Analysis Of Temperature Gradient For Concrete Box Girder Bridges In Severe Cold Regions

With the research of the temperature effect of bridge by the domestic and foreign scholars,problems of the bridge temperature stress in bridge design and construction is due to increasingly known. Many practical engineering and research results show that the temperature distribution in the sunshine on the concrete box girder temperature stress has a great influence, using different modes of sunshine temperature gradient calculated temperature stress vary greatly. At present different countries, different regio ns of the solar temperature gradient mode concrete box girder bridge has a different understanding, for example, the US division of the American norm for four climate zones, each zone has a different climate temperature gradient model to guide the design a nd construction. China’s vast territory, climate vary widely, but the bridge specification follows the temperature gradient mode only two areas of the United States, specifies a set temperature gradient mode, in the future there is still large room for imp rovement. Therefore it is necessary to experiment and theoretical analysis, exploration and research for prestressed concrete bridge sunshine temperature distribution and temperature gradient mode different regions of C hina, in order to guide the engineering design and construction.This paper focuses on the temperature gradient mode Ordos region of exploration and research, based on a region of Inner Mongolia Erdos continuous rigid frame bridge construction monitoring work, at home and abroad while the concrete temperature distribution and temperature gradient existing research results, based on in-depth understanding of Sunshine concrete box girder temperature distribution and temperature gradient mode, clear sunshine concrete box girder temperature distribution and its temperature gradient study, and problems in order to determine the location of the scene temperature measurement points, found a box girder under the action of sunlight temperature distribution, and summed up the temperature distribution of box girder, obtained the most unfavorable time of day the temperature field, thereby fitting box girder as most unfavorable temperature gradient mode foundation. Based on the experimental analysis of the real temperature of the bridge, through the inner box girder embedded temperature sensor for continuous box girder temperature field observations and records to obtain data on the box girder temperature field. Analysis of the temperature at different locations in box girder on the basis of the measured data, according to a series of parameter values actual local weather conditions, the thermal properties of concrete material, shape box girder calculated by using a combination of heat conduction in the form of finite element program the box girder in the local solar radiation temperature field strength conditions, draw box girders sunshine and temperature distribution with the measured values were compared to verify the correctness of finite element program box girder temperature distribution. By combining theoretical data with the measured data can be made more clear box girder temperature distribution sunshine temperature field.In the calculation of the measured temperature and condition of temperature field, temperature gradient mode with reference to d ifferent provisions of the national bridge specification, combined with sunshine temperature field of concrete box girder influencing factors and conclusions concrete box girder temperature effect, consider the bridge their geographic latitude different, strength of solar radiation, atmospheric temperature by fitting suitable for the actual situation of the local large span concrete box girder vertical temperature gradient. C hinese specification temperature gradient model is actually a model for the United States followed the norm, but the US specification is divided in four different regions of the United States to guide the bridge construction and construction. China and the United States are not the same climate, but the country only with a temperature gradient mode, so in the future there is still much room for improvement. This article provides a temperature gradient mode Ordos region, by contrast, was fitted with a temperature gradient analysis for this area.