| Shrinkage and creep are the inherent time-dependent characters of concrete which belongs to a viscoelastic material.It is important to accurately estimate and predicate the deformation and long-term deflection of which arise from the effect of shrinkage and creep for engineering design,quality control and construction process.Long-span continuous rigid frame bridges with high piers are sensitive to shrinkage and creep,especially at different times pouring Of the 0 # block.Large error with respect to the predication of shrinkage and creep would lead to some difficulty of connection for segmental,cast-in-place concrete cantliver bridges and lead to deterioration of serviceability problems,aesthetics and eventually early reconstruction of the bridges.So,it is necessary to study the large volume,high-box-girder section of the internal forces pouring impact.Through the forgoing research work,the major findings are as follows:1.Based on extensive newly investigation finding and much literature at home and abroad,and refered to the progress in concrete constituent mechanics analysis,the nature,mechanics performance under non-axial stress of shrinkage and creep are presented profoundly.Then the influence of activity admixture,reinforcement ratio of conventional bars,prestressed tendons and cylic load on shrinkage and creep are analyzed.Subsequently nonlinear creep damage model under limit state analysis is expatiated due to increasingly paying attention to nonlinear creep effect in civil engineering field.2.In view of many new predication models abroad,which were deduced by large-scale experimental data and fitted by computerized optimization,this thesis presents explicit analysis to them.And compared with the model of new version JTG code(D62-2004),then their precision and applicability are represented respectively.3.By ANSYS secondary development tools,used ANSYS parameters of the language(ANSYS Parametric Design Language) the establishment of the Chongqing Yangtze River Bridge Yudong box girder 0 # block part of the three-dimensional model. With the large number of numerical analysis,based on monitoring of the construction of the test data,and three-dimensional analysis of the results were compared to the box girder 0 block cross-section of three-dimensional distribution of stress in-depth study. Especially by simulating different shrinkage and creep norms to study the sub-section of the pouring of the force of the impact,analysis and trying to grasp at the casting of the box girder section of the force. |
