Temperature monitoring and analysis of a long-span cable-stayed bridge during construction period

The temperature induced response of long-span cable-stayed bridge in cantilever state is significant, which is of great interest to study the temperature characteristics during construction period. A method of analyzing the eigenvalue and its extremum of daily temperature based on cubic spline function (CSF) is proposed. By setting the fixed time interval reasonably, introducing variable time interval and extracting nodes at the MinMax of daily temperature, the obtained CSF can approach the measured temperature curve with high accuracy. Based on CSF, the temperature characteristics at three levels of measuring point, section and component are analyzed in turn. The temperature monitoring data of a cable-stayed bridge with main span of 938 m and side span of steel-concrete composited box girder (CBG) during construction are analyzed. The results show that the temperature variation of steel box girder is remarkable; the steel beam of CBG is similar to steel box girder before composited, and it turns stable after composited; the influence of PE color on cable temperature is notable than that of the cable specification; as blue PE cable, the temperature difference of cable vs pylon and cable vs CBG exceed 17 degrees C and 13 degrees C.