Study On Shear Performance Of Joints In Precast UHPC Segmental Bridge

Segmental prefabrication technology has the characteristics of short project cycle,small environmental impact,excellent alignment quality after completion of the bridge,and easy to be manufactured on a large scale.After decades of engineering practice,it has been widely used in domestic and foreign engineering examples.At the same time,the use of ultra-high performance concrete(UHPC)materials,while retaining its original advantages,further enhances the durability and portability of the segmental prefabricated UHPC bridges.As a form of assembly building vigorously promoted by the state,the future segmental UHPC bridges has good prospects for development.As the weak link of segment prefabricated UHPC bridges,the experiment and theory of UHPC joint are not perfect.Based on the experimental study of shear performance of UHPC joint,the finite element simulation is carried out,and the formula of shear capacity is optimized and adjusted.The main contents are as follows:(1)Aiming at UHPC joints structure,two groups of UHPC joint specimens are designed to carry out shear test in this paper to discuss the effects of tooth bond type,lateral stress level on shear resistance and failure mode of UHPC joints.Then,summarized the influence rules of each factor on shear resistance of UHPC joints.During the test,the cracking load,failure load,relative slip,crack development and failure mode of joints were observed.(2)Using the universal finite element analysis software ABAQUS to simulate the test UHPC joint specimens,and the results of finite element simulation are compared with the test results.The finite element model can simulate the test process well in the failure mode and the failure load.The tensile and compressive properties of UHPC materials are taken as parameters to analyse,and the results show that the tensile and compressive properties of UHPC materials are the best parameters.The strength has little effect on the failure load,but the compressive strength of UHPC has a significant effect on the failure load of UHPC joint specimens.(3)In this paper,the existing formulas of shear capacity of ordinary concrete joints are summarized,and the applicability and rationality of the formulas are analysed and compared.According to the test results of this paper and the shear test results of flat joints and single bond joints of common concrete and UHPC materials at home and abroad,then conducted the regression analysis,and obtained the shear bearing capacity formula suitable for UHPC joints.Precast UHPC segmental bridge conforms to the development requirements of prefabricated architecture.This paper has certain reference significance for the design of shear capacity of segment prefabricated UHPC bridge based on the test and theoretical research of the segment prefabricated UHPC joints.