W40×277 vs W40×278
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W40×278 is the heavier section at 278 lb per foot, versus 277 for W40×277 (1 lb/ft more).
Both are nominally 40 in. deep.
W40×277 has the greater bending strength: section modulus Sx of 1100 in³ versus 1020, about 8% more.
| Property | W40×277 | W40×278 |
|---|---|---|
| Weight | 277 lb/ft | 278 lb/ft |
| Depth (d) | 39 3/4" | 40 1/8" |
| Flange width (bf) | 15 7/8" | 12" |
| Web thickness (tw) | 13/16" | 1" |
| Flange thickness (tf) | 1 9/16" | 1 13/16" |
| Area (A) | 81.5 in² | 82.3 in² |
| Moment of inertia (Ix) | 21900 in⁴ | 20500 in⁴ |
| Section modulus (Sx) | 1100 in³ | 1020 in³ |
| Plastic modulus (Zx) | 1250 in³ | 1190 in³ |
Open W40×277 in the interactive size chart →
Full detail: W40×277 · W40×278. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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