| Prefabricated beam slab bridge(hollow slab,T-beam,small box girder)has been widely used in bridge construction at home and abroad for its convenient and rapid construction,economic and practical,and environmental protection,especially in small and medium span bridges,accounting for more than 80%.The prefabricated components of this kind of bridge need to be connected by cast-in-place joints to form a whole after erection.However,the weak point of this kind of bridge is usually its joint position,and the probability of disease is very high.Ultra high performance concrete(UHPC)has excellent performance in compressive strength,tensile strength,flexural strength,fatigue strength,abrasion resistance and other mechanical properties and durability.It has been used in a number of prefabricated bridge joints at home and abroad,and is considered to have broad application prospects.But at present,the research on UHPC wet joint of prefabricated bridge designed according to the standard atlas of our country is less,and the relevant experience is also insufficient,which limits its promotion and application.In this paper,four point bending tests are carried out on the mechanical performance of the wet joint model of the bridge deck based on UHPC.The failure mode and bearing capacity of the specimens under different research parameters(steel fiber content in UHPC,overlapping method of reinforcement,reinforcement shape and interface treatment)are discussed.The finite element model is established by ABAQUS.Through experimental research and theoretical simulation,the following key conclusions are obtained.(1)The maximum bearing capacity of the bridge deck with cast-in-place UHPC wet joint is higher than that of the whole cast-in-place UHPC wet joint.(2)The tensile property and crack resistance of UHPC are improved obviously after using cast-in-place UHPC at the wet joint.The wet joint will not be damaged,but shear failure may occur outside the wet joint.(3)The bearing capacity and ductility of the specimens increase with the increase of steel fiber content in UHPC of wet joint section,while the ductility and bearing capacity of the specimens without steel fiber are lower.(4)The results show that the ductility of the specimens can be greatly enhanced by welding the steel bars in the wet joint area,but the change of the maximum bearing capacity is not obvious.(5)When the U-shaped reinforcement is used in the wet joint area,the ductility of the specimen is better than that of the straight reinforcement,but the maximum bearing capacity is not significantly improved.(6)Whether the interface is chiseled or not has little effect on the bearing capacity,failure mode and ductility of the specimens.(7)Through the use of ABAQUS finite element analysis software,the load deflection curve obtained is compared with the load deflection curve obtained from the test.It is found that the curve is in good agreement.Therefore,the reliability of the finite element modeling analysis is verified. |
