Ribbed slab system which consists of a series of parallel reinforced concrete T beams framing into reinforced concrete girders. The slab is the flange of the beam and the extended part is the web. The extended part is known as ribs. The spacing between the ribs should be in general 20-30 inch. The ribs are tapered in cross-section in its lower part.
Types of Ribbed Slabs
One-way Ribbed Slab System:
Two-way Ribbed Slab
Advantages of Ribbed and Waffle Slabs
- In this type of slab, the tension stress is eliminated in the tension side of the slab. The strength of concrete in tension is very small and so elimination of much of the tension concrete is done by the use of pan forms.
- Economical where the live loads are fairly small such as apartment houses, hotels.
- Long slab spans can be constructed through ribbed and waffle Slabs. In many cases, long spans are desirable in the building. Ribbed or waffle slabs are an easy solution for this purpose.
- Provide architectural advantages. All the Electrical appliances can be installed easily in the gap of the ribs which can be architecturally aesthetic.
- Slab thickness of ribbed or waffle slabs is less than other slab systems. Therefore the weight of slab is reduced. This saving of weight can change in structural characteristic.
- Lighter and stiffer slab than an equivalent flat slab.
- Reducing the extent of foundations by reducing the ultimate load.
- They provide a very good form where slab vibration is a viable issue.
These are the types and advantages of ribbed slabs.