What Is Waffle Slab? | Types | Advantages And Disadvantages

WHAT IS WAFFLE SLAB?

A waffle slab is a platform with a reinforced concrete roof  or floor has a square grid with deep sides. This is also known as a grid slab. Waffle slabs at the entrances of hotels, shopping malls and restaurants are mainly used to install good lighting and artificial lighting.

Its main function is to withstand higher loads and longer distances than flat floors because these systems are lighter and therefore can be used for roofing and floor. They are also used where there is a restriction on the depth of the beams to obtain a clear height.

Classification Of Waffle Slab

Waffle slab are classified into the following types based on the shape of the slabs (PVC sheets):

1.   Triangular - pod structure

2.   Square - pod structure

 

Advantages of Waffle slabs

1.  Because these systems are lighter in weight, waffle slabs can carry heavier loads and longer distances than flat slabs.

2.  Suitable for intervals of 7 m - 16 m, Longer breaks are possible with post-tensioning..

3.  Waffle slab can be used as both ceiling and floor slab.

4.  These systems are lightweight, so significant savings on the structure are ensured as the light framework is required

Disadvantages of Waffle slabs:

Waffle slab is not used in typical construction projects.

The casting forms or moulds required for precast units are very costly and hence only economical when large scale production of similar units are desired.

Construction requires strict supervision and skilled labour.

Disadvantages of Waffle Slabs

Waffle slab was not used in conventional construction projects.

Its is expensive, so it is only economical when large scale production of similar units is desired.

Construction requires rigorous supervision and skilled labour.

 

DESIGN OF WAFFLE SLAB

§  The design of the waffle slap depends on the total area required for the waffle slab is the main point to design a waffle slab.

§  80 mm to 100 mm is usually thickness of waffle slab.

§  waffle slab overall depth is limited to 300 mm to 600 mm.

§  100 mm to 200 mm is usually width of waffle slab.

§  The distance between two ribs in a row is 600 mm to 1500 mm.

§  Using rebars to reinforcement for extra strength.

§  the waffle slab has reinforcement in the form of a mesh or individual bars.

§  Reinforcement in the waffle slab is two-way.

§  Small beams are connected with main horizontal beams that form a grid-like shape.

ALSO READ: MINIMUM SIZE OF  CONCRETE SLAB, BEAM & COLUMN

DETAILS OF WAFFLE SLAB

§  A waffle slab construction is generally suitable for flat areas.

§  The amount of concrete used in the waffle slab is less compared to other types of slabs.

§  Waffle layers have good shrinkage resistance.

§  Waffle slab is a structural component that is hollow from the top and has a grid-like structure at the bottom.

§  Waffle slab can be used for floor construction and ceiling.

§  A flat slab cannot be built for a longer span and also cracks can occur.

§  Waffle slab is a special type of slab that is mainly built for a long time and is resistant to cracking and sagging.

 

WAFFLE SLAB CONSTRUCTION

§  The waffle slab construction is done in three ways.

a)   In situ construction,

b)  Precast Construction

c)   Prefabricated construction.

§  As per the design and the size required waffle slab is cast in site

§  In the construction of the precast waffle slab, the slab panels are casted elsewhere and joined to the reinforcement.

§  In prefabrication of waffle slab, reinforcement is provided on the slab panels during casting.

§  Compared to the other two slab types, the construction cost of the slab made of prefabricated is higher.

§  Waffle slab construction is generally preferred for gaps of more than 12 meters.

§  Waffle slab construction requires approximately 30% less concrete and 20% less reinforcement.

 

 

ALSO READ: Know How To Calculate Loads On Column, Beam, And Slab

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