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Rectangular hollow steel sections are widely used as a raw material in the construction industry. They are commonly used to make columns and shafts during construction of buildings and bridges. Determining the weight of a rectangular hollow section of steel helps to save the amount of steel used for a purpose and in turn the cost of the project.
Calculating the weight of rectangular hollow section of steel
To determine the weight of a rectangular hollow section of steel you would need to measure the length, breadth, height/depth, and density of the section. Once you have all these measurements you can simply apply the formula to calculate weight of rectangular hollow section.
Let us see how to calculate the weight of a rectangular hollow section of steel with an example:
L (length) = 1000 mm (1m)
h (height) = 200 mm
b (Breadth) = 180 mm
d (Density) = 8000 kg/m^{3}^{ }
The formula to calculate the weight of a hollow rectangular section is
Weight (W) = Volume (V) x Density (d)
To calculate the volume of the steel section we must first find out the area of the steel section. For this you would need to calculate the area of the outer rectangle and the inner rectangle separately and then subtract them to get the total area of the rectangular hollow section.
The dimensions of the outer rectangle are as given above which is:
h = 200 mm
b = 180 mm
Therefore, area (A) = h x b
= 200 x 180
= 36000 mm^{2}
Here are the dimensions of the inner rectangle:
h = 190 mm
b = 170 mm
A = h x b
= 190 x 170
= 32300 mm^{2}
Total area (A) = Area of outer rectangle – Area of inner rectangle
= 36000 – 32300
= 3700 mm^{2}
Converting 3700 mm^{2} to m^{2 }= 0.0037 m^{2}
Now we must find the volume of the section:
Volume = A x l (length)
= 0.0037 m^{2 }x 1 m
= 0.0037 m^{3}
Therefore, weight of the pipe, W = Volume (V) x Density (D)
= 0.0037 m^{3 }x 8000 kg/m^{3}
= 30 kg
Calculating the weight of the steel section is important for the overall calculations of your engineering or construction project. Accurate calculations can avoid wastage of your steel raw material and lead to cost savings.
Also read: Steel angle basics – Sizes, types, applications and rates
Standard sizes of rectangular hollow sections of steel
As per IS 4923, specifications for hollow steel sections for structural use, there are standard sizes that steel sections must follow while being sold in the market. Given below are a few standard sizes according to IS 4923:
Standard specification (lxbxt*) |
Weight (kg/m) | Area (cm^{2}) |
50.0 x 25.0 x 2.9 | 2.98 | 3.80 |
60.0 x 40.0 x 2.9 | 4.12 | 5.25 |
66.0 x 33.0 x 4.5 | 5.95 | 7.58 |
70.0 x 30.0 x 3.2 | 4.50 | 5.73 |
96.0 x 48.0 x 3.2 | 6.71 | 8.54 |
100.0 x 50.0 x 3.2 | 7.01 | 8.93 |
145.0 x 82.0 x 4.8 | 15.92 | 20.28 |
*t – thickness
For a full list of standard specifications click here
Rectangular steel sections can easily be attached to other flat surfaces as it offers a level surface that is easy to cut and requires only minimal edge preparation. This makes for cost-effective joints and welds.^{ }
Also read: What are the different types of steel channel?
Steel round bar: Types, advantages and uses