Wu Xiaoguang,He Pan,He Qilong,Feng Yu
Abstract:
In order to establish the measured temperature gradient field of continuous box girder bridges in different areas of Shaanxi Province, three representative continuous girder bridges in northern Shaanxi, central Shaanxi and southern Shaanxi were selected for one year continuous observation. By fitting the measured temperature data, three temperature gradient models have been established. The results show that the vertical maximum temperature difference of continuous box girder bridge in three areas in Shaanxi Province is different. According to the specifications set concrete pavement, the maximum temperature of northern region is 18.6℃, the maximum temperature of central Shaanxi is 21.2℃, the maximum temperature of southern Shaanxi is 22.9℃, but were less than the standard value of 25℃. Different from the normative provisions, the measured data show that there is vertical temperature difference in the bottom plate of the box girder, the maximum positive and negative temperature differences of the bottom plate in the three regions were 3.5℃ (-3.1℃), 2.8℃ (-2.9℃) and 1.5℃ (-1.5℃). Based on the measured temperature gradient, the finite element model of the box girder closure section was established, and the measured temperature effect was analysed. The results showed that in the positive temperature gradient , without considering the vertical temperature gradient effect of the bottom plate, it is partial safety; in the negative temperature gradient, not taking into account the effect of vertical temperature gradient of the bottom plate, the force would have a negative impact for bottom plate, impartial security. It is suggested that the vertical temperature gradient of the bottom plate should be considered comprehensively in the design checking of continuous (rigid frame) box girder bridge