Analysis Of Shrinkage And Creep Effect Of Concrete For Long-Span Continuous Rigid Frame Bridges

Shrinkage and creep are the inherent time-dependent characteristics of concrete which belongs to a kind of viscoelastic material. For long-span continuous rigid frame bridges, shrinkage and creep of conerete structure have prodigious effeet on bridge alignment and internal forces during bridge construetion. In the mean time, the problems such as prestress loss,bearing asymmetry sink,concrete box-beam deflection,box-beam web crack,structure stress re-distributing and so on,which cause bridge structure invalidation or lose function early while it works. For these reasons, accurate estimation and predication of the deformation and long-term deflection of long-span bridges which arise from the effect of shrinkage and creep is of high importance for engineering design,quality control and construetion process.Take the Hanjiang bridge for engineering background in this paper, is completed mainly in order to go off work make:(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. Have analysed influence concrete contract the major factor that changes slowly,trade off study concrete have representative change pattern slowly. and have summarized concrete to contract the basically theoretical.calculation method that changes calculation slowly.(2) This article combined with the actual date,the model analysis results of CEB-FIP(1990),ACI(209),JTGD62-2004 and JTJ023-85, optimize and forecast the concrete creep which occurred on the prestressed box beam. The result indicated that use the JTJ023-85 model the computed results combined well with the actual ones.(3) Using MIDAS/Civil procedure make finite element analysis the impact of shrinkage and creep of concrete on the continuous steel bridge was used sumed up from the aspects of main beam deformation, cross-section stress, prestressing loss, pier top moment, and carry out theoretical calculation.