Study On Bending Properties Of Precast Segmental Concrete Beam With Hybrid Tendons And Dry Joints Based On Numerical Simulation

The precast segmental concrete beam bridge with hybrid tendons and dry joints is a kind of beam which need to prefabricate beams in segments and then need to use tendons to construct the segments as a whole. Compared with traditional integral prestressed concrete in vivo, the type of bridge is economic and practical,which is currently applied in approach bridge and rail bridge in long-span bridges in China. With the increasing cost of social labor and the continuous improvement of steel corrosion technology in recent years, such bridge has been more widely used, and will become a trend in the future bridge construction and development. This paper relies on Guangdong provincial department of education features innovation project(2014KTSCX060)"Key issues research of precast segmental concret new beam bridge”. And through experimental analysis and finite element model analysis, the mechanical properties of precast segmental concrete beam with hybrid tendons and dry joints is studied. The main contents include the following aspects:(1)The application and research status of externally prestressed technology and segmental technology is introduced. The scope and the advantages and disadvantages of joint types and splines structure used in segmental are compared and analyzed. The mechanical properties of precast segmental and external prestressed concrete beam is analyzed in detail. Relevant norms and proposed formulas of bending capacity of segmental beams at home and abroad are summarized. And the advantages and disadvantages are pointed out.(2)Takingthe prestressing form of tendon, shear span ratio and the construction method of segmental as parameters, using large finite element software ANSYS to build a calculation model,the comparative analysis between test and theory of five precast segmental concrete beam bridge with mixed prestressing and dry joints is done. The changes of deflection and stress increment situation in prestressing tendon under the action of external loads is compared, relevant research results at home and abroad is combined. The mechanical properties and failure characteristics of the precast segmental concrete beam with hybrid tendons and dry joints 红e systematicly analyzed. Thus the impact of segmental beams stiffness, deflection changes, the case of joint open and the changes of prestressing tendon stress by the above-mentioned parameters is obtained.The reliability experimental results is verified.(3)Taking S4 beam as a reference beam, factors of bending properties of the precast segmental concrete beam with hybrid tendons and dry joints is studied, taking joints construction, web thickness, tendons, and concrete tendons strength as parameters,the influence on bending properties of concrete is studied.Possible factors in the precast segmental concrete beam with hybrid tendons and dry joints have been numerically analyzed. The conclusions can be used as technical guidance for the design and construction of segmental beams.