Research On Construction Control Technology Of Tower And Girder Synchronized Concrete Cable-Stayed Bridge

As one of the most competitive bridge types in long-span bridges,cable-stayed bridges occupy an important position in the field of modern bridges.Compared with the traditional construction method,the tower-beam synchronous construction method realizes the synchronization of the construction process by simultaneously constructing the main beam and the bridge tower,thus significantly shortening the construction period.The main advantage of this method is that it saves the time of pouring the upper tower column,thus improving the construction efficiency and reducing the adverse effects on traffic and surrounding environment.Therefore,based on the background of Qingshuijiang Bridge,this paper makes an in-depth study on the synchronous construction control technology of concrete cable-stayed bridge.The main research contents and results of this paper are as follows.(1)The determination methods of reasonable completion state of cable-stayed bridge are summarized,and the advantages,disadvantages and characteristics of different methods are analyzed.Taking Qingshui River Bridge as the background,the rigid support continuous beam method,zero displacement method and minimum bending energy method are used to adjust the cable of the bridge,and the reasonable bridge state is determined.The results show that the cable tension obtained by the minimum bending energy method makes the bending moment distribution of the main beam more uniform,and the initial tension of the stay cable can improve the mechanical properties of the structure.(2)Aiming at the problem that the cable force of the completed bridge and the target cable force are not identical,the forward iteration method is used to iteratively calculate the process of constructing the tower first,then followed with the beam.The global synchronous construction of the tower and beam is also considered.At the same time,the mechanical behavior of the two construction methods is compared and analyzed,and the advantages and disadvantages of the two construction methods in the construction of cable-stayed bridge are clarified.It is found that when the global tower-beam synchronous construction is adopted,the bridge tower alignment is prone to curvature mutation.(3)For solving the issue of the sudden change of curvature of bridge tower alignment during synchronous construction of global tower and beam,the corresponding control methods are proposed: weight method,synchronous construction of local tower and beam,and pre-camber setting method of bridge tower.The results show that the synchronous construction of local tower beam has absolute advantages in structural stress and practical application.(4)The effect and influence law of the weight method and the cable adjustment method in controlling the tower deviation error,structural stress and alignment are compared and analyzed.On the basis of the background project,the influence matrix of the bridge state quantity is proposed when the tower deviation is controlled by the weight method.Aiming at the problem of bearing reaction force exceeding the limit in construction engineering,the partial unloading method of compressive load and the cable adjustment method in construction stage are proposed.Finally,the sensitivity analysis of the parameters affecting the tower deviation during the construction process is carried out.The results show that the weight of the main beam has the greatest influence on the tower deviation.