The Large Concrete Hydration Heat Temperature Effects Research of the Cable Stayed Bridge
|Keywords||large-span cable-stayed bridge pile cap cable tower box girder temperature effect finite element simulation|
With the rapid development of our transportation, large number of Long-span concrete bridges have been built, many problems occurred in procedure of bridge construction, The temperature rift problem caused by temperature stress is more especially pronounced, therefore the problem of long-span concrete bridge in temperature field peculiarity and the temperature effect caused by them should be paid attention to by bridge researchers, taking Jiujiang Yangtze River bridge as the engineering background, this paper analysis the temperature field and temperature stress characteristic of South Pylon pile cap, north cable tower, lower beam, concrete box girder, the main work are as follows:(1) Calculating the parameters according to the basis of the heat of hydration design conditions obtained from the practical project; establishing the simulation computational model of temperature field caused by heat of hydration in the pile cap concreting process by the finite element analysis software MIDAS, then the theoretical result will be compared with experimental results and analysis will be made to the temperature controls of the bridge pile cap in the current project and furthermore the analysis of cooling effect caused by the diameter of cooling water pipe and the distance between the adjacent water and other parameters.(2) Establishing the simulation computational model of hydration heat temperature field from the north and south cable tower under tower column and the lower separator of south cable tower. Through the calculation the conclusions can be drawed with the temperature effects caused by the hydration heat temperature field from those concrete structures when they were being poured, Look for the dangerous regions with huge temperature stress and make some positive proposals to the actual project.(3) Establishing the simulation computational models of temperature field caused by hydration heat of the concrete box girder, considering the characteristic of concrete box girder temperature stress by the influence of different convection coefficient. analysis the temperature effects of the current conditions by comparison with the measured data, Optimizing the construction by considering the three different conditions:the first condition is pouring 15 meters box girder concrete in one step, the second condition is pouring 15m twice and 7.5m for each time; the third condition is pouring 15 meters box girder concrete with one step, but pouring the soleplate blast nozzle and ventral shield first, then pouring the crest slab 10days later. The temperature stress of concrete box girder in the three working conditions will be calculated and compared with the former one, and the best condition than before will be established.