Calculation Analysis Of Deflection And Research Of Deflection Control For Cast-in-situ Concrete Hollow Slab

Cast-in-situ hollow concrete slab is one of the new floor systems; it has the advantage of large span, big space and lightness, etc, has been increasingly used in practical engineering in our country. However, the research of hollow concrete slab is still not perfect and having more to research. With the hollow plate to further increase the span, the problems which including applicability need to be resolved as soon as possible.Firstly, the article gives the analysis of the two direction flexural rigidity of the hollow concrete flat slab, and to introduce the calculation formula of two direction rigidity which considers the effects of the transverse ribs to the stiffness. To define this kind of concrete slab belongs to orthotropic or isotropic attribution. According to the principle of rigidity equal, the article convert it to common concrete slab and based on elastic theory to analysis its internal forces. Secondly, according to RuiCi method, this article gives the calculation formula of hollow concrete slab elastic deflection and elastic-plastic deflection with deferent loads. Then, the article introduces prestress to solve the issue of deflection control. The prestress could be seen as line load which exert under the plate, and produces upward deflection to reduce the original deflection. The artilcle gives the calculate method to define the prestress too. The article adopts finite element analysis to research the hollow concrete slab deflection. To set up two models which including common hollow concrete slab and prestressed hollow concrete slab. Lastly, the article takes a model experiment of hollow slab; the experimental model is1:8in scale and has2.1mx3m span. And to analysis the experimental results, ANSYS results and formula results.