Study On Structural System And Static Performance Of Precast Prestressed Concrete T-beam Bridge

At present,due to the needs of energy conservation,environmental protection and green development,bridge prefabrication and assembly technology is being widely promoted in China.T-beam is a common bridge type in bridge construction.It has important theoretical value and practical value to study the corresponding prefabrication and assembly technology.Precast segmental T-beam can be produced on a large scale,industrialized,streamlined and standardized basis.At the same time,transportation,matching,installation and construction become more convenient,which is more suitable for the rapid construction of urban bridges.Among them,the joints between T-beam segments are the most critical part of precast segmental Tbridge.The probability of local shear failure of joints is relatively high in practical engineering,and there is still a lack of systematic research on the structural characteristics and mechanical properties of this part.Therefore,this paper verifies the relevant test results,makes a comprehensive numerical analysis and theoretical research on the shear performance of the joints between T-beam segments,and further carries out the numerical simulation research on the mechanical performance of the whole bridge.(1)This paper introduces the application and research status of precast segment assembly technology,compares and analyzes the application scope,advantages and disadvantages of joint type and key tooth structure used in precast segment assembly,and puts forward a new type of T-beam joint structure,namely steel tenon shear key joint,aiming at the joints of key parts of precast segment beam bridge.(2)This paper optimizes the section structure of segmental T-beam,puts forward the structure form of mutation section which conforms to the design concept of precast segmental T-beam,completes the section division of T-beam according to the relevant requirements of practical engineering,and designs the structural drawing suitable for 40 m precast segmental T-beam.(3)The finite element model of the straight shear test of the dry joint is established and compared with the relevant test results.It is proved that when the model considers the accuracy of the material nonlinearity and contact to the bearing capacity and crack simulation,the finite element analysis results of the model can help to improve the shear capacity of the dry joint.The straight shear performance,failure form and crack development of the steel tenon joint are obtained law.(4)According to the nonlinear analysis results of the steel tenon shear key model,the structural drawing of the segmental T-beam is further improved.Based on this,the finite element model of the prestressed segmental T-beam is established.The load combination under various working conditions is applied to the steel tenon joint segmental T-beam,and the most unfavorable load combination for the 40 m precast segmental T-beam is considered.The stress characteristics of the segmental T-beam under the load are obtained.