The Research Of Design Method Of Cast-in-situ Concrete Hollow Slab

The cast-in-situ reinforced concrete hollow slab with ceiling formwork is a new kind of cast-in-situ slab, which is formed by using ceiling plate and rectangle box that are equally-arranged spaces in the solid slab. In this thesis, the internal force, bending calculation, limit bearable capacity analysis and suggestions on construction of cast-in-situ reinforced concrete hollow slab with ceiling formwork are explored. The main contents are as follows:1. The cast-in-situ reinforced concrete hollow slab with ceiling formwork refers to a slab with dense and small rib-reinforce. At the bottom of the plate there exist bidirectional dense ribs. According to the theoretical analysis and experimental research, the cast-in-situ reinforced concrete hollow slabs are slabs of ribs with flat plates bending-oriented, while the ribbed or waffle slabs are the cross girder system with slabs as its wingspan.2. Differential equations of the cast-in-situ reinforced concrete hollow slab with ceiling formwork are derived according to the orthotropic plate theory. The calculating formulae of the hollow slab's section bending moment and torsional stiffness is presented on the basis of its tectonic features. The analytical solutions of bending moment and deflection for the cast-in-situ hollow slab simply supported by four edges are also presented.3. The study of the damage of the the cast-in-situ concrete hollow slab puts forward the corresponding damaging forms based on the experiment, and thus the calculating formulae of limited bearable capacity are deduced by the principle of plastic hinged line theory. Calculating statistics show that hollow slab has adequate bearable capacity. Considering the effect of film domino offect, the formulae of bearable capacity has been revised.4. On the basis of theoretical analysis and experimental study, the design methods and constructive measures of cast-in-situ reinforced concrete hollow slab with ceiling formwork are proposed. By means of examples, the comparisons between the result of theoretical analysis and the result of non-linear model of software ANSYS are basically equal which desmonstrates the design method put forward in this thesis is feasible.