Research On Key Technology Of Alignment Control Of Single Pylon Cable-Stayed Bridge With Universal Hinge

The special-shaped cable-stayed bridge with universal hinge and single tower is a new type of cable-stayed bridge structure adopted for the first time.Compared with the common floating system,semi floating system,tower beam consolidation system and rigid frame system cable-stayed bridge,the cables are arranged asymmetrically in space,and the spatial effect is obvious.The tower will produce large displacement along the bridge and across the bridge,and even torsion effect around the tower.As a result,it is more difficult to control the shape of the special-shaped cable-stayed bridge with universal hinge than that of the conventional cablestayed bridge.Therefore,it has important theoretical significance and engineering application value to study the structural characteristics and aligment control technology of the single pylon cable-stayed bridge with universal hinge.Based on a special-shaped cable-stayed bridge with single pylon and universal hinge,this paper studies the structural characteristics and key technology of aligment control of the special-shaped cable-stayed bridge with single pylon and universal hinge.First of all,the finite element simulation model of the special-shaped cable-stayed bridge with universal hinge single tower is established by Midas civil,and the reasonable completed bridge state and reasonable construction state are analyzed.Secondly,the influence of initial tension of stay cable,structural dead weight and structural stiffness parameters on the finished bridge alignment is studied.Then,based on the rotation characteristics of the universal joint,the influence of the initial tension of each pair of back ground anchor cable on the aligment deviation of the bridge tower in each construction stage is analyzed,and the control threshold of the aligment deviation of the bridge tower in each construction stage is proposed.Finally,the paper analyzes the influence of asymmetric tensioning of single steel strand of back ground anchor cable on the alignment of bridge tower,optimizes the tensioning scheme of the first level back ground anchor cable after the vertical rotation of bridge tower,analyzes the conversion process and method of bridge tower from temporary support to permanent support system,and puts forward the key technology of structural alignment deviation adjustment in the construction process.The results show that: in the construction process,the displacement of the bridge tower and the main beam changes greatly and the spatial effect is obvious,and the construction control should be guided by the principle of structural aligment control as the main and cable force as the auxiliary;When the initial tension of all cables changes by 5%,the top of the tower will have a displacement of25 cm along the bridge direction;Based on the allowable cable tension deviation in the code,the control threshold of tower alignment deviation is proposed to guide the construction;This paper puts forward the construction scheme that the first pair of cables are tensioned in three stages and the vertical rotating temporary steel wire rope can be released at the end of the second and third stage tensioning,and realizes the aligment control by setting the pre deviation of the structure and adjusting the cable force in stages.It is applied to the actual project to verify the reliability of the conversion scheme and aligment control measures of the main tower temporary support system proposed in this paper.This thesis mainly studies the key technology of alignment control in the construction process of single pylon cable-stayed bridge with universal hinge,which provides theoretical basis and technical data for the design and construction of similar bridges,and promotes the popularization and application of similar bridges and the diverse development of bridge forms.