Reinforced concrete slab-rib ceilings

Slab-ribbed ceiling: a) One-way working slab ceiling, freely supported, b) jw. restrained on supports, c) multi-span slab-rib ceiling, d) a ceiling made of multi-hole prefabricated slabs; 1, 2, 3, 4, 5, 6 - main reinforcement bars, 7 - distribution bars, 8 - outer wreath, 9 - inner wreath, 10 - multi-opening floor slab, 11 - wall block.

Reinforced concrete slab-rib ceilings. The slab and the rib are the load-bearing elements of the plate-rib ceiling. These ceilings are mainly used in these rooms, where a smooth ceiling surface is not required from the bottom and there, where the ceiling carries heavy loads, e.g.. in warehouses. The rib spans used are 4,5-7,5 m. The rib height is assumed 1/15 l (l - rib span).

The thickness of unidirectionally reinforced floor slabs is 1/30 plate span and not less than:
a) 5 cm in the case of roof panels,
b) 6 cm in the case of ceiling slabs,
c) 12 cm in the case of boards under the passages.

The ribs can be single-span or multi-span. Intermediate supports of multi-span ribs may be walls or binders based on poles, due to the continuity of the plates, Reinforcement bars are placed in the slab spans mostly at the bottom and at the top, over the ribs. If in the panel span, the upper fibers are stretched, then the reinforcement bars are placed in the tension zone, i.e.. at the top of the plate. Process openings of various sizes can be easily made in slab-rib ceilings, if such are needed for operational reasons. These ceilings are used more widely in frame construction.