Construction Control Of Long Span CFST Stiff Skeleton Arch Bridge

The concrete filled steel tube stiff framework arch bridge owns self erectingconstruction system to divides the weight of the arch ring into many different parts ofconstruction stage,which makes it possible to develop long-span concrete archbridge.With the increasing of the span,the stability of the construction,the concrete’sshrinkage and creep,reasonable construction project become the research focus of thestiff framework arch bridge.Based on domestic and overseas achievement of research and background ofWeishui bridge,this paper sets up the whole construction process of beam slabcombination model with finite element analysis soflware Midas,Using the beamelement to simulate the stiff framework and the tube concrete;using plate element tosimulate the top and botter of box girder,this model coordinates the bearing ofpressure by combined nobe of the plate element and stiff framework elem-ent.Calculating the static force of this mode,and re-anlysis other factors including thestructure deflectiong deformation,pressure stood by composition and stability,thebuilding of the bridge is in line with requirements,no matter in temrs of theconstruction stage or completed stage.Due to the main function of arch bridge is to bear stress,the stability of archbridge becomes the research focus.Based on the integral stability theory,this papercalculate the stability of each construction stage and instability mode of the beginningparts of arch ribe when casting is completed by the load incremental method.Aming at the arch rib construction,this paper also anyalyse optimalitily the verti-cal casting sequence and horizontal casting sequence and horizontal cross ring.Bycomparision and anyalisis the structure deflection,component stress and and stability-y,some useful conclusions are reached,which is much significant for the contructionof bridges.10years after bridge completed,concrete shrinkage and creep is fundamentalcompleted;the pressure of bridge cross section is also re-distributed,the general trendis towards to more reasonable direction.