How to Calculate Weight of Steel bar dia of 8mm, 10mm,12mm, 16, 20, 25, 28, 40 mm Used in RCC Structure

How to Calculate Weight of Steel bar Used in RCC Structure

There are two ways to calculate the weight of steel bar used in RCC work. You can calculate the weight either using the formula or following the general procedure. The formula will help you to get quick results. So, it will save your time. But the general way will help you to know the exact way of calculation.

Calculate the Weight of Steel bar by Using Formula

Weight of steel bar can be calculated by using (d2 ÷ 162) formula, where ‘d’ is the dia of a bar in mm.

Example 1: Let’s assume the dia of a bar is 12 mm.

So, the weight of bar will be = (122 ÷ 162) = 0.888 kg/m.

Example 2: Let’s assume the dia of a bar is 12 mm and length is 3 m.

So, the weight of bar will be = (122 ÷ 162) × 3 = 0.888 × 3 = 2.664 kg.

Example 3: Let’s assume the dia of a bar is 16 mm and length is 4.5 m.

Therefore, the weight of bar will be = (162 ÷ 162) × 4.5 = 1.58 × 4.5 = 7.11 kg.

Example 4: Let’s assume the dia of a bar is 20 mm and length is 10 ft.

Length of the bar is given in feet. So, we need to convert it in a meter. 10 ft = 3.048 m. [Note: 1ft = 0.3048 m]

The weight of the bar will be = (202 ÷ 162) × 3.048 = 2.469 × 3.048 = 7.52 kg

Calculate Weight of Bar by Following General Procedure:

In this method, we need to calculate the volume of the bar. We know, a steel bar that looks like a solid cylinder

The volume of steel bar(V) = A × h = πr2 × h.

Where ‘A’ is the area of the base, ‘h’ is the height/length of the bar, and r is the radius of the bar. [ r = d/2, where, ‘d’ is the dia of the bar].

We know, the density of the bar is (γ) = 7850 kg/m3

Therefore, the weight of steel bar = Volume of the bar × Density of bar = πr2h × γ.

Example 1: Let’s assume the dia of a bar is 8 mm, and length is 3 m.

• r = d/2 = 8/2 = 4 mm.
• h = 3 m.
• A = πr2 = π(4)2 = 50.26 mm2 = 5.026 × 10-5 m2.
• V = A × h = 5.026 × 10-5 × 3 = 1.507 × 10-4 m3.

The weight of the bar = V × γ = 1.507 × 10-4 × 7850 =1.18 kg.

Example 2: Let’s assume the dia of bar 12 mm and length is 3 m.

• r = d/2 = 12/2 = 6 mm.
• h = 3 m.
• A = πr2 = π(6)2 = 113.097 mm2 = 1.1309 × 10-4 m2.
• V = A × h = 1.1309 × 10-4 × 3 = 3.3929 × 10-4 m3.

The weight of the bar = V × γ = 3.3929 × 10-4 × 7850 = 2.66 kg.