The FEA And Research Of Design Method On Thin-wall Core Box Cast-in-site Reinforced Concrete Hollow Floor System

Thin-wall core box cast-in-site reinforced concrete hollow floor is a new type floor system in which boxes(such as cabinet, octagon, quasi -ellipse etc.) are laid as the certain rule. Its reaction to the external forces is more reasonable, thus its concrete reinforcement is less. It may be placed once to form on spot, so its construction is convenient and its construction time is short. It adapts to the large column span and bay width floor or roof structures especially.Thin-wall core box cast-in-site reinforced concrete hollow floor is analyzed theoretically in this paper, combined with theoretical and technical study of such floor, which is one of the plan project of construction science and technology in hunan province. The main contents of this paper is divided into the below parts.1. The floor systems used widely in the factual engineering are summarized comprehensively so as to discover the advantages of the thin-wall core box cast-in-site reinforced concrete hollow floor system.2.The constructional specification of such floor is studied in order to point out the construction feasibility and present the advanced construction methods and the two orientational means abiding by the current building codes.3. A rational finite element model is established and such floor is made a non-linear analysis in the ANSYS which is an international common software. This thesis analyses the mechanical properties of 9m 9m single span thin-wall core box cast-in-site reinforced concrete hollow floor under simple supported and four-corner column supported boundary conditions, and a compare with waffle slab of equal concrete volume is made, supplying a certain theory gist for the such floor system. Thin-wall core box cast-in-site reinforced concrete hollow floor designed by analogouswaffle floor is suggested.4. The elementary analysis about the geometrical parameter influences of plate thickness and breadth of rib beam on mechanical properties of the thin-wall core box cast-in-site reinforced concrete hollow floor is also made. A single geometrical parameter influence on mechanical properties of such floor system is set forth.5. The ultimate bearing capacity of such floor is worked out by applying yield line theory to an equivalent uniform plate of the same overall dimensions and having the same moment of resistance per unit width as such floor. Further, reinforcing steel's setting up is optimized and some instructive conclusions are drawn.6. The equivalent waffle rib method is presented, which is a factual design procedure. The experimental mode of the plate-column structure supported by the four points is designed.