Study On Temperature Change Characteristic Of Concrete Bridge Towers’ Existing Vertical Cracks

In recent years,Cable-stayed bridge and suspension bridge in the use of concrete bridge towers, there are many cracks in the process of the cracks are mainly vertical cracks, cause the cracking of concrete bridge towers in a lot of factors, the tower wall temperature difference between inside and outside surface is an important influencing factors. Scholars to do a lot of research work in bridge concrete cracks and temperature effect, put forward a series of concrete cracks and the calculation method of temperature stress, but in the cracks and temperature effect of concrete bridge towers is still no a set of complete theoretical reference for practical engineering, there are still some worthy for further study.This article through to one bridge on the temperature field and the fracture monitoring, and combined with the detailed analysis of the finite element model, the space temperature field distribution of concrete bridge towers, crack distribution and morphology and its influencing factors, such as crack repair measures to compare the detailed research. The main contents include:1. This paper discussed the distribution of temperature field in concrete Bridges at home and abroad, the research situation of temperature stress and crack, put forward the shortcomings existing in the research and the blank, expound the relevant theories of fracture mechanics and temperature effect.2. Based on one bridge tower as engineering background, extended closed state distribution of temperature field and crack width of concrete tower in the two season with the change of temperature was observed, the change rule of temperature field with time was analyed.3. Established 3 d entity model of bridge tower, the spatial stress field in the simulation analysis of the concrete bridge towers, the bridge tower structure stress distribution along the section height direction were studied.4. Based on the theory of fracture mechanics and the temperature effect, combined with Midas Fea finite element analysis software to establish the existence of cracks in the concrete pylon tower block model, changed the width of the crack under different temperature load for stability analysis. Analysis summarized under the condition of temperature changing regularity of change surface vertical crack width.5. A discussion was carried on about the reasons of concrete bridge tower surface vertical cracks, and from two process of bridge formation including design and construction, a series of measures of crack prevention were given. Finally according to the different degree of cracking of crack, provides corresponding repairing methods.