Research On CFST Arch Bridge Swivel Construction Control

In order to better adapt to the undulating terrain of mountains,and meet the constraintsunder the bridge,many spaning bridges are usually built by the method of rotationconstruction.The rotation construction generally uses the structure itself and steel as therotational facilities,the slideway with a smaller coefficient of friction and reasonable rotarystructure,at the same time,simple traction equipments are taken by the structure.It makes use ofboth sides of the terrain and the prefabricated bridge structures are assembled by simplebrackets.At last,the whole completes rotation by a certain angle.Compared with otherconstruction methods,the rotation can save construction timber,and reduce the equipmentquantity effectively.Meanwhile,the construction could be finished rapidly and safely.Of whichthe most prominent is that the construction process has a litter effect on the underbridgestructure,by directly across the adverse topography.In this paper,the study on rotationconstruction technology is based on the engineering background of Nanping Minjiang RoadNo.1bridge.And the conclusion may become reference for the design and calculations ofsimilar concrete-filled steel tube(CFST) arch bridge constructed by rotation method.(1) According to the specific engineering of Minjiang Road No.1bridge,the model ofrotation hinge is built by ANSYS finite element software. From the calculation results,we canconclude that compared with the stage before spin, the stress of each parts of the rotation hingein the swivel increases with limited increment.The finite increment is caused by the use of planeharp structure,that the friction coefficient of the contact pair only0.06.The analysis of the localentities model from MIDAS/Civil software reveals that the maximum stress of the temporarysteel towel presents to the junction with the back wall.In the swivel stage,the force and stress ofarch rib are small,the same as the deformation.By means of the collection of materialparameters on site,we can calculate theoretical center of gravity. The calculation of rotationtraction force needs to consider two cases,the center support and the jointly support of thecenter and circuit.(2) Minjiang Road No.1bridge is a CFST arch bridge constructed by rotation method.Thesecurity and stability of each component should be ensured in the swivel process.For the sake ofsmoothly approaching,the elevation of final closure needs to be strictly controlled.Therefore,theadoption of construction monitoring is necessary.The monitoring result shows that,the elevationdifference near the final closure between theoretical and measured value within1cm,and thestress monitored results of arch rib are consistent with the finite element model.Before formal swivel,the detail weighing project should be made.Since the plan harp is adopted by thebridge,the balance weighing project is different from the spherical hinge,in which the appliedload position should be transformed.(3) MIDAS/Civil finite element software is adopted for establishing member model offull-bridge.The model and standard are used to calculate the component and whole structurecalculation in ultimate limit state and the deflection and stress of arch rib in serviceability limitstate.The results meet standard requirements.Meanwhile, the suspender cable force detectionand static and dynamic load test in completion state,proves that the detection results isconsistent with theoretical calculations,and meets the design requirements.