| Our country is in a critical period of great development of infrastructure,more and more bridges are being built or waiting to be built.Composite cable-stayed bridges can give full play to the advantages of concrete and steel materials,but the structural and mechanical characteristics of such bridges are different from those of other bridges.Based on the engineering background of a single pylon cable-stayed bridge with a span of 40m+45m+138m,and combined with the stress-free state method,this paper studies the construction control,mainly completes the following aspects:1.Introduces the development history and current status of cable-stayed bridges and hybrid girder cable-stayed bridges,the development and necessity of construction control,and briefly classifies the construction control methods of cable-stayed bridges.And summarizes the problems to be solved in this paper.2.The influence of cable assumed as a single material on the calculation of cable sag is studied by the improved multi-segment beam method.The results of the improved multi-segment beam method and the commonly used calculation methods are compared.3.The concept and shortcomings of the stress-free method are introduced,and some improvements are made to overcome the shortcomings of the stress-free method and verified in practical engineering.4.The stress-free method is used to determine the reasonable completed state of the bridge,and the application of the stress-free method in the cable-stayed-rigid frame composite system is discussed.Sensitivity analysis of important parameters in construction control of cable-stayed bridges(such as girder alignment,girder stress,tower top deviation displacement)is carried out.Based on the analysis of structural response sensitivity parameters obtained,the structural response that should be paid attention to during the construction control process of stress-free state method is summarized,so as to ensure the safety and stability of the structure in the construction process. |
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