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350x350x12.5SHS Square Hollow Section

AS/NZS 1163Grade C450L0

The 350x350x12.5SHS is a square hollow section to AS/NZS 1163. It is 350 × 350 mm with a 12.5 mm wall, has a mass of 128.0 kg/m and a gross area of 16338 mm². Its major-axis second moment of area is Ix = 305 × 10⁶ mm⁴ and in Grade C450L0 (fy = 450 MPa) its section moment capacity is φMsx = 767.8 kNm. Download its free DXF drawing (a true-scale CAD outline) below, or print the dimensioned drawing sheet.

Also written as: 350 x 350 x 12.5 SHS, 350x350x12.5 SHS

DXF (AutoCAD R12)SVG drawingJSON data
350x350x12.5SHS Square Hollow Section cross-section drawingxxyyd = 350b = 350t = 12.5ro = 31.2NOTES1. ALL DIMENSIONS IN MILLIMETRES. TRUE SCALE 1:5 WHEN PRINTED ON A4.2. x-x, y-y: CENTROIDAL (PRINCIPAL) AXES.3. VERIFY AGAINST MANUFACTURER DATA BEFORE USE.STEELINFOSTEELINFO.AUTITLE350x350x12.5SHS SQUARE HOLLOW SECTIONSTANDARDAS/NZS 1163GRADEC450L0SCALE @ A41:5UNITSmmDATE2026-10-08

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Dimensions

350x350x12.5SHS dimensions
SymbolPropertyValueUnit
dDepth350mm
bWidth350mm
tWall thickness12.5mm
roExternal corner radius (used for properties)31.2mm

Section properties

350x350x12.5SHS section properties
SymbolPropertyValueUnit
mMass per metre (nominal)128.0kg/m
AgGross cross-section area16338mm²
IxSecond moment of area about x-axis30510⁶ mm⁴
ZxElastic section modulus, x-axis174110³ mm³
SxPlastic section modulus, x-axis204410³ mm³
rxRadius of gyration, x-axis136.6mm
IySecond moment of area about y-axis30510⁶ mm⁴
ZyElastic section modulus, y-axis174110³ mm³
SyPlastic section modulus, y-axis204410³ mm³
ryRadius of gyration, y-axis136.6mm
JTorsion constant49250810³ mm⁴
CTorsion modulus264810³ mm³
AsExternal surface area per metre1.346m²/m
As/tExternal surface area per tonne10.5m²/t

Axes: x-x is the major axis and y-y the minor axis, both through the centroid.

Mass 768.0 kg · surface area 8.08 m²

Design capacities to AS 4100

AS 4100 design capacities – Grade C450L0
SymbolPropertyValueUnit
Steel gradeC450L0 (AS/NZS 1163)
fyYield stress used450MPa
fuTensile strength500MPa
kfForm factor (Cl. 6.2.2)1.000
Section class, x-axis (Cl. 5.2)Non-compact
ZexEffective section modulus, x-axis189610³ mm³
φMsxSection moment capacity, x-axis767.8kNm
Section class, y-axisNon-compact
ZeyEffective section modulus, y-axis189610³ mm³
φMsySection moment capacity, y-axis767.8kNm
φNsSection compression capacity (Cl. 6.2.1)6617kN
φNtTension capacity, gross section (Cl. 7.2, kt=1, An=Ag)6249kN
φVvShear capacity (Cl. 5.11)1974kN
αbCompression member section constant (Table 6.3.3)-0.5
Member capacity vs effective length (αm = 1.0)
Le (m)φNcx (kN)φNcy (kN)
0.566176617
166176617
1.566046604
265486548
2.564856485
364136413
3.563306330
462366236
560136013
657375737
754015401
849994999
945424542
1040584058
1231523152

φNc: Cl. 6.3.3, pin-ended effective length Le = keL, concentric load.

714657174288285914290024681012Effective length Le (m)
φNcx (kN)φNcy (kN)
Member capacity calculator

Check it for a span and loads with the beam calculator.

For restraint types, ktklkr and αm, use the lateral restraint calculator.

Instant check only. Effective lengths and moment modification factors must be determined by the designer in accordance with AS 4100 Cl. 4.6, 5.6.3 and 6.3.2. Not a substitute for a qualified engineer: see the disclaimer.

Alternatives with similar bending capacity

Sections from other families with a plastic modulus Sx within −8% / +25% of the 350x350x12.5SHS, lightest first.

SectionTypeMass (kg/m)Sx (10³ mm³)Ix (10⁶ mm⁴)
530UB82.0Universal Beam82.02066477
530UB92.4Universal Beam92.42371554
457.0x9.5CHSCircular Hollow Section105.01903334
508.0x9.5CHSCircular Hollow Section117.02361462
310UC118Universal Column118.01962278
406.4x12.7CHSCircular Hollow Section123.01969305

Other square hollow sections

Relevant Australian Standards

See all Australian Standards for structural steel.

Properties are calculated from nominal dimensions, including root and toe radii, as described in notation & method. Mass is the nominal catalogue mass; the calculated mass at 7850 kg/m³ is 128.26 kg/m. Verify against current manufacturer literature before use in design. Spotted an error? Report it.