Experimental Study On Flexural Performance Of Composite Slabs With Groove Splicing Joint

With the development of construction industrialization,prefabricated buildings have been widely promoted and used due to their advantages of energy saving,environmental protection and convenient construction.As an important horizontal component of prefabricated buildings,reinforced concrete composite slabs with steel bar truss are commonly used in precast floor slabs as a result of their good overall working performance.In practical engineering applications,composite slabs usually need to set up splicing joints,and traditional splicing,monolithic splicing and split splicing are the main forms of lateral splicing joint of composite slabs.At present,although the commonly used form of monolithic splicing joint has good mechnical performance,the extended reinforcement on the side of the slab reduces the efficiency of factory production,transportation and lifting,as well as on-site construction of composite slab components,which to a certain extent limits the widespread promotion and application of composite slabs in prefabricated buildings.Therefore,it is of great practical significance to study a lateral splicing joint of composite slabs with reasonable force,reliable connection as well as convenient transportation and installation.Based on the above problems,a new form of groove splicing joint without extended reinforcement at the bottom of the composite slabs has been designed and developed.Through full-size flexural test,numerical simulation and theoretical analysis,the flexural performance of the cast-in-place slabs,composite slabs with post-cast strip and composite slabs with groove splicing joint were comparatively studied.The main work can be summarized as follows:(1)The basic design of the groove splicing joint is illustrated in detail,and its production process is clarified.The effects of different groove sizes and different types of connection reinforcement in the groove on the flexural performance of the composite slabs were studied by full-size tests,and the flexural performance of cast-in-place slabs,composite slabs with postcast strip and composite slabs with groove splicing joint were comparatively studied in terms of the cracking moment,flexural bearing capacity,crack development,deformation ductility and failure characteristics.(2)The finite element models of cast-in-place slabs,composite slabs with post-cast strip and composite slabs with groove splicing joint have been developed to analyze the flexural performance of each specimen during the loading process.The load-midspan deflection curves,crack development,strain of reinforcing bars and flexural failure process obtained from numerical simulation are compared with the test results.(3)Based on the verified finite element models,parametric analyses for the D-type groove splicing joint composite slabs with the groove length of 300 mm are carried out.The effects of the reinforcement ratios of the connection reinforcing bar,the thickness of the laminated layer and the depth of the groove on the flexural performance are studied.(4)Based on the current relevant design criteria for composite slabs,the cracking bending moment,ultimate bending moment,stiffness and deflection of cast-in-place slabs,composite slabs with post-cast strip and composite slabs with groove splicing joint are theoretically analyzed and compared with test results,which verifies the feasibility of designing and calculating the flexural performance of composite slabs with groove splicing joint according to the current design criteria.