Study On Mechanical Properties Of Shear Connectors Of Steel-concrete Composite Beams Under Corrosion

Steel plate composite girder Bridges are widely used in bridge engineering with good stress form and rapid assembly construction.With the diversity of road transportation,the loading and transportation of hazardous chemicals tank is increasing,and traffic accidents are also frequent.The overturning of the transport vehicle carrying corrosive liquid leads to corrosive liquid leakage,which passes through the cracks in the bridge panel or the corrosion of the bolt connector on the steel-concrete joint surface,resulting in corrosion of the bolt connector.The corrosive substance will have chemical reaction with the bolt connector,which will reduce the diameter of the bolt connector and lead to the reduction of its cross-sectional area,thus affecting its shear performance,and eventually lead to the reduction of the bearing capacity and ductility of the steel plate composite girder bridge,affecting the safety of the steel plate composite girder bridge and the durability damage of different degrees.This paper focuses on the mechanical properties of steel plate beam stud connectors under corrosion and aims to master the evolution law of mechanical degradation properties of steel plate beam stud connectors under corrosion.The mechanical and shear properties of bolt under corrosion were studied systematically.The main research content is the following four aspects:（1）Tensile test of stud connectors subjected to corrosion.The tensile tests of 10 groups of stud connectors under corrosion were carried out to study the mechanical degradation law of stud connectors under corrosion,and the quantitative relationship models of nominal yield strength,nominal ultimate strength,elastic modulus,elongation and flexural strength ratio of stud connectors with corrosion time were established.A quantitative relationship model between the corrosion rate and corrosion time of stud connectors was established.The constitutive relationship model of bolt connector under corrosion was established.（2）Experimental study on shear performance of stud connectors subjected to corrosion.According to different corrosion time,six groups of specimens were designed to push out the stud connector under the action of corrosion,and the experimental study was carried out to study the shear property degradation law of specimens under the action of corrosion at different corrosion time.（3）Finite element numerical analysis on mechanical mechanism and influence parameter of shear performance of stud connectors under decay.The ABAQUS finite element analysis was carried out based on the push-out test of bolt connector under corrosion,and the parameters were further analyzed by the model.（4）Analysis of shear capacity and load-slip curve formula of stud connectors subjected to corrosion.Based on the analysis of 104 push-out test data at home and abroad,the accuracy and discreteness of the formulas for calculating the shear capacity of 6 kinds of stud connectors were counted,and the reliability of the formulas provided by the Chinese code was analyzed,and the corrosion coefficient factors of the shear capacity were fitted,and the formulas for calculating the shear capacity under the action of corrosion were proposed.Based on the results of push-out test,the load-slip curve formula was established,and the corrosion coefficient factor of load-slip curve was fitted,and the calculation formula of load-slip curve under corrosion was put forward.