The UA 125×75×8 is a steel section with a mass of 12.2 kg/m, an overall depth of 125 mm and width of 75 mm. It has a cross-sectional area of 15.5 cm², a second moment of area Iᵧ of 249 cm⁴, an elastic modulus Wₑₗ,ᵧ of 29.7 cm³, tabulated by CivilAxis from EN 10056 · Continental Steel.
Mass
12.2 kg/m
Depth
125 mm
Width
75 mm
Area
15.5 cm²
Ask about capacity, buckling or detailing for UA 125×75×8.
Dimension symbols for Unequal Angle sections. Not to scale.
UA 125×75×8 section properties to EN 10056 · Continental Steel.
Geometry
Depth of section
h
125
Width of section
b
75
Web thickness
tw
8
Flange thickness
tf
8
Root fillet radius
r
11
Toe radius
r2
4.8
Mass and area
Mass per metre
mass
12.2
Cross-sectional area
A
15.5
Bending about the major axis (y-y)
Area moment of inertia about y-axis
Iy
249
Elastic section modulus about y-axis
Wel,y
29.7
Radius of gyration about y-axis
iy
4
Bending about the minor axis (z-z)
Area moment of inertia about z-axis
Iz
68.1
Elastic section modulus about z-axis
Wel,z
11.7
Radius of gyration about z-axis
iz
2.1
Principal axes
Area moment of inertia about u-u (major principal) axis
Iu
275
Area moment of inertia about v-v (minor principal) axis
Iv
41.3
Radius of gyration about u-u axis
iu
4.21
Radius of gyration about v-v axis
iv
1.63
Elastic section modulus about u-u axis
Wel,u
29.7
Elastic section modulus about v-v axis
Wel,v
11.7
Detailing dimensions
Centroid distance from back of leg (y)
cy
4.14
Centroid distance from back of leg (z)
cz
1.69
Common questions about UA 125×75×8
UA 125×75×8 has a mass of 12.2 kg/m, tabulated to EN 10056. A 12 m length therefore weighs about 146 kg, which is the figure to use for a steel take-off or when checking a lift.
UA 125×75×8 has a depth of 125 mm, a width of 75 mm, a web thickness of 8 mm, a flange thickness of 8 mm, with a cross-sectional area of 15.5 cm². These are the nominal dimensions from EN 10056; rolling tolerances apply to the delivered section.
The elastic section modulus about the major axis, Wel,y, is 29.7 cm³. Angles are tabulated about their principal (u-u and v-v) axes rather than a plastic major-axis modulus, so the elastic value is the one to design from unless you are working from the principal-axis properties directly.
The second moment of area about the major axis, Iy, is 249 cm⁴, and about the minor axis Iz is 68.1 cm⁴. Iy is the value deflection depends on - for a simply supported beam under a uniform load, the midspan deflection is 5wL⁴/384EIy - so on spans where a deflection limit governs rather than strength, this is the number that decides the section.
iy is 4 cm about the major axis and iz is 2.1 cm about the minor axis. Column buckling is governed by the SMALLER value: the slenderness is lambda = L_cr / i, so with iz = 2.1 cm a 0.2 m effective length already gives lambda = 100. Minor-axis buckling almost always controls unless the weak axis is restrained.
