Analysis On Sensitive Parameters To Arch Ring Under Cantilever Casting Construction Of Reinforced Concrete Arch Bridge With Single Cell Box

Cantilever casting method is a common method for construction of long-span reinforced concrete arch bridges abroad.In recent years,more than ten reinforced concrete arch bridges have been built or are under construction with cantilever casting method in China.The span of the bridge has been renovated to 240 m,which indicates that the design theory and construction technology of cantilever casting arch bridges in China have become more and more mature.Construction control plays an important role in the suspension casting construction of arch bridges.Reasonable control of structural parameters can minimize the construction error of each parameter and achieve a reasonable completion state,which makes the parameter sensitivity study and parameter identification of arch bridges with cantilever casting method particularly important.In this paper,based on the Yelanghu Bridge,the sensitivity parameters of reinforced concrete arch bridge with single cell box constructed by suspension casting are analyzed.The main work is as follows.(1)Through the improved stress balance method,the cable forces satisfying the crosssection stress and alignment of the arch ring of the Yelanghu Bridge are calculated,and the variation laws of the cross-section stress,alignment,cable force and buckle tower deviation in the construction process are analyzed.(2)Around the problems of construction error in construction control of suspension cast-in-place arch bridge,the sensitivity of parameters to arch ring oversize,initial tension of cable,rigidity of main arch ring,rigidity of cable,rigidity of pier and buckling tower,temperature difference between cable and arch,long-term temperature difference,shortterm temperature difference and shrinkage and creep of concrete are studied,and the influence of parameters change on arch ring alignment and stress,cable stress and buckling tower deviation is studied,sensitive parameters are determined.(3)Specific regulations on temperature gradient of suspension cast-in-place arch bridge are not given in the industry code.in the short-term temperature sensitivity analysis,the mechanism of heat transfer between the main arch ring and the external environment is studied through the cross-disciplinary theoretical analysis of heat transfer,physics and astronomy,and the response model of sunshine temperature during the construction of the main arch ring of the Yelanghu Bridge is established.The distribution of positive temperature gradient and negative temperature gradient in the main arch ring section of concrete arch bridge with single cell box during suspension casting construction is studied.A gradient temperature distribution model for suspension casting of arch ring is proposed.(4)With the help of the experience of artificial neural network theory in the construction control of cable-stayed bridge and continuous rigid frame bridge,the artificial neural network theory is extended to the construction control of long-span cantilevered reinforced concrete arch bridge,and the application research of BP neural network in the construction control of cantilevered arch bridge is carried out for the first time.