Papers by Author: Dong Po He

Abstract: The commercially available finite element program ANSYS was used to model the refrozen process of the bored pile. The effects of the refrozen process by casting temperature of concrete, heat of concrete hydration and air convention were analyzed. To estimate the time when the bearing capacity of the bored pile is formed, the finish time of refrozen process was determined by modeling the whole refrozen process of the bored pile. The calculated results are in good agreement with experimental data. The analysis shows that the refrozen process is related with the casting temperature of concrete. The higher the casting temperature is, the more time the refrozen process takes.

Abstract: The temperature distribution and strains due to heat of hydration of cement in a concrete box girder were measured on site during construction of the Harbin Songpu Bridge. The lateral and vertical temperature distributions and stresses in webs and slabs were analyzed. The study of the measured results shows that there are large temperature differences in the box-girder sections, and both the lateral and vertical temperature distributions and stresses are nonlinear. In some parts of the sections, the tensile stresses are even greater than the characteristic value of concrete tensile strength.