Static Stability Analysis Of Railway Long-Span Arch Bridge With Stife Skeleton Considering Construction Process

The concrete arch bridge with stiff skeleton shares many merits with CFTS arch bridge and the concrete arch bridge. The most noticeable advantage is that the self-spanning system accelerates the construction process and paves the way for constructing a long-span arch bridge. According to the contents the thesis is constituted of two parts:The first part presentsareview of thehistoryand the present development ofconcrete arch bridge with stiff skeleton,introducestheconceptand classificationofthestability of archbridge,and generalizestheresearchstatus ontheconeretearchbridgewithstiffskeleton, and proposes thatit’s very important to analyze the stability of concrete arch bridge with stiff skeleton at the constructionstage.Then introduces the basic concept and theory of the in-Plane buekling and theLateralbuckling of arch-structure whicharethetwoinstabilityformsinarchbridge, and are alsothe critieal loadformulasindifferenttypesofarch. In addition, the thesis briefly introduces thefiniteelementmethodused to analyse the stability of archbridge.The second part, takes the beipanjiang long-span arch bridge as an example, establelishes the element comcuptional model with MIDAS/CILVIL analysis software. Not only the static mechanical behavior and the stability of the construction stage is studied, but also the factors affecting the stability at the completion stage are analysized, based on which the following conclusions are obtained:Firstly, in a given construction program, the lowest stability factor occurs in web casting stage, soclose attention should be paid to the issue of the stability of the structure during the web casting phase.Thebuckle cable force has large impact on the stability of the steel skeleton during erection stage.Once the steel skeleton is closed, the buckle cable force has little effect on the bridge. However, it should be noted that it has great influence on internal force and linear of the bridge. The Buckling stability factor of the bridge is greater than 4 throughout the construction stage, and the writer points out that the bridge is in a secure situation during the construction stage. The Geometric nonlinearity is under little impact from force in the completion stage, which could be ignored.Secondly,wide span ratio,temperature load, the upper structure rigidity, fixed bearing seating position, thereduction of the core concrete’s stiffness and other factors can exert effect on the stability of the bridge. For this bridge,the effect of wide span ratio on this bridge is the most remarkable factor. In the condition that the wide-span ratio is constant,the width distribution of the chamber has little effect on the stability of a bridge. The effect of chamber width distribution on the stability varies according to the wide-span ratio variation.And the width distribution of the chamber depends upon the stability of structure in construction.Nevertheless. The finding shows that temperature, the upper structure rigidity, fixed bearing seating position, and the reduction of the core concrete’s stiffness has no obvious effect on the bridge.