Waffle slab isn'temployed in typical construction projects.
The casting forms or moulds required for precast modules are very expensive & hence only economical when large-scale production of indistinguishable units are desired.
Construction requires strict supervision and skilled workers.
Pitched roofs place a greater burden on the foundations of the building and demand a greater depth of the footings. Replacing a flat roof with a pitched roof on an existing structure is not always feasible.
Not feasible for buildings with multiple levels or complex plans.
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.
Provide architectural advantages. All the Electrical appliances can be installed easily in the gap of the ribs which can be architecturally aesthetic.
Superior Statics: Bubble deck slab has a superiority over the conventional slab as it has reduced weight, increased strength, fewer columns, and no beams or ribs under the ceiling.
Production and Carrying Out: The production is of higher quality through the automated production of prefabricated units. Minimum work at the site removes the possibility of errors and lightweight of the slab helps in easier erection with light and cheap lifting equipment.
Economic Savings: The major savings are found in materials (slabs, pillars, fundaments) up to 50 %. Due to its lightweight, transportation costs are heavily reduced.
Environmental Improvement: With the use of the bubble, 1 kg of plastic replaces more than 100 kg of concrete. Energy consumption for production, transport, and carrying out is very less. Thus, less emission of CO2.