Plinth Beam

1 Name of Work & Description

RCC (Reinforced Cement Concrete) Plinth Beam: Plinth Beam is a Structural which is located at Plinth level and shearing a load of structures an transfer it to footing. Plinth beam is necessary when foundation depth is more than 1m, as well as if foundation depth is more than 3m, need to design tie beam below plinth beam level. because Columns are vertical member and they are not capable to bear vertical load more than 6m, in a column if reinforced steel is not more than 4m, so need to design tie beam at 3m level and then plinth beam at plinth level.

Generally Size of Plinth beam is 300x600 but it is depend on Design of building or structure as well as it is depend on location of building and also depend on structural designer.

Types of Plinth Beam
1 Tie Beam
2 Plinth Beam

2 IS Code No.

Plain and Reinforced Cement Concrete IS Code: IS456:2000
Code of Practice for laying in-situ Cement Concrete Flooring: IS2571:1970
Methods of tests for aggregate for concrete: IS: 2386
Compressive strength test for cement mortar cubes: IS: 2250
Methods of sampling and analysis of concrete: IS: 1199
Specifications for fine & coarse aggregate from natural sources for concrete: IS: 383

3 The Drawing Needs to Read.

Following drawing need to study before start Plinth Beam Work.
1 Footing Sectional Drawing
2 Plinth Beam Sectional Drawing
3 Layout of Foundation
4 Plinth Beam layout and Schedule. 
5 Level Drawing.

4 Location of Work

Plinth beam is Located at below plinth level, that mean Plinth beam location is Below Finish Floor Level, and tie beam location is 1m below ground level.
5 Standard Procedure of Work (Step by Step)
Following procedures need to follow before start Plinth Beam Work.
1 Checking of Excavation Level and Foundation depth, depth of PCC, plinth Beam Level, etc.
2 Checking of PCC Level
3 Fix the Reinforcement as per schedule drawing.
4 Fixing of shuttering ply side as per the size given in drawing, 
5 Keep Top level of plinth beam is uniform.
6 Fill Concrete as per given design mix.
7 On next day remove shuttering and regular curing to be done.

6 Checkpoints

Plinth Beam Checkpoints is as follows
1 Excavation level
2 Plinth Top level
3 Depth of Foundation
4 Cutting of Steel
5 Reinforcement of Steel
6 Shuttering of Plinth Beam
7 Thickness and Size of Plinth beam
8 Grade of Concrete
9 Quality of Concrete
10 Curing

7 Equipments and Machinery

Cast in situ concrete required following Material
1 0.5 Bag/1 Bag Manual or semi automatic Concrete Mixure.
2 Weight batcher
3  Wheel Borrow
4 Shovel & Ghamela
5 Thapi,
6  Line dori
7 Measurement Tape
8 Auto level and staff.

8 Measurements and Quantity Survey

Pinth Beam Concrete is measuring in Cubic Meter and Shuttering is in Square Meter.
Following are the procedures to take and write the measurements of Plinth Beam.
If Size of Plinth Beam is 300mm X 600mm 
Now we need to find out lenght of plinth beam from structural drawing or architecture drawing, now a days we should we need to found autocad drawing soft copy of structural drawing, with the help of this drawing we should be measure length of beam.
Now we need to know about shuttering Quantity
Shuttering Quantity in Square Meter: 
Size of Plinth Beam: 300mm X 600mm
length of Plinth Beam: 3m
Shuttering Quantity : 3m x0.6m x 2 Sides = 3.60 Sqm
Area of Shuttering : 3600 Square Meters

Concrete Quantity in Cubic Meters:
Size of Plinth Beam: 300mm X 600mm
Length of Plinth Beam : 3m
Concrete Quantity : 3m x0.3mx0.6 =0.540 Cum
Concrete Quantity of Plinth Beam :0.540 Cubic Meters

9 Checklists

Checklist for Concrete is called Pour Card.
1 Excavation Level, Plinth Top Level is Checked.
2 Steel cutting as per schedule
3 Steel reinforcement is checked and found as per drawing.
4 Formwork is cleaned and oiled
5 Formwork free from holes and gaps.
6 Formwork size is as per drawing.
7 Formwork is in line level and plumb.

10 Quality Tests

Compression test of Cube
Testing of Cement
Testing of Aggregate

11 On-site Experiences

Focous of Dowel bar installation process: we are generally follow typical process of dowels bar installation process as lot of contractor follow wrong procedure installation of dowels. they are using Ld(Development Length)+10d+lap lentgh of bar in footing concrete after completion of footing concreting they are doing plinth beam work, while plinth beam reinforment work, the steel need to rebend and start the reinforcement but while rebending of steel there are lot of chances of minor cracks on steel at bend, or many times steel will cut. so we need to follow standard procedure as need to pass dowel bars from footing stuttering so we should keep straight bar in plinth beam.which will be easier than old typical procedure.
Mr. Gorakh

CBEC India