Study On Thermal Effects Of Concrete ARCH Bridge With CFST Stiffened Skeleton

Due to extra long span and high stiffness, the temperature effects of concrete arch bridge with CFST stiffened skeleton is enormous. Under the influence of sunshine or cold temperature, the tensile stress of the main arch ring is liable to exceed the maximum tensile strength of concrete, which would cause cracking. The current China Railway Code for computing temperature loads and temperature effects is not perfect. Independent study is needed especially for special bridges.A field test about temperature was launched on the Beipanjiang Bridge in Guizhou Province. Through collecting and analyzing temperature field data on typical cross-section in each season, the temperature distribution patterns along the arch cross-section depth, width, and thickness direction of the concrete slab were proposed. Then based on the principle of heat transfer and utilization of solar energy and other related theory, the heat exchange system of arch ring was established and the boundary conditions of temperature field were calculated. By using software ANSYS, the two-dimensional temperature field finite element model of the arch ring cross-section was established. Parameters of the finite element model were corrected through comparing the computed results and the tested results. Then, the most dangerous temperature distribution during specified period was figured out and compared with some countries’codes through using the corrected model. After computing the most dangerous temperature field, the plane-strain model and the 3-D model of the whole bridge were built up. Using indirect coupling method, the most dangerous plane thermal stress and longitudinal direction stress of the whole bridge was computed and some advice was proposed to deal with the most dangerous stress.Finally, the influence of stiffened skeleton to the most dangerous stress and deformation of the arch ring was figured out. The evidence confirmed that the stiffened skeleton can reduce the most dangerous longitudinal direction compression stress and the principal tensile stress.