Theoretical Analysis On Two-way Mechanical Properties Of One-way Cast-in-situ RC Hollow Slab With Circular Pipe And Research Of Construction Technology As Well

Cast-in-situ concrete hollow floor is a new kind of cast-in-situ concrete floor in which embedded fillers are regularly installed in advance in order to shape hollow space. As cavity-shaped material remaining in the floor forever, the embedded fillers mainly make the cavities more regular. It is not to be calculated their contributing to mechanical advantage, but it is obvious for them to better mechanical and applicable property, and to decrease the construction total cost. These advantages can be introduced as follow: dropping total weight of the building, increasing net height between adjacent stories, insulating sound and absorbing floor vibration energy, keeping up with the pace of sustainable development way of concrete. Among series of hollow slab with circular pipe, one in which there are inward RC ribs in only one direction, is called one-way cast-in-situ hollow slab, which even can contain such small-diameter piping as air-conditioner and vapour piping etc. in contrast to others with two-way ribs, resulting in clearer economy and applicability. A number of experiments and engineering practices proved that it has better two-way whole mechanical property. Meanwhile, explaining the mechanic remains discussing all along. In this paper, the author has comprehensively investigated, contrasted and analysed amount of experimental background, then advanced a new mechanic model that is elastic supporting continuous arch for mechanical means of hollow-slab in the direction perpendicular to hole axis. In detail, the compressed flange with a little of moment is equal to arch body and tensed longitudinal bars equals to tensile shaft connecting two foots of arch. The theory was proved to be true by means of non-linear definite element analysis. The arc-effect could well explain the mechanic, avoiding dispute about how to calculate inertia moment when explaining the mechanic using flexion-resistant rigidity. In addition, some problems of design, structure and construction of the hollow slab with inward winding-piping are introduced.