Stability And Structure Characteristics Of High Pier Large Span Continuous Rigid Frame Bridge During The Symmetric Construction Stage

The high pier and long-span continuous rigid frame bridge with the advantages ofsimple construction、reasonable force、economical cost,has been widely used indomestic bridge construction.For continuous rigid frame bridge built in the mountainvalley area,due to the landform limit,side span ratio have to be different from theordinary bridge,which makes the continuous rigid frame bridge with cantilever castingconstruction must based on symmetrical cantilever pouring on the remaining singlecantilever beam.Sichuan Ganzi Dadu River Bridge is a typical asymmetric construction ofcontinuous rigid frame bridge,in side span closure after cross side single cantileverpouring in as many as five block, the construction process of the Dadu River Bridge asthe research object,aiming at the problems in the construction process are studied andanalyzed:①Using plane analysis software Midas to establish the asymmetric cantileverpouring、symmetrical cantilever construction stage model of finite element analysis,thetwo kinds of construction methods in the force difference should be the constructionstage, and to analyze the force of asymmetric cantilever construction stage,found thatthe force with single cantilever pouring segment length increases approximately linearlydecreases.②The analysis of cantilever construction stage in the spatial finite elementsoftware ANSYS using zero initial location method with tangent position installationmethod,and compared with the results of plane bar system finite element softwareMidas,the feasibility and accuracy verification.And the establishment of phase spacesimulation model of Dadu River bridge construction installation method using the zeroposition, according to the analysis of shear lag effect in the construction stage,the shearlag effect changes with the construction stage,and the largest single cantileverbridge,double cantilever construction stage of spatial stress analysis.③Analysis of construction of asymmetric pouring the Dadu River Bridge in the whole process of elastic stability:the asymmetry、 symmetrical cantilever pouringconstruction of cantilever construction,comparative analysis of value stable featureconstruction stage,asymmetry found step cantilever pouring construction of cantileverwhen the single feature structure stable value,this phenomenon makes the structure ofone order、two order stability characteristics compared with the symmetrical cantileverpouring are improved.④Study on the stability of the largest cantilever state: the wind load、constructionprocess of the hanging basket、 falling load segment self weight、 constructionloads,considering four possible loading conditions.On the bridge at the longestcantilever,cantilever construction stage of elastic stability and considering the nonlinearbuckling analysis of geometrical and material nonlinearity,the stability characteristics ofthe above four kinds of load conditions and the value of load coefficient,evaluate thestability of the bridge in construction to the largest single cantilever、double cantileverstage,can provide a reference for practical engineering.