Study On The Interfacial Bond Behavior Of Epoxy Mortar Layer Used In Hybrid Bonding Shear Connection

At present,stud shear connectors are usually used for steel-concrete composite bridges to assemble steel girder and concrete slabs to work together.When the stud connectors are loaded,there is stress concentration at the root of stud.Under the fatigue load of vehicle,the concrete slab may be locally damaged and cracked,and the stud connectors are fatigue fractured,which will reduces the durability of the composite structure.Another form of shear connection between concrete deck and steel girder is hybrid bonding that uses stud connectors and epoxy mortar shear layer at the interface.In this paper,studies on the bond interfacial behavior of epoxy mortar layer used in hybrid bonding shear connection are carried out,which lays a foundation for the further study of hybrid bonding shear connection behavior.The main work and conclusions are shown as follow:(1)Design and manufacture 15 epoxy mortar bonded push out specimens.The interfacial behavior of epoxy mortar layer is investigated.The results show that the failure of specimens are mainly due to the interface debonding between concrete slab and epoxy mortar layer.The epoxy mortar bonding have good shear capacity,obvious brittle failure,and relatively uniform interface bond stress.(2)Design and manufacture 15 epoxy mortar bonded push out specimens.studies are carried out on the interfacial behavior of epoxy mortar shear layer influenced by the thickness of epoxy mortar layer,normal stresses.Results show that the failure of specimens influenced by thickness only due to the interface debonding between steel beam and the epoxy mortar layer.The failure of specimens influenced by normal stress mainly due to the interface debonding between concrete slab and epoxy mortar layer.Changing the epoxy mortar layer thickness have little effect on the shearing capacity,increasing the normal stress can improve the bearing capacity and ductility.(3)7 epoxy mortar bonded push out specimens are designed and manufactured to study the interfacial behavior of epoxy mortar layer bonding with concrete slab and steel beam respectively,and investigate the mechanical behavior of hybrid bonding shear connection.Results show that epoxy mortar have a better interfacial behavior with concrete slab than steel girder.The epoxy mortar layer used in hybrid bonding shear connection can effectively provide shear resistance and reduce the stress of stud.