HSS18×18×5/8 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.

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

At 144.39 lb per foot it is one of the 8 HSS18×18 sizes, which run from 59.85 to 222.63 lb/ft.

For strong-axis bending its section modulus is Sx = 220 in³ and its moment of inertia Ix = 1980 in⁴, with a plastic modulus Zx = 257 in³.

Detailing dimensions

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

Section properties

Weight144.39 lb/ft
Area (A)39.6 in²
Ix1980 in⁴
Sx220 in³
Zx257 in³
rx7.07 in
Iy1980 in⁴
Sy220 in³
Zy257 in³
ry7.07 in
J3120 in⁴

Other HSS18×18 sizes

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

HSS18×18×1/4HSS18×18×5/16HSS18×18×3/8HSS18×18×1/2HSS18×18×3/4HSS18×18×7/8HSS18×18×1

All HSS18×18 sizes and dimensions →

Similar weight HSS shapes

Comparable 144.39 lb/ft sections in other HSS tube sizes.

HSS24×12×5/8144.39 lb/ft · Sx 245 in³HSS22×14×5/8144.39000000000001 lb/ft · Sx 240 in³HSS20×16×5/8144.39000000000001 lb/ft · Sx 232 in³HSS24×20×1/2144.13 lb/ft · Sx 287 in³HSS22×22×1/2144.13 lb/ft · Sx 276 in³HSS22.000×0.625142.81 lb/ft · Sx 204 in³HSS28.000×0.500146.99 lb/ft · Sx 272 in³HSS16.000×0.875141.48 lb/ft · Sx 140 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 HSS18×18×5/8 cut, formed, or fabricated? Huntington Steel & Supply Co.

Browse more: HSS tube · Steel Beam Size Chart

Interactive drawing