Research On The Temperature Field And Its Stress In The Insulating Concrete Pavement Girder Bridges

The concrete bridges in the external environment,not only withstand its own weight and the moving load,but also suffer from the solar radiation and ambient temperature change effect. According to the current design code of highway and bridge,in some concrete bridges, the stress caused by the temperature gradient is close to or even greater than that caused by the moving load. In order to resist the temperature stress, a large number of prestressed steel or common steel are needed. Based on the research background, this paper puts forward a method of using thermal insulation concrete as concrete bridge pavment.By reducing the thermal conductivity of the pavment layer, the temperature gradient values get down, thus the temperature stress of the main box girder is reduced, which can greatly reduce the project cost.In this paper,based on heat transfer,solar physics,thermal elasticity theory and structural analysis theory,with numerical simulation and theoretical derivation,a research on the temperature field and its stress with insulating concrete pavment is given, which can reveal characteristics and its influence on structural behavior of the temperature field and its stress of concrete box girder bridge with thermal insulation concrete pavement characteristics,which provides the theoretical basis for design of this kind of bridge. In this paper, the main work and research results are as follows:(1)A 3* 28 m continuous box girder bridge is acted as the research object.By means of finite element analysis software ANSYS,a 3D model is established including the thermal insulation concrete pavement and concrete girder.On the basis of verifing the feasibility and accuracy of the numerical model,a sensitivity analysis of the temperature field of box girder with insulating concrete pavment girder is given,to determine how to choose these parameter values is best.The results show that the thermal insulation layer parameters only have a significant impact on the roof's temperature field,having little impact on other parts.Through the parameter comparison,a conclusion is established that 10cm insulating layer thickness have the biggest impact on the roof temperature field distribution and temperature gradient along the height direction.(2) Basing on the above analysis and numerical simulation data,the temperature gradient modes is entrenched suiting for insulating concrete pavment.And suggestions are put forward that the applicability of the temperature gradient. (3)A sensitivity analysis of the temperature stress with insulating concrete pavment girder is given,to determine how to choose these parameter values is best.To determine how to choose these parameter values is best.The results show that the thermal insulation layer parameters changes have a great influence on box girder transverse and longitudinal temperature stress. When the insulation layer thickness to 10 cm,coefficient of thermal conductivity is 0.3 W/(m · K), a significantly improvement on the stress of main girder can be found.(4) To further study the social and economic benefits of thermal insulation of concrete pavement layer,and to improve the stress state of bridge structure and the economic benefit, using a 3* 28 m continuous box girder bridge as an example, and focus on economic contrast, making prospect to its application prospect.