W 551 x 181,3 British Steel · Weight & Dimensions

British Steel, hot-rolled sections · Wide Flange (I-beam)

Wide flange beams (W shapes / I-beams) are the most common structural steel profile used in building construction. They are used for beams, columns, and girders in steel-framed buildings and bridges. Designed per AISC 360, Eurocode 3, and NBR 8800.

Also known as: IPR 551 x 181,3 (México) · Doble T 551 x 181,3 (Argentina / LATAM) · UB 550.7 (UK / Australia)

The W 551 x 181,3 steel profile weighs 181.3 kg/m (121.86 lb/ft), has a depth of 550.7 mm (21.68 in), flange width 314.5 mm (12.38 in). Cross-sectional area: 23,114.933 mm². Moment of inertia Ix = 123,222.001 cm⁴, Iy = 12,666.566 cm⁴.

Cross-section (not to scale)

Dimensions

Property	Metric	Imperial
Depth (h)	550.7 mm	21.68 in
Width (b)	314.5 mm	12.38 in
Web thickness (tw)	15.2 mm	0.60 in
Flange thickness (tf)	24.4 mm	0.96 in
Fillet radius (r)	12.7 mm	0.50 in
Weight	181.3 kg/m	121.86 lb/ft

Section Properties

Property	Metric	Imperial
Area (A)	23,114.93 mm²	35.828 in²
Moment of inertia (Ix)	123,222 cm⁴	2960.41 in⁴
Moment of inertia (Iy)	12,666.57 cm⁴	304.31 in⁴
Elastic section modulus (Sx)	4,475.1 cm³	273.089 in³
Elastic section modulus (Sy)	805.5 cm³	49.155 in³
Plastic section modulus (Zx)	5,030.31 cm³	306.969 in³
Plastic section modulus (Zy)	1,237.14 cm³	75.495 in³
Radius of gyration (rx)	23.09 cm	9.090 in
Radius of gyration (ry)	7.4 cm	2.914 in