Which slab is better waffle pod slab or raft slab?
Which slab is better waffle pod slab or raft slab?
The main benefit of using waffle pod slabs is that they are drastically cheaper than traditional raft slabs. Waffle pod slabs use foam void formers to create the volume required for the ground slab. Conventional raft slabs, on the other hand, create the slab entirely from concrete and reinforced steel.
Why are waffle slabs used?
WHY WE PROVIDE IT Waffle slabs provide stiffer and lighter slabs than an equivalent flat slab. The speed of construction for such slab is faster compared to conventional slab. Relatively lightweight hence economical.
What is the meaning of waffle slab?
A waffle slab or two-way joist slab is a concrete slab made of reinforced concrete with concrete ribs running in two directions on its underside. The name waffle comes from the grid pattern created by the reinforcing ribs.
Where is ribbed slab used?
Ribbed slabs are suitable for medium to heavy loads, can span reasonable distances, are very stiff and particularly suitable where the soffit is exposed. Slab depths typically vary from 75 to 125 mm and rib widths from 125 to 200 mm. Rib spacing of 600 to 1500 mm can be used.
Is a waffle slab cheaper?
Waffle pod slabs are innovative because they use polystyrene void formers rated for efficient thermal insulation. These factors generally mean that a waffle pod slab will be significantly cheaper than a regular concrete raft slab.
Is waffle slab good?
They work perfectly well on non-reactive sites, slightly reactive clay sites and some moderately reactive clay sites. Waffle slabs are not recommended for use on highly reactive clay sites (Class H1 and H2) because the requirements for good drainage will be nearly impossible to achieve.
What are the disadvantages of waffle slab?
The disadvantages of waffle slab are as follows:
- Require greater floor-to-floor height.
- Requires special or proprietary formwork which is costly.
- requires strict supervision and skilled labor.
- Difficulty in maintenance.
- Not suitable in highly windy area.
Does waffle slab need Beam?
Characteristics of Waffle Slabs Waffle slabs are generally suitable for flat areas. Volume of concrete used is very less compared to others. The reinforcement in the waffle slab is provided in the form of mesh or individual bars. Separate excavation for beams is not required in case of waffle slab.
What is the disadvantage of ribbed slab?
Disadvantages of Ribbed and Waffle Slabs Not suitable where the live loads are huge as heavy manufacturing buildings, warehouses. The thickness of the slab is controlled as the requirement of fire resistance. Formwork cost is high. Sometimes difficult to install the electric equipment.
Why do we use ribbed slab?
Ribbed and waffle slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extent of foundations. They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals.
Do waffle slabs have footings?
Waffle slabs are a reinforced concrete footing and slab systems constructed on the ground. They consist of a perimeter footing (edge beam) and a series of narrow internal beams (strip footings) at one metre nominal centres running each way through the slab.
Is waffle pod slab cheaper?
Which is deeper a waffle slab or a ribbed slab?
Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction. Normally the ribs and the beams are the same depth. A thin topping slab completes the system. Waffle slabs tend to be deeper than the equivalent ribbed slab.
Which is better, a flat slab or a ribbed slab?
How big is a waffle pod slab in inches?
The name really describes the shape of the finished slab if you could look at it from underneath. The slab is set up on a grid of cardboard or polystyrene boxes that are 1200mm x 1200mm. They are set out in such a way that the slab has a grid of beams at 1200mm centres in both directions under the flat floor surface.
Which is better a waffle slab or casting?
In the prefabricated construction of waffle slab, the reinforcement is provided in the slab panels while casting. The construction cost of the prefabricated slab is higher as compared to the other two slabs. Construction of the waffle slab is generally preferred for spans longer than 12 m.
Which is the best description of a waffle slab?
The waffle slab or ribbed slab is a structural component that is plain at its top and has a grid-like system on its lower surface. The top of the ribbed slab is generally thin and the bottom grid lines are often ribs that can be placed perpendicular to one another.
How much concrete do you need for a waffle slab?
Waffle slab requires only 70% of concrete and 80 % of steel from the concrete and steel used for stiffened raft. The construction of waffle slabs can be done by three ways as follows.
What are the different types of ribbed slabs?
There are two types of ribbed slab system One way ribbed slab system Two-way ribbed slab System (Waffle system)
Why do you need a ribbed concrete slab?
They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction. Normally the ribs and the beams are the same depth. A thin topping slab completes the system.