Model for Vertical Hyperthermic Temperature Gradient Distribution in Concrete Box Girder in China

The temperature field of concrete box girder under sunshine is an important factor to be considered in the design of bridge superstructure. Based on the meteorological parameters and the semi-empirical formula given by related bridge specifications, the vertical temperature gradient distribution model of prestressed concrete box girder was established using SPSS software. The amplitude of the temperature gradient model is calculated according to the theory of statistics. The index function model considering wind speed, solar radiation and temperature variation was obtained, and the method to determine the amplitude of vertical temperature gradient was summarized according to different building climate zones in China. The applicable conditions of the model are as follows: sunny and cloudless days with high radiation quantity should be selected; The selected months are generally from May to July, and June in extremely cold regions. It is verified that the calculated value fits well with the measured value by monitoring data of 3 real Bridges in different zones. The model of temperature gradient heating in warm areas was calculated. For the temperate climate regions without real bridge measured data, the recommended value of temperature gradient amplitude in this region is given after trial calculation. It explores the method of using only meteorological data without surveying and mapping, which can save a lot of manpower and material resources.