| The steel-concrete composite beam is the composite structure that connects the steel beam and the concrete slab by shear connectors（head studs,perfobond strips,etc.）.Because of its advantages of both concrete beams and steel beams,The steel-concrete composite beam is used in bridge engineering widely.Compared with ordinary concrete,the lightweight and high-strength characteristics of lightweight aggregate concrete facilitate its application in bridge engineering.When designing composite beams in our country,safety and comfort are more considered,and there is relatively little attention to durability,which makes the performance of some composite beams unable to meet the requirements of use when they have not reached the design life.In this paper,constant current accelerated corrosion test,shear connector push-out test and Abaqus finite element analysis were carried out,and the degradation law of shear resistance of PBL shear connector and composite shear connector（PBL+ head stud）under chloride ion corrosion was obtained.（1）Based on Eurocode 4,10 push-out specimens of PBL shear connector and composite shear connector were designed and manufactured.Through the constant current accelerated corrosion test,PBL and studs obtained different degrees of corrosion.The failure form,shear capacity,load-slip curve of the shear connector were obtained,and the conclusion was drawn:With the increase of the corrosion rate,the shear capacity of the PBL shear connector and the composite shear connector decreases,and the shear capacity of composite shear connector decreases even more.Under the same degree of corrosion,the shear capacity of the composite shear connector is higher than that of the PBL shear connector.（2）ABAQUS finite element analysis software was used to model and analyze the two types of shear connectors,the mechanical characteristics of PBL shear connectors and composite shear connectors were obtained.Through parameter analysis,it is found that the concrete strength has the greatest influence on the PBL shear connector and the composite shear connector,followed by the thickness of the hole plate,and the stud shank diameter has a relatively little influence on the shear bearing capacity of the composite shear connector.The hole diameter（30mm-50mm）and the perforating rebar’s diameter（12mm-20mm）have no significant influence on the shearing capacity of shear connectors.（3）Through the collected corrosion stud test data and the test results of this article,the correlation law between corrosion rate and shear capacity of the studs,PBL shear connector was summarized,and then through multiple linear regression analysis and fitting,the calculation formula for calculating the shear capacity of the PBL shear connector and the composite shear connector under chloride ion corrosion was obtained. |
