Abstract:

The features of uneven distribution temperature stress in recently poured  concrete and the effective measures to prevent temperature cracks were studied. The 0＃ box girder in the Weihe Specially Long Bridge located  in the highway from Xi’an to Tongchuan was taken as a research project, which was  computed on  MIDAS／FEA(multitier distributed applications services／finite element analysis)finite analysis element software. The temperature field of hydration heat of the concrete in the construction period was numerically calculated by the finite element method. The effects of three different mechanical control measures of crack control were analyzed. Combined with the results of  temperature detection, the mechanical control measure was optimized.The results showed that the temperature inside the concrete rose to a  peak about 52 hours after the  concrete was poured, with or without cooling water pipes in the box temperature difference of the maximum temperature about 10℃.When the temperature difference between inside and outside of the concrete at 20℃ was a good time to remove the template.Temperature stress was concentrated in the junction web plate and diaphragm of the box girder, thus setting the cooling water pipes could improve the uneven distribution of temperature stress. Compared with other results, the whole process temperature monitoring and the finite element dynamic analysis by this method was better at  optimizing the engineering measures of crack prevention.
 

Key words: temperature monitoring, finite element analysis, temperature field, temperature stress, crack