| Popis: |
Rail-cum-road truss bridges are rapidly developing, and frequent cracking in freshly poured deck concrete is of great concern. For the performance of such a load-bearing deck, it is necessary to understand its stress status due to short-term shrinkage. Taking a newly-constructed rail-cum-road truss bridge as the case project, this paper, by ANSYS finite element simulation, mainly analyzed the stress distribution in deck concrete under short-term action of shrinkage. Shrinkage of one deck panel and two companion specimens shortly after the concrete pouring was measured through in- situ testing. It was found that the free shrinkage of companion specimens at 40 days is 140~150 micro strains, significantly higher than that indicated by the current code. Under the action of short- term shrinkage, tensile shrinkage stress in the magnitude of 1,5~3,5 MPa is present in the deck, triggering potential cracking, and its effect shall therefore not be neglected. |
