What Is a Plinth Beam | Its Necessity And Applications | Description About DPC

      "Plinth" meanings to a lower square base that supports columns, walls, and structures. Plinth beams are reinforced concrete beams that are constructed between walls and foundations. The mechanism of load distribution in any structure is: the load in the structure gets transferred from slabs into a column and from column into the foundation, in the foundation those loads get distributed among the soil.

Why is a plinth beam needed?

1.    For the loads on the walls, all the loads applied on the walls are distributed over the foundation evenly through the plinth beam.

2.    They can join all columns. As, columns are projected upward from the RCC Foundation, and plinth beam joins all the columns right from the foundation.

3.    When the foundation of the structures suffers settlement due to various causes like natural disasters or due to low grade of soil, the plinth beam prevents the expansion or propagation of cracks in the walls above from the foundation.

4.    Plinth beams are the structural element that supports our walls and acts as an element where the walls can rest i.e. it separates the walls from directly laying on the ground.

If we build walls on the soil or on the ground surface, where there is no plinth beam, then it not certain that the ground will hold up the wall. If there is black cotton soil around, then the wall will form various cracks due to the swelling of the black cotton soil under humid conditions. So, a plinth beam is necessary for our structure to be secured.

5.    The plinth beam prevents the entering of moisture into the building from the foundation. For this, DPC is done above the plinth beam.

6.    The plinth beam prevents the building from collapsing during an earthquake, as it splits the superstructure and substructure of the building.

Applications of a plinth beam

1.    Plinth beams must be constructed in high earthquake risk areas.

2.    The most important application of a plinth beam is to withstand outside actions such as water, tree roots, termites, etc. which could affect the life of the plinth.

 

Concrete grade suitable for plinth beam construction

While constructing a plinth beam, the strength of concrete should not be smaller than 20Mpa.

If we are mixing the concrete manually, then an extra of 20% cement needs to be added to the mixture for compensation for the losses.

 

Minimum dimension of a plinth beam

The thickness or depth of the plinth beam should not be smaller than 20 cm, whereas its width should match the width of the final course of the foundation.

 

Important Question:

Q. What do you mean by DPC?

Ans: DPC stands for Damp-proof course. DPC is a horizontal barrier in the wall designed to resist moisture rising through a structure by capillary action.

Usually, bricks also perform capillary action, which causes dampness on the walls, which ultimately causes the plaster of our wall to coat out.

DPC layers can be applied horizontally as well as vertically.

DPC layer is generally laid above the upper surface of the plinth beam or in between the brick masonry built above the plinth beam, which is on the ground floor.

Insulating, plastic, and flexible materials like butyl rubber, hot bitumen, plastic sheets, sheets of lead, copper, cement mortar, etc. are the widely used materials for damp-proofing.