Study On Mechanical Problems In Construction Of Simply-Supported Continuous Bridges

Simply-Supported Continuous Bridge, as a new bridge structure system which is developing rapidly in recent years, wins in many medium-span bridges scheme selection with unique advantages. It has the advantages of Simply-supported beams,such as mass production, high processing speed, easily constructing and so on, but also has the characteristics of continuous beams,such as good mechanical behavior, good integrity. The researches on Simply-Supported Continuous Bridge mainly focus on the construction area. The systematic researches on the mechanics in the construction of this type of brige are scarce.This thesis takes the project"Reseach on Control of Construction Craft and Lineshape of the linear control of Simply-Supported Continuous Bridge in××Highway Construction"as the background. Mechanical analysis is performed, according to engineering problems in the current project. According to practical engineering After doing search of a large number of domestic and foreign literature about Simply-supported continuous bridges and learning the structure system of Simply-supported continuous bridges, this thesis analyzed the characteristics of the bridges.the engineering is also analyzed by using finite element software MIDAS/civil and Dr.bridge program. The main research contents are as follows:1.When grasping the structure system of Simply-supported continuous bridges, analysis on stress characteristics prestressed T-beam of 5*30mT Simply-supported continuous bridges is carried out. For the phenomenon of insufficient camber of prestressed beams in the current construction, mechanical analysis is conducted and the impact of the insufficient camber is discussed. Stress of Pier of Simply-supported continuous bridges is calculated and the security assessment is given. Mechanical analysis of unequal span prestressed steel strands configuration is performed and mechanistic explanation is given. Working conditions of the transportation beam and plate on the girder is calculated and rationalized suggestions of transportation are given.2.The prestressing analysis of prefabricated components is conducted. The loss of prestress of steel strands is mainly researched and the percentage of the total loss and the individual in the overall percentage of prestress losses is obtained. The stress state of prestressed concrete girder is indicated and the impact of concrete on perstressed girder is obtained.3.The elastic modulus of concrete test is performed. The compressive strength test is compared with the value from specification and the relationship between concrete elastic modulus and concrete compressive strength. Site test of 30m T-beam is performed and the strain and deflection of prestressed beam in tension phase and the creep of prestressed concrete beam are tested. The test data and theoretical values are compared ,and the Test result have a good agreement with the theory.