HSS18×8×5/16 square/rectangular HSS tube

Detailing dimensions and section properties from the AISC Shapes Database, 16th Edition. Values are shown to the nearest 1/16 in. as they appear on a shop drawing.

HSS18×8×5/16 is a rectangular tube 18 in. by 8 in. with a 5/16 in. nominal wall.

At 53.11 lb per foot it is one of the 5 HSS18×8 sizes, which run from 42.84 to 101.85000000000001 lb/ft.

For strong-axis bending its section modulus is Sx = 67.1 in³ and its moment of inertia Ix = 604 in⁴, with a plastic modulus Zx = 83.4 in³.

Detailing dimensions

Depth (Ht)18"
Width (B)8"
Nominal wall (t)5/16"

Section properties

Weight53.11 lb/ft
Area (A)14.6 in²
Ix604 in⁴
Sx67.1 in³
Zx83.4 in³
rx6.44 in
Iy172 in⁴
Sy43 in³
Zy47.5 in³
ry3.44 in
J432 in⁴

Other HSS18×8 sizes

Same nominal size, different weight — useful when you are checking a substitution or a lighter section.

HSS18×8×1/4HSS18×8×3/8HSS18×8×1/2HSS18×8×5/8

All HSS18×8 sizes and dimensions →

Similar weight HSS shapes

Comparable 53.11 lb/ft sections in other HSS tube sizes.

HSS20×6×5/1653.11 lb/ft · Sx 67.3 in³HSS16×10×5/1653.11 lb/ft · Sx 65.4 in³HSS14×12×5/1653.11 lb/ft · Sx 62.1 in³HSS24×8×1/453.050000000000004 lb/ft · Sx 84.4 in³HSS22×10×1/453.050000000000004 lb/ft · Sx 83.9 in³HSS16×16×1/453.050000000000004 lb/ft · Sx 75 in³HSS16×6×3/853 lb/ft · Sx 55.6 in³HSS14×8×3/853 lb/ft · Sx 54.6 in³

Detailing values are rounded to the nearest 1/16 in. per the AISC Steel Construction Manual. Verify critical dimensions against the current Manual before fabrication. Need HSS18×8×5/16 cut, formed, or fabricated? Huntington Steel & Supply Co.

Browse more: HSS tube · Steel Beam Size Chart

Interactive drawing