SECTIONAL PROPERTIES CALCULATOR  RECTANGULAR HOLLOW STRUCTURAL SECTIONS (TUBES)
Hollow structural sections are metal profiles with square or rectangular tube
section. They are also known as rectangular steel tubes. ASTM A500 is the most
common steel specification for hollow structural section in North America. This
specification is for cold formed welded and seamless carbon steel tubing in
round, square and rectangular shapes. ASTM A501 is another standard for hot
formed steel tubing. Hollow rectangular sections are used in structural
applications such as structural supports and building columns.
The following calculator has been developed to calculate the sectional
properties of structural hollow rectangular sections (tubes).
Calculator:
OUTPUT PARAMETERS 
Parameter 
Symbol 
Value 
Unit 
Cross section area (A) 
A 



Mass (M) 
M 



Second moment of area (Ixx) 
I_{xx} 



Second moment of area (Iyy) 
I_{yy} 


Section modulus (Sxx) 
S_{xx} 



Section modulus (Syy) 
S_{yy} 


Radius of gyration (rx) 
r_{x} 



Radius of gyration (ry) 
r_{y} 


CoG distance in x direction (xcog) 
x_{cog} 



CoG distance in y direction (ycog) 
y_{cog} 


Note: Use dot "." as decimal separator.
Definitions:
Radius of Gyration (Area): The
capacity of a crosssection to resist bending.
Second Moment of Area: The
distance from an axis at which the area of a body may be assumed to be
concentrated and the second moment area of this configuration equal to the
second moment area of the actual body about the same axis.
Section Modulus: The moment of
inertia of the area of the cross section of a structural member divided by the
distance from the center of gravity to the farthest point of the section; a
measure of the flexural strength of the beam.
Supplements:
List of Equations:
HOLLOW RECTANGLE 

Step 
Parameter/Condition 
Symbol 
Equation 
1 
Cross section area 
A 
A = BHbh 
2 
Area moment of inertia 
I_{xx} 
I_{xx} = BH^{3}/12  bh^{3}/12 
3 
Area moment of inertia 
I_{yy} 
I_{yy} = HB^{3}/12  hb^{3}/12 
4 
Section modulus 
S_{xx} 
S_{xx} = I_{xx}/y_{cog} 
5 
Section modulus 
S_{yy} 
S_{yy} = I_{yy}/x_{cog} 
6 
Center of gravity 
x_{cog} 
x_{cog}=B/2 
7 
Center of gravity 
y_{cog} 
y_{cog}=H/2 
8 
Mass 
M 
M = ALρ 
9 
Radius of gyration 
r 
r = (I/A)^0.5 
10 
Polar moment of inertia 
J 
J = I_{xx} + I_{yy} 
Reference:

Oberg, E., Jones, F. D., Horton, H. L., & Ryffel, H. H. (2012) .
Machinery's Handbook
. 29th edition. Industrial Press Inc., pp 234  256