Analysis Study On Zero Block Of Box Girder Temperature Field And Thermal Stress

With the improvement of strength of concrete and the prestressed technologydevelopment, the span of the prestressed concrete continuous girder bridge by the cantilevercast-in-place piecewise built construction methods is becoming larger and larger. Thehigh-strength concrete will produce a lot of hydration heat with the concrete pouring andcuring early, and the hydration heat will form the complex temperature fields. The complextemperature fields will emerge temperature stress of the formation of the concrete what resultthe crack of the concrete structure on non load.The bearing capacity and the service life of theconcrete structure will be impacted that not be ignored. Therefore, Analysis study on Zeroblock of box girder Temperature field and Thermal stress has practical significance.In this article，The author Put forward the research questions and research backgroundand Introduced the research progress both at home and abroad under the premise that refer tothe relevant data. The author summarized the cement hydration heat effect on the temperaturefield and temperature stress of the type and characteristics and introduces the calculationmethod of concrete temperature field and temperature stress. From the concrete hydrationtemperature field and the related calculation method of argument, The author studies the zeroblock of box girder that is the largest size section casting temperature field characteristics andthe early preliminary calculation of temperature stress in project-the bridge of Hanjiangriver as the engineering background with using ANSYS finite element software. The authormake a simple summary on prevention and control measures of temperature cracks andfracture remedy and put forward on temperature control measures of the quantitativeassessment.Thesis research shows that heat of hydration of the zero block rapid accumulation in theprocess of concrete pouring.The base plate and the bottom of web plate partition is the key ofthe temperature control what size are bigger and the internal temperature is the highest. Earlyconcrete will produce temperature crack because the big difference between internal andexternal temperature.The difference between internal and external hydration heat temperatureand shrinkage of concrete will make redundant constraint of zero block and lead large tensilestress to be produced. Based on the space finite element analysis, the work obtains some useful conclusions and is expected to provide reference in optimum design of zero blockand anti-cracking.