Study On Mechanical Properties Of Composite Slab And Connecting Members Of Assembled Cable Supported Steel-concrete Composite Floor Structure

As a new type of large-span prestressed composite floor structure,the assembled cable supported steel-concrete composite floor structure is mainly composed of connection between the plates and concrete composite floor slabs with steel bar trusses.In order to clarify the mechanical properties of composite slabs and their connecting members in composite floors.In this thesis,the composite slab composed of four steel bar truss composite slabs is selected as the research object,and the mechanical properties of the construction stage and the normal use stage are studied by the combination of test and finite element method.The influence of the parameters of the connection between the plates on the mechanical properties of the construction stage is analyzed,and the influencing factors of the mechanical properties of the composite floor in the normal use stage are explored.According to the test and finite element simulation combined with the existing specifications,the bearing capacity of the connectors between the slabs in the construction stage and the ultimate bearing capacity of the composite slabs in the normal use stage were analyzed and verified.The main research contents and conclusions of this thesis are as follows:(1)The pre-arch test of the composite slab in the construction stage was carried out to explore the mechanical properties of the composite slab under the upward concentrated load in the construction stage.The results show that the composite slab has good deformation and bearing capacity in the construction stage,and the connection between the slabs is still in the elastic stage.(2)On the basis of establishing the finite element model of the composite slab in the construction stage and verifying the correctness of the model,the parametric study of the connection between the slabs is carried out.The results show that for the composite slabs studied in this thesis,the height of the connecting web should be between 210 mm and 240 mm,the ratio of height to thickness should not be less than30,and the ratio of height to width should be between 1.0 and 1.2.(3)The static load test of the composite floor slab in the normal use stage is carried out,the test phenomena such as structural cracking and failure are observed and the corresponding load values are recorded.The results show that there is a good shear capacity between the new and old concrete composite surfaces.The ultimate bearing capacity of the composite slab is 23.9 k N/m~2,and the deflection value is 17.83 mm.The structure has good deformation and bearing capacity.(4)The finite element model of composite slab in normal use stage is established and the correctness of the model method is verified.Then,the parameters of concrete strength,rib beam height and composite slab thickness are analyzed.The results show that the main factors affecting the cracking load of concrete are concrete strength and rib beam height.The main factors affecting the ultimate bearing capacity of composite floor are the height of rib beam and the ratio of post-cast reinforcement.Factors such as rib beam height and rib beam reinforcement have a great influence on the deflection deformation of the composite slab,while the concrete strength and the thickness of the composite slab have little influence.The influence of the inter-plate connectors on the composite floor in the normal use stage is very small and can be ignored.(5)According to the structure of the connection between the plates,the bearing capacity is calculated in combination with the existing specifications.The ultimate bearing capacity of the composite floor unit can be calculated according to the specification.