**What is D^2/162 and D^2/533 and their derivation in civil engineering,****What is Unit Weight of Steel in kg / feet,**hi guys in this article we know about what is D^2/162 and D^2/533 and their derivation in civil engineering and what is Unit Weight of Steel in **Kg per meter and kg per foot**.

When we have any project related with construction of building we have required quantity of steel bar and how we know quantity of steel bar in KG per feet and kg/ m according to designing and their requirement for various purpose in construction use like formation of mesh bar, ground footing ,column formation, Foundation work, plinth beam ,tie beam, lintel beam, wall beam and casting of roof slab and other rcc structure.

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**Various type of steel structure member in civil engineering**

In civil construction work various type of steel structure member is used like round bar ,MS bar, MS plate, MS angle ,MS channel, i-type beam, H-type beam , S-type beam, rectangular Steel solid bar, rectangular hollow Steel bar, square Steel solid bar, square shaped hollow Steel bar and others and for all these structure question is arises in our mind how we calculate Unit Weight of these type of Steel bar in KG per feet. So let us discuss about derivation of their formula D^2/533 in kg /ft and D^2/162 kg/m.

**Derivation of formula D^2/162 and D^2/533**

First we should derive formula D^2/162 than D^2/533

**1) D^2/162 is formula used for the Unit Weight calculation of Steel bar in KG per metre**

**2) D^2/533 is formula used for the Unit Weight calculation of Steel bar in KG per feet**

Consider unit Length of steel = 1 meter

Density of steel = 7850 kg/m3

Weight of steel = Volume × density

Volume = cross sectional Area × Length

Volume = (πD^2/4) mm2 × 1m

1meter = 1000 millimeter

1mm = 1/1000 meter

1mm2 = 1/(1000)^2 m2 and value of π =3.14 putting both this value

Volume = (3.14/4×1000000) D^2 m2 ×1m

Weight = Volume × density

Weight = (3.14/4×1000000) D^2 m2 ×1m × 7850 kg/m3

Weight = (24649/4000000) D^2 Kg

Weight = 0.00616225 × D^2 Kg

This can be written also as

Weight = (D^2/1/0.00616225 ) kg

Where value of 1/0.00616225 =162.27

Hence weight = D^2/162 kg/m

1) so unit weight formula steel weight calculation in Kilogram per metre is D^2/162 kg/m

2) now thus we derives formula for Unit Weight calculation of Steel in Kilogram per feet

We know 1 meter = 3.28 foot

So we have

Weight = D^2/(162×3.28) kg/foot

Weight steel formula = D^2/533 kg/ft

D^2/533 kg/ft is formula for Unit Weight calculation of Steel in Kilogram per feet

**What is Unit Weight of Steel in kg / m and kg/ft**

**Q1) how to calculate Unit Weight of 8mm Steel bar in kg/m and kg/ft**

Given size of steel = 8 mm

A) unit weight in kg/m

Unit weight =( D^2/162) L kg/m

Unit weight = (8×8)/162 kg/m

Unit weight = 0.395 kg/m

B) unit weight in kg/ft

Unit weight =( D^2/533) L kg/ft

Unit weight = (8×8)/533 kg/ft

Unit weight = 0.12 kg/ft

**Q2) how to calculate Unit Weight of 10mm Steel bar in kg/m and kg/ft**

Given size of steel = 10 mm

A) unit weight in kg/m

Unit weight =( D^2/162) L kg/m

Unit weight = (10×10)/162 kg/m

Unit weight = 0.617 kg/m

B) unit weight in kg/ft

Unit weight =( D^2/533) L kg/ft

Unit weight = (10×10)/533 kg/ft

Unit weight = 0.188 kg/ft

**Q3) how to calculate Unit Weight of 12mm Steel bar in kg/m and kg/ft**

Given size of steel = 12 mm

A) unit weight in kg/m

Unit weight =( D^2/162) L kg/m

Unit weight = (12×12)/162 kg/m

Unit weight = 0.889 kg/m

B) unit weight in kg/ft

Unit weight =( D^2/533) L kg/ft

Unit weight = (12×12)/533 kg/ft

Unit weight = 0.27 kg/ft

**Q4) how to calculate Unit Weight of 16mm Steel bar in kg/m and kg/ft**

Given size of steel = 16 mm

A) unit weight in kg/m

Unit weight =( D^2/162) L kg/m

Unit weight = (16×16)/162 kg/m

Unit weight = 1.58 kg/m

B) unit weight in kg/ft

Unit weight =( D^2/533) L kg/ft

Unit weight = (16×16)/533 kg/ft

Unit weight = 0.48 kg/ft

**Q5) how to calculate Unit Weight of 20mm Steel bar in kg/m and kg/ft**

Given size of steel = 20 mm

A) unit weight in kg/m

Unit weight =( D^2/162) L kg/m

Unit weight = (20×20)/162 kg/m

Unit weight = 2.47 kg/m

B) unit weight in kg/ft

Unit weight =( D^2/533) L kg/ft

Unit weight = (20×20)/533 kg/ft

Unit weight = 0.75 kg/ft

**Q6) how to calculate Unit Weight of 25mm Steel bar in kg/m and kg/ft**

Given size of steel = 25 mm

A) unit weight in kg/m

Unit weight =( D^2/162) L kg/m

Unit weight = (25×25)/162 kg/m

Unit weight = 3.86 kg/m

B) unit weight in kg/ft

Unit weight =( D^2/533) L kg/ft

Unit weight = (25×25)/533 kg/ft

Unit weight = 1.173 kg/ft