structure caused by seasonal temperature changes is the primary cause for long-term ambient temperature effect. The girder temperature-induced deflections considering non-uniform temperature distributions are significantly different from the results obtained from the temperature load model which is used to define the overall rising or falling of structure temperature. The research methods and conclusions of this study can provide valuable references for maintaining the alignment of truss suspension railway bridges during construction and operation.