Advantages of Plinth beam and proper height of plinth in residential buildings
Plinth beam belongs to a RCC member. The purpose of plinth beam is to detach the superstructure and the substructure and it functions similar to a tie beam to retain columns, walls etc.
Superstructure is located over ground level that comprises of columns, beams, slabs, masonry walls etc. Substructure is located underneath the ground level that comprises of foundation.
Advantages Of Plinth Beam In House Construction :-
1. To sustain the masonry load at ground floor level
2. The objective of plinth beams is to bear the dead weight of the masonry wall (brick/block wall over it) on ground floor level
Maintain Backfilled soil: Houses are normally built up 150-300 mm over the adjoining road level(s). Plinth functions as a retaining structure for the compacted soil that is applied to fill the empty space from foundation level to top of plinth
To check/circumvent differential settlement
Foundations are exposed to differential settlement when the soil underneath is not compacted perfectly. A differential settlement leads to cracks in the masonry walls. Plinth beam belongs to an integrated structural member and it facilitates minimizing the differential settlement in the structure.
To function as a Tie-beam: Load bearing strength of columns is based on slenderness ratio. Slenderness ratio is obtained from unsupported length of column to cross sectional area of column. If the length of column is increased, the slenderness ratio is also raised to reduce the load bearing strength of the building. In order to reduce the effective length of column, tie beams are arranged and in such a situation if foundation is very deep then RCC plinth beam should be arranged. For foundations below or equivalent to 6 feet, plinth also functions as a tie beam.
Suitable Height Of Plinth:
Plinth level should remain over the adjoining road level to stop the penetration of your house in the rainy season.
Sometimes, local municipalities re-carpet the existing roads devoid of extracting old road strata at the time of repairing or building up the roads. Under such situation, nearby properties may set out under ground level and it is not recommended for practical purposes and for vastu.
To stop penetration of water or storm water into the house from outside, plinth is built up in such a manner that the top of the plinth remains adequately over road level.
If the plinth is built up too high over the road level, then the adjoining parking area level will also be raised and problems will arise.
With proper height only 3-4 stairs are necessary to get to plinth level and the bikes can be easily driven, cars can be easily parked and throughout rainfall it will safeguard property from storm and drainage water.
Because of these problems, plinth height should retain very cautiously neither too high nor too low.
The perfect plinth height should be 1.5ft to 2ft high as compared to road level.