Research On Key Construction Technology Of Cable Stayed Bridge With Special Shaped Arch Tower

The special-shaped cable-stayed bridge is the product of people’s pursuit of innovative ideas in recent years.Its appearance is novel and the shape is beautiful.It occupies an important position in the urban landscape bridge.However,the special-shaped cable-stayed bridge has brought various unexpected problems to designers and engineers due to its unique structural shape and mechanical characteristics different from the conventional cable-stayed bridge.At the same time,people summarize and study this kind of cable-stayed bridge Therefore,this paper takes a special-shaped arch tower cable-stayed bridge——Wenchang bridge in Fangchenggang City as the engineering background,analyzes and studies the key technical problems encountered in the construction process of the special-shaped arch tower cable-stayed bridge,so as to provide technical support for the actual construction of the bridge,and provide reliable reference for the design and construction of similar bridge types in the future.The main contents and core achievements of this paper are as follows:(1)This paper studies the development trend of cable-stayed bridges with special-shaped pylons at home and abroad,analyzes the mechanical characteristics of Π-type girder commonly used in cable-stayed bridges,and summarizes the advantages and disadvantages of the current optimization methods of cable-stayed bridges for completion and construction;(2)According to the mechanical characteristics of Π-type girder,single beam method,grillage method and beam plate combination method are respectively used to simulate the internal force and deformation of Wenchang bridge under these three simulation methods.The results show that it is reasonable to use grillage method and beam plate combination method to simulate Π-type main beam,and beam plate combination method is more reasonable It is more accurate to use single beam to simulate the wide and thinΠ-type girder,which will lead to the distortion of calculation results;(3)In order to solve the problem of excessive camber in the construction of special-shaped arch tower,according to the structure of the special-shaped arch tower and the variation law of the stress and displacement of the tower column construction,three steel pipe trusses along the bridge direction and two external prestressed structures in the transverse direction are proposed as the temporary transverse bracing of the arch tower According to the observed structural stress and deformation data,it is found that the temporary transverse brace can effectively restrain the stress and deformation of the arch tower during construction.The maximum tensile stress at the root of the tower column is reduced from 22.40 MPa to 0.56 MPa,and the maximum horizontal deviation of the tower top is reduced from 287.53 mm to 14.50 mm,which meets the requirements of construction control accuracy and meets the actual engineering requirements;(4)Aiming at the unique cable structure of special-shaped arch tower cable-stayed bridge with both stay cables and horizontal cables,the simulation model of once completed bridge is established by using the finite element software of maidas/civil.Taking the control conditions such as main beam stress compression,reasonable structural deformation,small bending moment of Arch Tower and balanced cable force as the cable adjustment principle,the rigid support continuous beam method,zero displacement method and minimum bending energy method are used to analyze the dynamic behavior of Wenchang University The results show that the minimum bending energy method can basically meet the reasonable completion state,which is suitable for the optimization of cable-stayed bridge with special-shaped arch tower;(5)In order to obtain the reasonable and accurate initial cable tension force of cable-stayed bridge with special-shaped arch tower,the relevant model is established by using the forward installation iterative analysis method,and the innovation and improvement of the normal installation iterative analysis method are carried out.The iterative calculation results show that the improved forward installation iterative analysis method can accurately obtain the construction initial tension force,and the target cable force error of the completed bridge is controlled within 1% The calculation process is more simple and fast,which can effectively reduce the calculation workload and provide reference for engineering practice.