Changing Section Properties

To change the value of a property stored with a section

§ Click on the property to be changed

§ Type in a new value

§ Press the Enter key

When you change the properties of a section, you must use the units indicated at the top of the column for the property displayed in that column of the table. The standard properties stored in a group are

Name	Property	Metric	English
Mass	Mass per unit length	kg/m	lb/ft
A	Cross sectional area	mm²	in²
Ix	Major moment of inertia	mm⁴	in⁴
Iy	Minor moment of inertia	mm⁴	in⁴
J	Torsion constant	mm⁴	in⁴
E	Young's Modulus	MPa	ksi
G	Shear Modulus	MPa	ksi
D	Depth	mm	in
B	Breadth or Width	mm	in
tf	Flange thickness	mm	in
tw	Web thickness	mm	in
fy	Yield Strength	MPa	ksi
fu	Ultimate Strength	MPa	ksi
Sxt (or Zxt)	Elastic Modulus about x at top	mm³	in³
Sxb (or Zxb)	Elastic Modulus about x at bottom	mm³	in³
Sxt (or Zxt)	Elastic Modulus about x at top	mm³	in³
Syl (or Zyl)	Elastic Modulus about y at left	mm³	in³
Syr (or Zyr)	Elastic Modulus about y at right	mm³	in³
rx	radius of gyration about x	mm	in
ry	radius of gyration about y	mm	in
Sx (or Zx)	Plastic Modulus about x	mm³	in³
Sy (or Zy)	Plastic Modulus about y	mm³	in³
Iw	Warping constant	mm³	in³
rz	radius of gyration about weakest axis	mm	in
Asx	Shear area in weak axis direction (x)	mm²	in²
Asx	Shear area in strong axis direction (y)	mm²	in²
b1,b2	Additional width dimensions required for some section shapes. (e.g. Width of Zed flanges)	mm	in
d1,d2	Additional width dimensions required for some section shapes. (e.g. Depth of lip for Cee or Zed sections)	mm	in
b2	Width of bottom Zed flange	mm	in
d1	Depth of lip of Cee or Zed shape	mm	in
D2	Depth of lip of Cee or Zed shape	mm	in
xc, yc	Position of centroid as measured for bottom left hand corner of section	mm	in
Ø	Angle of principle axes from section axes.	degrees	degrees
Iu	Moment of inertia about major principle axis.	mm⁴	in⁴
Iv	Moment of inertia about minor principle axis.	mm⁴	in⁴
Ru	Radius of gyration about major principle axes	mm	in
Rv	Radius of gyration about minor principle axes	mm	in
Sut or Zut	Elastic Modulus about major principle axes in positive v axis direction.	mm³	in³
Sub or Zub	Elastic Modulus about major principle axes in negative v axis direction.	mm³	in³
Svt or Zvt	Elastic Modulus about minor principle axes in positive u axis direction.	mm³	in³
Svb or Zvb	Elastic Modulus about minor principle axes in negative u axis direction.	mm³	in³
xs, ys	Position of shear centre as measure from centroid.	mm	in
P	Perimeter of section	mm	in
Tan(Ø)	Tan of principle axis angle
s	Spacing parameter	mm	in
r1	Primary radii (e.g. Fillet radius)	mm	in
r2	Secondary radii (e.g. Toe radius)	mm	in
Ixy	Product of Inertia	mm⁴	in⁴

The following diagram will help you determine the dimensional properties. These properties are used by Multiframe for rendering and display of member details and stresses and by Section Maker for placing standard shapes and existing sections.