Study On Reasonable Prestress Of PC Wide-width Main Beam Of Hybrid Girder Cable-Stayed Bridge And Analysis Of Prestress Loss

With the rapid development of bridge construction in China,cable-stayed bridges are widely used due to their large spanning capacity,beautiful appearance and clear force.For the design of the upper structure of the concrete beam of the hybrid girder bridge,the prestress design is one of the important components.Whether the prestressing design is reasonable or not with the great significance to the safety and durability of structures.In this paper,the Jiayu Yangtze River Highway Bridge is used as the engineering background.The full-bridge analysis model is established by the finite element analysis software Midas.The static analysis of the main beam of the whole bridge is carried out,and the prestressed design and its corresponding topics are studied.as follows:(1)Reviewing the historical development process of cable-stayed bridges,briefly introducing the structural system and characteristics of cable-stayed bridges,expounding the research status of prestressed concrete development,introducing the basic theory and method of design calculation of cable-stayed bridges,and rationally forming bridges.The determination of the state,based on the principle of prestressing configuration,describes the classification of prestress loss and its theory.(2)According to the actual project,the Midas finite element analysis model is established,the static analysis of the main beam of the whole bridge is carried out,the principle of stress balance method is introduced to determine the feasible range of the dead beam moment of the main beam,and the concept of reasonable prestress is proposed.The analysis of the prestressing force of the beam is carried out.The results show that the prestress of the concrete main beam is larger than the reasonable prestress in the state of the bridge,and the prestress of the actual arrangement is within a reasonable range.The main beam of the concrete and the main beam of the steel are loaded.The moments are all within the feasible range,both the concrete main beam and the steel main beam are all under full compression,and the cable-stayed bridge meets the requirements of reasonable bridging state.(3)Corresponding to the prestress loss law of wide box girder used for long-span cable-stayed bridge,the actual prestress loss is known through field test to provide theoretical basis for construction control.The test results show that the actual pipe friction resistance parameter is larger than the standard value,but it has little effect on the bridge stress.By changing the pipe friction resistance parameter of the finite element model,the influence law of the friction parameter on the full bridge deflection,internal force and stress is obtained.The influence for the data of the k on the bridge is greater than the μ,which provides guiding significance for the design and construction of the same type of bridge in the future.(4)The actual measurement and analysis of the stress of the control section of the concrete main beam is carried out,and the correctness of the deviation coefficient of the prestressed pipeline is verified.The effective data reference is given for the construction process of the whole bridge and the determination of the bridge state.