Research On The Key Technology Of Construction Control For (48+80+80+48)m Continuous Beam Bridge

Recent years,with the development of transportation,prestressed continuous beam bridge is widely used,especially in the application of traveler cantilever construction technology,which makes continuous bridge even more prosper.However,cantilever construction because of the long period of construction,the complex construction technology,and uncertain factor increasing,also makes actual displacement and stress of main girder become more complicated.So it is necessary for this article to research on the key techniques of continuous girder bridge construction control.This paper takes Baoying bridge(48+80+80+48)m 4-span prestressed concrete continuous beam as the research object,and the key technology of construction control was studied,including:(1)According to the construction characteristics of this bridge,the Finite element model of main beam is established by the use of Midas/Civil 2015 bridge engineering software.And the change rule of theoretical deflection and stress is obtained by the simulation of every construction stage.(2)Analyzed the influence factors of main girder construction control from five aspects: concrete bulk density,concrete elastic modulus,prestress loss,concrete shrinkage and creep and closure sequence,and ensured principal parameters and most rational closure sequence.And the variation law of them in the construction process were obtained.By adjusting the parameters,the influence of various factors on the later period deflection of the beam was reduced.(3)According to the design of construction drawings and relevant specifications,the finite element analysis and calculation was conducted by the use of Midas/Civil2015 bridge engineering software,which ensured the safety of temporary structure.(4)The purpose and content of construction control were described,and the main beam alignment and stress control were introduced in detail.Compared and analysed the theoretical values and the measured value of girder cantilever construction stage deflection,bridge alignment,root section stress,1/4 cross sectionstress,stress the bridge section,and obtain the change law of beam shape and stress.The result from the main girder construction control showed that finite element model calculation was rational,and temporary structure was safe.The final closure accuracy control was good,and after finishing the bridge,the linear and stress met the related specifications and design requirements.In addition,the construction control achieve the aim.