Analysis And Study On The Coupling Effect Of Concrete Box Girder Of Damp Heat

Temperature load and humidity load is caused by a very important reason for the concrete surface cracking:the temperature stress of concrete in early has received wide attention in engineering field, but the wet load of concrete has been ignored for a long time been neglected, research progress is very slow, the calculation of humidity stress still remains on the empirical formula and evaluation phase structure; simulation calculation of temperature load stress due to not buy considering the effect of humidity on the heat conduction, is not complete, the need for further complement and perfection.In fact, heat conduction within the concrete are coupled, the temperature stress and humidity stress calculations need to consider the impact of coupling effect, this paper adopts the linear and nonlinear coupling heat conduction equation, thus obtains the consideration of coupling effects of concrete temperature field and humidity field, stress field, and lay the foundation for the concrete structure the next step of the computation; and through the COMSOL software platform, the theory of the coupling can be achieved, compared with the previous experimental data obtained by the numerical test, the reliability of this method is verified; On the basis, the concrete moisture heat coupling effect were calculated, and the results were compared with the calculated before, and before the method of anastomosis; then write one dimensional coupled moisture and heat conduction by using the software of MATLAB M file, heat conduction model of concrete will be further Jane prior to one-dimensional model; finally, through comparative analysis of four groups of calculation conditions and a concrete side wall coupled heat and moisture transfer engineering examples, the study obtained the stress characteristics of temperature field, humidity field, heat load caused by concrete, as well as the influence of coupled heat and moisture stress, in order to prevent concrete due to the effect of moisture heat coupling effect caused by the cracking and provide some basis and reference. Analysis based on the above calculation, this paper obtained the following conclusions:?moisture deformation is mainly embodied in the dry shrinkage of concrete, the temperature conduction conduction process is concerned much more slowly; dry shrinkage stress will gradually increase to concrete at under the situation of continuous drying, thereby causing the cracking of concrete.?the temperature conduction process is more rapid; temperature difference influence depth is larger also, after deep inside the conduction to the concrete can be after a period of time; and the temperature stress is also very fast, the stress development speed of conduction velocity of temperature effect.?under different temperature and humidity conduction velocity is different, thus affecting the development of dry shrinkage stress of concrete; but the temperature conduction under different humidity is almost no gap, the humidity field is mainly through the moisture migration (water evaporation) change to take away the heat to the impact of temperature field, the negligible effect on the temperature field of concrete conduction almost.