Experimental Study On Performance Of Prestressed Concrete Frame Joints With Hidden Corbel

Prefabricated building is one of the important construction methods that adapt to the development of the times.It has the advantages of short construction period,fast construction speed,low environmental pollution,and resource conservation.Incorporating prestressing technology into the design of prefabricated buildings can effectively solve the problem of node connection of prefabricated buildings,so as to greatly improve the safety performance of prefabricated buildings.Based on this,the research on the mechanical properties of prestressed assembled nodes has important practical engineering significance and broad application prospects.Since the research of prestressed prefabricated joints in China is still in its infancy,it lacks perfect design methods and standard systems.Based on the existing research,this paper carried out experimental research,finite element simulation and theoretical analysis on the mechanical performance system of prestressed assembled nodes with hidden corbels.The main work completed and the research results obtained are as follows:(1)A quasi-static load test study was carried out on the prestressed prefabricated concrete frame joints with hidden corbels,and the failure form of the prestressed prefabricated concrete frame joints with hidden corbels under low-cycle reciprocating load was systematically analyzed,Ductility,energy dissipation capacity,residual deformation,node stiffness,node strength,etc.At the same time,the comparison test analysis with the integral cast-in-place concrete frame joints shows that the prestressed assembled concrete frame joints with hidden corbels have the characteristics of equal to or even surpass the strength and rigidity of the cast-in-place integral concrete frame joints,the prestressed prefabricated concrete frame joints with hidden corbels can produce large geometric deformation under the action of reciprocating load,and it has good self-reset ability.Its failure form is mainly reflected by the concrete baroclinic failure at the location of the hidden corbel.(2)ABAQUS software is used to establish a finite element model of the nodes in the prestressed concrete frame with hidden corbels.The correctness of the finite element model is verified by comparison with the test results.With the help of the finite element model of the nodes in the prestressed concrete frame with hidden corbels,the hysteretic energy dissipation performance of the nodes in the prestressed concrete frame with dampers was studied;A series of finite element analyses were carried out on the failure forms of the nodes in the prestressed concrete frame.The analysis results show that the energy dissipation capacity of the nodes in the prestressed concrete frame with dampers will be greatly improved;CFRP has a good reinforcement effect on the weak parts(hidden corbels)of the nodes.(3)Combined with the test results of prestressed concrete frame joints with hidden corbels,a theoretical model study was carried out on the prestressed concrete frame joints with hidden corbels.By defining the relevant limit states of the prestressed concrete frame joints with hidden corbels,the corresponding load and displacement under each limit state are obtained,and then the skeleton curve is obtained.At the same time,according to the derived load-displacement equation,the stiffness variation characteristics of the prestressed concrete frame joints with hidden corbels during the loading process are obtained.