CivilAxisCivilAxis
/Tools › Steel Sections
☕ Support🌐 Community

RHS 350×150×16 - Section Properties

The RHS 350×150×16 is a rectangular hollow section with a mass of 115 kg/m, an overall depth of 350 mm and width of 150 mm and a wall thickness of 16 mm. It has a cross-sectional area of 147 cm², a second moment of area Iᵧ of 21100 cm⁴, a plastic modulus Wₚₗ,ᵧ of 1560 cm³, tabulated by CivilAxis from BS EN 10210-2:2006 (SCI P363 Blue Book).

Mass
115 kg/m
Depth
350 mm
Width
150 mm
Wall thickness
16 mm
Area
147 cm²
Ask about capacity, buckling or detailing for RHS 350×150×16.
🔍 Open the full Steel Catalogue →📖 Design theory📐 Worked example
or pick a unit on any row
RHS Hot-finished section profile showing the dimension symbols used for RHS 350×150×16

Dimension symbols for RHS Hot-finished sections. Not to scale.

RHS 350×150×16 section properties to BS EN 10210-2:2006.

Geometry

Depth of sectionh350
Width of sectionb150
Wall thicknesst16

Mass and area

Mass per metremass115
Cross-sectional areaA147

Bending about the major axis (y-y)

Area moment of inertia about y-axisIy21100
Elastic section modulus about y-axisWel,y1210
Plastic section modulus about y-axisWpl,y1560
Radius of gyration about y-axisiy12

Bending about the minor axis (z-z)

Area moment of inertia about z-axisIz5320
Elastic section modulus about z-axisWel,z709
Plastic section modulus about z-axisWpl,z840
Radius of gyration about z-axisiz6.01

Torsion and warping

Torsion constant (St Venant)It14100
Section modulus for torsionWt1230

Classification and stability

Flange local-buckling ratiocf/tf6.38
Web local-buckling ratiocw/tw18.9

Surface area

Surface area per metreSA/m0.959
Surface area per tonneSA/t8.31m²/t

Is RHS 350×150×16 strong enough?

Simply supported beam, uniform load, major-axis bending - to EN 1993-1-1.

✅Passes - 62% utilised, deflection governs
Bending28%
156.2 / 553.8 kNm
Shear4%
89.3 / 2109.0 kN
Deflection62%
12.0 / 19.4 mm

Class 1 section. ULS uses γQ = 1.5 on the load you enter; deflection uses the unfactored load against L/360. Lateral-torsional buckling is not included - the compression flange is assumed restrained.

Common questions about RHS 350×150×16

RHS 350×150×16 has a mass of 115 kg/m, tabulated to BS EN 10210-2:2006. A 12 m length therefore weighs about 1380 kg, which is the figure to use for a steel take-off or when checking a lift.

RHS 350×150×16 has a depth of 350 mm, a width of 150 mm, a wall thickness of 16 mm, with a cross-sectional area of 147 cm². These are the nominal dimensions from BS EN 10210-2:2006; rolling tolerances apply to the delivered section.

The plastic section modulus about the major axis, Wpl,y, is 1,560 cm³, and the elastic modulus Wel,y is 1,210 cm³. Wpl,y is what sets the moment capacity of a Class 1 or 2 section: M_pl,Rd = Wpl,y x f_y / gamma_M0, so at S355 with gamma_M0 = 1.0 this section reaches about 554 kNm before any stability check.

The second moment of area about the major axis, Iy, is 21,100 cm⁴, and about the minor axis Iz is 5,320 cm⁴. Iy is the value deflection depends on - for a simply supported beam under a uniform load, the midspan deflection is 5wL⁴/384EIy - so on spans where a deflection limit governs rather than strength, this is the number that decides the section.

Its local-buckling ratios are cf/tf = 6.38 for the flange and cw/tw = 18.9 for the web. EN 1993-1-1 Table 5.2 compares these against limits scaled by epsilon = sqrt(235/f_y), so the class depends on the steel grade as well as the geometry - the same section can be Class 1 in S275 and Class 3 in S355. Use the Capacity tab on this page for the classification at a specific grade.

iy is 12 cm about the major axis and iz is 6.01 cm about the minor axis. Column buckling is governed by the SMALLER value: the slenderness is lambda = L_cr / i, so with iz = 6.01 cm a 0.6 m effective length already gives lambda = 100. Minor-axis buckling almost always controls unless the weak axis is restrained.

The St Venant torsion constant It is 14,100 cm⁴. Closed sections carry torsion in a shear flow around the perimeter, which makes them far stiffer in torsion than an open section of the same weight and is usually why one is specified.

Related RHS Hot-finished sizes

RHS 350×150×8.8RHS 350×150×10RHS 350×150×12.5RHS 350×150×14.2RHS 350×250×6.3RHS 350×250×7.1RHS 350×250×8RHS 350×250×8.8

Learn more

📘 How to read a steel section table (UB, UC, IPE, HE) →📘 Section modulus explained: elastic (Wel) vs plastic (Wpl) →📘 SHS vs RHS vs CHS: choosing a hollow steel section →
All RHS Hot-finished sizes →
Rectangular Hollow Sections - Hot-finished (BS EN 10210)
Full steel section tables →
Every UB, UC, hollow, channel & angle section
Open the interactive tool →
Search, compare & run EC3 capacity checks
Rate this
No ratings yet
Sign in to join the discussion.
Loading…