Experimental Study On The Joint Structure And Two-way Mechanical Performance Of Prestressed Composite Slab Connected Without Gap

With the development of building industrialization,various new prefabricated building structures are built.As a new development trend of construction industry,building products with large span,bay and flexible layout of building space,such as "variable house type",put forward higher requirements for the span,stiffness,industrial production,assembly efficiency and quality of the existing assembled composite floor slab.In this paper,a prestressed two-way composite slab which is connected by a new type of joint is taken as the research object.The mechanical properties of the slab and the grid are studied by means of experiment,numerical analysis and theoretical analysis.The main contents of this paper are as follows:(1)The static loading tests of 4 pieces of composite slabs connected without gap and 1 piece of prestressed composite slab with a span of 6 meters are designed and completed.The bearing capacity,deflection,crack distribution and strain data of concrete and reinforcement are obtained.The influence of stirrup position,laminated layer thickness and jointsplicing form on the mechanical properties of the spliced plate are analyzed.Aand the bearing capacity of the prestressed composite plate are is also analyzed.Based on experimental results,the design method of composite slab connected without gap and prestressed composite slab are discussed,which provides support for the theoretical derivation of this kind of slab design method.(2)The static loading test of the two-way composite slab which is composed of two prestressed single composite slabs is completed.The relevant data of crack development trend,deflection deformation and load distribution change in each loading stage were obtained.According to the load distribution law of isotropic slab,the influence of spallation joint on its the mechanical performances is analyzed.Based on the test results and the theory of plastic hinge line,the bearing capacity of the lattice slab is analyzed,and the experimental results agree well with the calculated results.(3)Based on the theory of elastic mechanics and virtual work,combined with the test results of prestressed composite slab and composite slabs connected without gap,the elastic and plastic design methods of the composite floor are put forward,and the influence parameters of the bidirectional behavior are defined,which provide support for the parameter setting of the numerical simulation analysis.(4)By using ABAQUS finite element software,the test models of composite slabs connected without gap and the laminated floor are established,and the influence of each parameter on the mechanical performance is simulated.Combined with the test results,the influence of the number of joints and the thickness of the laminated layer on the stiffness of the joint slab is analyzed,and the stiffness calculation method of the two directions of the zone plate is proposed.Based on the simulation results,the elastic and plastic design methods and stress distribution of the lattice plate are verified,which provides reference and support for the design.