W40X278 Steel Beam — Section Properties

Dimensions

Property Value Unit
Depth (d) 40.20 in (1021.1 mm)
Flange Width (bf) 12 in (304.8 mm)
Flange Thickness (tf) 1.81 in
Web Thickness (tw) 1.03 in
Area (A) 82.30 in² (531.0 cm²)
Weight 278 lb/ft (414 kg/m)

Elastic Section Properties

Property Strong Axis (X-X) Weak Axis (Y-Y) Unit
Moment of Inertia (I) 20,500 521 in⁴
Elastic Section Modulus (S) 1,020 87.10 in³
Plastic Section Modulus (Z) 1,190 140 in³
Radius of Gyration (r) 15.80 2.52 in

Torsional Properties

Property Value Unit
Torsional Constant (J) 65 in⁴
Warping Constant (Cw) 192,000 in⁶
Distance Between Flange Centroids (ho) 38.40 in
Effective Radius (rts) 3.13 in

Design Resources

Frequently Asked Questions

What is the weight of a W40X278 beam? 278 lb/ft (414 kg/m). A 40-ft length weighs approximately 11,120 lbs.

What is the section modulus of W40X278? Sx = 1020 in³ (strong axis) and Sy = 87.1 in³ (weak axis). The plastic section modulus Zx = 1190 in³ and Zy = 140 in³.

What steel grade is standard for W40X278? Typically ASTM A992 (Fy = 50 ksi, Fu = 65 ksi) for W-shapes. Also available in A572 Grade 50 or A36. Verify with mill certificate.

What is the moment of inertia of W40X278? Ix = 20500 in⁴ about the strong axis and Iy = 521 in⁴ about the weak axis. The radius of gyration is rx = 15.80 in and ry = 2.52 in.

Related Pages


Educational reference only. Verify all section properties against the current AISC Manual and mill certificates before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.