Study On Effect Creep And Shrinkage Of RC Arch Bridge Utilizing Combined Construction Method

Many long-span reinforced concrete arch bridges were constructed by method of cable hoisting or stiff skeleton in china.Cable hoisting method can reduce the segmental lifting weight,but there are more than the problems of the number of joints and poor integrity.Mthod of Steel skeleton exist big problem of steel large,long construction time, the late creep and shrinkage.People construct RC.arch bridge by method of cantilever or combined construction method of cantilever casting and stiff skeleton abroad since the last century since the 1960 s. arch have overall good and appearance.Reinforced concrete arch bridge which constructing by combined construction method,constructing skewback section by cantilever casting,valut shut by stiff skeleton, then around stiff skeleton wrapped concrect, and ultimately formating reinforced concrete arch bridge.Concrete.shrinkage and creep have a great impact on deformation and force of compressive main arch.So far the country has not been theoretical studies on effcotion of shrinking and creep of reinforced concrete arch bridge by combined construction method of cantilever casting and stiff skeleton.Paper relies Guizhou Province Department of Transportation projects, " key technologies of large span concrete arch bridge are constructed by combined construction method of cantilever casting and stiff skeleton",To span 210 meters of Guizhou Province Yelang Lake Bridge as the research object,adopting numerical analysis method,studing Shrinkage and creep have an effect on deformation and force of mian arch ring of arch bridges ultilizing combined construction method of cantilever casting and stiff skeleton:①Collecting domestic and foreign research data of concrete shrinkage and creep, representative prediction model of shrinkage and creep 、 creep theory and various predictive models were analyzed.summaring method of shrinkage and creep used finite element analysis.②Using MIDAS/CIVIL finite element software,using D62-2004 model, GL2000 model,NCHRP496 model,carry Yelang Lake Bridge main arch shrinkage and creep analysis,Comparing the law of main arch deformations and stress redistribution which calculated for three models in the construction process and completed bridge.Discussing the effect on creep and shringkage for main arch ring force and deformation under the different length cintracton for cantilever casting section and stiff skeleton.③By theoretical analysis of D62-2004,GL2000,NCHRP496 model on shrinkage and creep effect,giving the camber value of Yelang Lake Bridge main arch ring under the three models, the analysis showed that camber distribution by skewback thrust influence line is close to camber curve fiting function.