Contral And Study The Creep Effect Of High-Speed Railway Prestressed Concrete Continuous Box Girder

It is important to accurately estimate and predicate the deformation and long-term deflection of high-speed railway bridges from the effect of creep for construction process. To set pre-eamber properly is the guarantee that the structure of bridge could reach perfect linearity expected under the course of construction and force by vehicles, after upwards and downwards again and again.Firstly, there are many theories about concrete creep, the calculation models are different which based on different influencing factors. Based on the past research findings, this paper explains detailed the concrete creep mechanism, the effect factors, the calculation theories and methods. And then, a comparative analysis of several for predictive models commonly used at home and abroad for creep mechanism are taken into account, including the scope, the advantages and disadvantages for the actual structure.Secondly, creep various factors of C50and C60that used by current express railway are analyzed quantitatively. By analysing and comparing predictive precision of every models, the predictive model which was fit for elevation supervision and control of bridges was developed. And then calculating creep effect for two different simple beams by using the finite element analysis software Midas/Civil, it reveals that the calculated results agree well with practical results.Finally, according to the supervision and control scheme, the three steps elevations about moving form traveller, placing concrete and prestressing wires of steel were measured and controlled. The elevation supervision and control of the Beijing-Shanghai express railway bridge on Qinhuai new river indicated that the precision of GL2000、ACI and04model is good, which can meet the needs of precision demands, and the conclusion in this paper can be used in construction control of the long-span continuous bridges.