Abstract: Assembled cable supported steel-concrete composite floor is a new type of long-span prestressed composite structure. In order to explore the mechanical properties of the floor part of the composite floor, the standard floor element formed by the connection and combination of four slot laminated plates through inter plate connectors was selected from assembled cable supported steel-concrete composite floor. Taking this as the research object, the mechanical performance of it in the normal use stage was simulated and analyzed by finite element method.
The simulation results show that due to the existence of rib beam and post cast strip, in the initial stage of loading, the single slot composite plate element takes the lead in two-way bending deformation, and the mid span deflection is the largest. With the continuous increase of load, the overall bending deformation of composite floor unit occurs, and the deflection deformation at the middle of the span is the largest. When the loading is completed, the deflection value at the middle of the span is 59 mm. Under the action of external load, the concrete of composite slab element appears obvious plastic damage along the span direction, which indicates that the bending stiffness of simply supported composite slab element at both ends is related to the section perpendicular to the span direction. In order to explore in detail the effects of concrete strength, thickness of composite layer, height of rib beam and height of connectors between plates on the flexural stiffness and other mechanical properties of composite floor slab, thirteen finite element models were established to analyze the variable parameters of the laminated plate and the connection between plates of the grooved reinforced truss. By comparing the mid-span load-displacement curves under the same load and boundary conditions, the effects of different factors on the flexural performance of composite floors were explored.
The results show that when other conditions remain unchanged, with the increase of the height of the rib beam, the flexural stiffness increases sharply and the displacement decreases rapidly. The height of the rib beam increases from 400 mm to 700 mm, the flexural stiffness increases by 322.6% and the displacement decreases by 99%. As the thickness of composite layer increases, the bending stiffness increases and the midspan displacement decreases. When the thickness of composite layer increases from 40 mm to 70 mm, the bending stiffness increases by 24.2% and the displacement decreases by 54.7%. With the increase of concrete strength, the bending stiffness increases slightly but the midspan displacement has no obvious change. When the concrete strength increases from C25 to C40, the bending stiffness increases by 10.1% and the displacement fluctuates between 55 mm and 60 mm. Only changing the height of the inter-plate connector does not change its central position which has little effect on the bending stiffness and deflection. When the height of the inter-plate connector increases from 300 mm to 360 mm, the bending stiffness increases by 8.0% and the displacement decreases by less than 10%. In summary, the rib beam height has the greatest impact on the overall bending stiffness and mid-span displacement of the composite slab, followed by the thickness of the composite layer, and the concrete strength and the height of the connection between the slabs have little impact.