Closure Control And Cable Tension Optimization Analysis Of Hybrid Girder Cable-stayed Bridge

The main girder of hybrid girder cable-stayed bridge is made of concrete and steel,which gives full play to the advantages of material properties.However,although the mechanical properties of the structure are improved,the design and construction control of hybrid girder cable-stayed bridge also become more difficult.Closure control of the main span and cable tension optimizationin are the key problems in the construction control and design of hybrid girder cable-stayed bridge.At present,there are few related literatures about closure control of hybrid girder cable-stayed bridge,especially about single tower hybrid girder cable-stayed bridge.Meanwhile,there are also defects in current cable tension optimization methods of cable-stayed bridges.Therefore,it is necessary to make a further study.In this paper,by using finite element software midas civil,closure control and tension optimization of completed status of bridge are analysed based on the engineering background of Yuekou hanjiang single pylon hybrid girder cable-stayed bridge.The main work is as follows:(1)By comparing the additional displacement and internal force of completed bridge caused by closure temperature differences,the effect on completed bridge state by temperature closure method is analyzed.Results show that if closure temperature difference can be controlled within positive and negative 4 centigrade,the additional displacement and internal force will be very small.This closure method is simple in construction technology and low in safety risk,so it is suitable for this bridge;(2)Alignment and tension construction control and stability in cantilever construction are analysed,which create favorable preconditions for the closure.Environmental factors that should be controlled strictly in the process of closure are determined by making closure sensitivity analysis.Effective final closure adjustment measures are worked out based on the analysis above.Finally,the closure scheme is made and the result of closure is evaluated;(3)The problems existing in the optimization analysis of cable tension of cable-stayed bridge by influence matrix method are analyzed.The results show that due to the nonlinear effect of cable-stayed bridge,when using influence matrix method to optimize cable tension,the influence of the matrix itself and the superposition principle will lead to obvious errors in the final result,which can not be ignored;(4)Based on the principle of reducing the change range of cable tension,an improved method is proposed.Validity of the improved method is verified.Finally,the improved influence matrix method is used to optimize the cable tension of this bridge and an ideal optimization result is obtained.