Calculating Loads Acting on Columns, Beams, Walls, and Slabs
It is essential that you have to be able to calculate the forces acting on different members of a structure quickly and efficiently, if you wish to be a civil engineer worth your salt. There are some very simple ways to do it. Today, we will talk about calculating loads acting on columns, beams, walls and slabs.
Calculating Loads Acting on a Column
About columns
A column is a vertical compression member in a structure. They are supposed to be at least three times taller than their breadth, and axial loads fall on them. That is, the weight of the superstructure goes through a column to the foundation safely. It is, therefore, a very important member of any RCC structure.
Column load calculation
We have the following data:
- Self-load of concrete: 2400 kg/m3 = 24.54 kN/m3
- Self-load of steel: 7850 kg/m3
- Column size: 300 x 600 mm cross section, 2.55 m height
Therefore,
- Self-weight of column
- = 1000 kg per floor
- = 10~12 kN or close
- Volume of Concrete
- = 0.30 x 0.60 x 2.55
- = 0.459 m3
- Weight of Concrete
- = 0.459 x 2400
- = 1101.60 kg
- Weight of Steel (1%) in Concrete
- = 0.459 x 1% x 7850
- = 36.03 kg
- Total weight of column
- = 1101.60 + 36.03
- = 1137.63 kg
- = 11.12 kN or close
Calculating Loads Acting on a Beam
About beams
Beams are horizontal members of a building which carry both the horizontal and vertical loads to the columns or girders. They also take care of the bending moment. Previously, we used to make beams out of stone or wood. But with the increasing weights and taller structures, we have to make RCC beams.
Beam load calculation
The calculation of beam loads is quite similar to column load calculation. We will use the same metrics here.
We have the following data:
- Self-load of concrete: 2400 kg/m3 = 24.54 kN/m3
- Self-load of steel: 7850 kg/ m3
- Beam size: 300 x 600 mm cross section (excluding slab thickness), calculating for every 1 meter of length
Therefore,
- Volume of Concrete
- = 0.30 x 0.60 x 1
- = 0.18 m3
- Weight of Concrete
- Weight of Steel (2%) in Concrete
- = 0.18 x 2% x 7850
- = 28.26 kg
- Total weight of beam
- = 432 + 28.26
- = 460.26 kg/m
- = 4.51 KN/m or close
Calculating Loads Acting on a Wall
About walls
Walls are those structural elements which provide shape, division and shelter to a space in a building. They can be either outer walls which are thicker and stronger, or inner walls that exist simply to divide the space.
Wall load calculation
Assuming we are using standard clay bricks for the wall.
We have the following data:
- Density of bricks: 1800~2000 kg/m3
- Wall thickness: 9 inches (standard outer wall in residential construction)
- Wall height: 2.55 meter (same as column)
- Wall length: calculating for each 1 meter
Therefore,
- Wall load per running meter
- = 0.230 x 1 x 2.55 x 2000
- = 1173 kg/meter,
- = 11.50 kN/meter or close
- If, however, we are using ACC blocks then the density of those bricks are 550~650 kg/m3
- In that case, using the same method as above, we get the load
- = 3.74 kN/meter or close.
Calculating Loads Acting on a Slab
About slabs
A slab is a flat monolithic plate-like structural element that provides a floor for something. They can be built as foundations to support the whole building, or they can be raised on top of columns and beams to make floors. Sometimes if the slab is light and small enough, it can be supported by just walls - though it is not recommended.
Slab load calculation
We have the following data:
- Slab thickness: 150 mm
- Slab size: 1x1 meter (calculating for each square meter)
- Floor Finishing load: 1 kN/meter
- Superimposed live load: 2 kN/meter
- Wind Load: ~2 kN/meter
Therefore,
- Slab Load Calculation
- = 0.150 x 1 x 2400
- = 360 kg
- = 3.53 kN or close
- Total slab load
