W8×35 vs W8×40
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W8×40 is the heavier section at 40 lb per foot, versus 35 for W8×35 (5 lb/ft more).
Both are nominally 8 in. deep.
W8×40 has the greater bending strength: section modulus Sx of 35.5 in³ versus 31.2, about 14% more.
| Property | W8×35 | W8×40 |
|---|---|---|
| Weight | 35 lb/ft | 40 lb/ft |
| Depth (d) | 8 1/8" | 8 1/4" |
| Flange width (bf) | 8" | 8 1/8" |
| Web thickness (tw) | 5/16" | 3/8" |
| Flange thickness (tf) | 1/2" | 9/16" |
| Area (A) | 10.3 in² | 11.7 in² |
| Moment of inertia (Ix) | 127 in⁴ | 146 in⁴ |
| Section modulus (Sx) | 31.2 in³ | 35.5 in³ |
| Plastic modulus (Zx) | 34.7 in³ | 39.8 in³ |
Open W8×35 in the interactive size chart →
Full detail: W8×35 · W8×40. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
Browse more: size comparisons · Steel Beam Size Chart