What is waffle slab Slideshare?
CONSTRUCTION • Waffles are generally limited to the interior of a slab, leaving one or two of the forms out to create a solid fill around the supports. The solid fills provide the strength required for shear transfer to the supports.
What is a waffle slab system?
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.
Are waffle slabs any good?
If you are looking to create a strong structure that can go for decades without showing any signs of damage, waffle pod slabs are the way to go. This system features greater stiffness and strength compared to conventional footing methods. It offers greater resistance to cracking.
What is the maximum span for waffle slab?
The width of beams or ribs provided in waffle slab are generally 110 to 200 mm. Spacing of ribs recommended is 600 to 1500 mm. Reinforced waffle slabs can be constructed for the span up to 16 meters while beyond that length prefabricated waffle slab is preferable.
How do you make waffle slabs?
Example on Structural Design of Waffle Slab
- Solution. From basic span/effective depth ratio of 26, the trial depth of slab to be adopted = 7500/26 = 288 mm.
- Load Analysis.
- Analysis of the slab.
- Check for deflection.
- Design of Supports;
- Minimum shear reinforcement;
What are the advantages and disadvantages of waffle slab?
What Is Waffle Slab? | Types | Advantages And Disadvantages
- Because these systems are lighter in weight, waffle slabs can carry heavier loads and longer distances than flat slabs.
- Suitable for intervals of 7 m – 16 m, Longer breaks are possible with post-tensioning..
Is waffle slab precast?
Construction procedure of waffle slab Precast : In this case slab panels are casted somewhere and they are joined together with enforcement and concrete is filled. Prefabricated : In this case internal reinforcement is not needed as the slabs are already casted with some tension.
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.
Are waffle slabs cheaper?
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.
How do you calculate waffle slab?
Concrete Calculations
- Divide total m^2 of slab by 8.35 on 260 mm high slab.
- Divide total m^2 of slab by 7.80 on 310 mm high slab.
- Divide total m^2 of slab by 6.93 on 385 mm high slab.
- Divide total m^2 of slab by 6.30 on 460 mm high slab.
- Divide total m^2 of slab by 5.00 on 610 mm high slab.
How thick is a waffle slab?
This slab is usually 100mm thick with thickened edges varying between 300mm and up to 700mm deep. Throughout the slab there are also stiffening beams which are 300mm wide and vary in depth up to 700mm. These beams are spaced at a maximum of 6000mm to a minimum of 4000mm.
What are four different types of slabs?
One-Way Slabs on Beams.
Why is slab used?
A slab is a structural element, made of concrete, that is used to create flat horizontal surfaces such as floors, roof decks, and ceilings. A slab is generally several inches thick and supported by beams, columns, walls, or the ground.
What is the positive aspects of using waffle units?
Uses And Applications :
- Larger span of slab and floor with less number of columns.
- load carrying capacity is greater than the other types of slab.
- Savings on weight and materials.
- Good vibration control capacity.
- Attractive soffit appearance when exposed.
- Lightweight.
- Vertical penetrations between ribs are easy.
What are the advantages of a waffle slab?
Advantages:
- Larger span of slab and floor with less number of columns.
- load carrying capacity is greater than the other types of slab.
- Savings on weight and materials.
- Good vibration control capacity.
- Attractive soffit appearance when exposed.
- Lightweight.
- Vertical penetrations between ribs are easy.
Is code for waffle slab?
Method as proposed in IS code IS 456:2000 – “Plain and Reinforced concrete code of practice”, recommends designing ribbed slabs as an equivalent solid slabs where moments in the slab may be obtained from coefficients given in Table 26 of the code.
How do I calculate the number of Waffle pods?
Waffle Pod Accessory Calculations To commence, divide the total area m^2 by 1.51 to get the number of Waffle Pods required for the concrete slab.