Research On Reasonable Completed State And Construction Control Of Cable-Stayed Bridge

The cable-stayed bridge consists of main girder,main tower and cable.The structural system is economical and reasonable with strong leaping ability.The structural modeling is rich in variety and expression for bridge aesthetics.Therefore,in recent years the cable-stayed bridge has developed rapidly and became one of the most competitive bridge types.Cable-stayed bridges are statically indeterminate structures which have many internal forces and deformation states,so there is a problem of reasonable completion state.But there is no unified theory for cable force optimization so far.Scholars have different understanding.The construction process of cable-stayed bridge is very complicated while the structure system,load and boundary conditions are constantly changing.The ultimate goal is to ensure that the internal force and deformation of completed bridges meet the design requirements and expected state.It is also widely studied in construction technology at home and abroad.In this dissertation,an engineering example is used to analyze the reasonable completion state of cable-stayed bridges with different optimization methods.Through calculation and analysis,it is concluded that the zero displacement method is not suitable for long-span cable-stayed bridges.The minimum bending strain energy method takes the bending moment of the main girder as the objective function,the cable force distribution obtained is more uniform and the completed state determined is more reasonable.But the deflection of the main girder is large and the deformation of the whole bridge is more obvious.The cable force adjustment consistent with multi-objective function can deliberate the performance of multiple bridges and get a more reasonable bridge completion state.But this method is very subjective.In this dissertation,the construction control cable force of cable-stayed bridge is calculated by taking-away method.The calculation results show that cable tension force will increase as the progress of construction When cable spacing is very small,the interaction between cables is obvious.With the tension of the cable,the axial force and strain of the main tower increase,which will reduce the length of the cable and unload.In the first chapter,the research background and significance are introduced,and the development status and prospects of cable-stayed bridges are explained.In the second chapter,based on a example of cable-stayed bridge,the cable forces calculated by different optimization methods.And the final reasonable completion state is determined by the cable force adjustment consistent with multi-objective function.Chapter 3 calculates the construction control cable forces of cable-stayed bridges by taking-away method,and analyzes the variation law and influencing factors of cable forces.