Temperature Gradient And Effect Analysis Of Large Span Continuous Rigid Frame Bridge Based On Probability Statistics

The development trend of continuous rigid-frame bridge is high-pier and large-span, and the temperature gradient has great influence on deformation and stress of this type bridge in particular. There are a lot of experiments and research about temperature field, however, the temperature gradient is not the most adverse temperature gradient because those experimental research of temperature limited to a few days observation. Based on a large number of measured data of the background of a long-span continuous rigid frame bridge in Shanxi Province, the article found the time-varying regularity by selecting the second and the fourth block as the experimental object. And the time-varying regularity originates from long-term monitoring in the middle section in the change of sunshine warm up and sunset cooling. The paper finally determines the most adverse positive and negative temperature gradient mode of Shanxi Province. And analyzed the influence of different forms of temperature gradient on continuous rigid frame bridge.The main contents of the paper are as follows:(1) Introduced the temperature load calculation theory and the theory of probability and statistics analysis, which is the analysis basis of the box girder temperature field and temperature gradient mode.(2) In order to research the concrete temperature field characteristics in Shanxi Province, we have made a long-term experiment of a bridge and collected a large number of the temperature experimental data. Box girder temperature measuring point layout scheme are introduced and the box girder roof and bottom temperature measuring point data are analysed The article summarizes the regular of various parts of the temperature gradient distribution and time varying influence.(3) In order to research the effect of different temperature gradient on the bridge, this paper introduced in detail the rules of the temperature gradient of both at home and abroad and analyzes the experimental data by using probability and statistics. And found that Maximum plus or minus temperature difference obey the generalized extreme value distribution each part of the box girder.Calculated the The negative temperature gradient curve Along vertical and the width of the web directions of the box girder with 50-year return period. Calculated the he worst negative temperature gradient modes of web plates ceiling and the floor of box beam.Analyzed and studied the positive and maximum temperature difference in Box beam ceiling, web boards and backplanes,and found there exists Linear relation between the three, and fitting the relationships between the three;(4)Introduced the finite element theory of calculating the temperature field and thermal stresses.Introduced the three-dimensional finite element model of bridge and two-dimensional finite element model.Calculated and analyzed the measured temperature and design temperature specification system under the action of temperature effect of the whole bridge. Bridge under temperature gradient is calculated and analyzed the whole theory of the temperature effect. Calculated and analyzed the different temperature stress of box girder under temperature gradient distribution; Calculated and analyzed the different temperature stress of box girder under negative temperature gradient distribution.