| With the development of our country's bridge construction technology more and more mature, PC continuous girder bridge can be adapted to the longer and longer span. As for long-span PC continuous beam bridge, its 0 block generally has larger volume, which could be seen as a mass concrete structure. And most long-span PC continuous beam bridges use high strength concrete, 0 block's casting heat effect become a unignorable problem.With 0 block finishing casting, the internal prestressed channel is formed, densely distributed prestressed channel run through the entire 0 block. For box girder section, the existence of channel has weakened the box girder section, changing the symmetry of plane and the stress characteristics of box girder cross section. Stress concentration phenomenon appears around the hole, which is bad to cross section. This paper takes this as a starting point and regards the fourth main bridge of Shenlong and LongFang main bridge as the engineering background, using the ANSYS finite element software to simulate 0 block casting construction and researching the 0 block which contain prestressed channel under the effect of hydration heat around the hole, and other components temperature field and temperature stress distribution and fracture analysis. The fourth days after placemen, the obvious stress concentration phenomenon appeared in the end of the section of the cantilever end of the 0 block and The principal tensile stress is larger than the tensile strength at the corresponding age, It's easy to appear temperature crack.This article also analyze the parameter factors of 0 block of hydration heat temperature field and temperature stress, and puts forward the corresponding prevention and control measures. |
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