Channel Sections: Mass of 1 m, Dimensions and Section Properties

Channels No. 5–40: dimensions and mass of 1 m

The channel number equals its height in centimetres, so a No. 20 channel is 200 mm high. The letter “a” in the number, as in 16a, marks a profile of the same height with a wider flange.

The U and P series differ in the shape of the flanges. In the U series the inner flange faces are sloped, in the P series they are parallel. The table below gives the dimensions and the mass of 1 m for both series in a single row.

Hot-rolled steel channels (U and P series) · ГОСТ 8240-89

h is the height, b the flange width, s the web thickness and t the mean flange thickness, all in millimetres. The mass of 1 m assumes steel of 7850 kg/m³.

Section properties

To check a channel in bending or compression you need the section area and the moments of inertia and resistance. The values are given for the U series of the DSTU 3436-96 range, from 6.5U to 30U.

Look separately at y0. It is the distance from the web axis to the centroid of the section: a channel is not symmetrical, so its centroid sits toward the web, and this offset matters when the channel acts as a column or carries a load from the side.

Hot-rolled steel channels (U series) · ДСТУ 3436-96

A is the section area. About the y–y axis, parallel to the web: Jy is the moment of inertia, Wy the section modulus, iy the radius of gyration and Sy the first moment of half the section. Jz, Wz, iz are the same quantities about z–z. y0 is the distance from the web axis to the centroid.

Hole positions · Hot-rolled steel channels (U series)

Holes in the flange (a1, d1 max) and in the web (a2, d2 max): a is the distance to the hole axis, d max the largest diameter. Reference data.

How to get the mass of a channel from the table

The mass is the mass per metre times the length. A No. 20 channel weighs 18.4 kg/m, so a six-metre piece is 110 kg, and a tonne of this section is about 54 m long.

No. 30 has 31.8 kg per metre, so six metres give 191 kg. When you buy by weight, use the “Metres per tonne” column: divide the length by that number to get tonnes.

Where channels are used

A channel works well in bending in the plane of the web, so it is used for purlins and for frame and lintel beams. Two channels set flange to flange or back to back make a column. Channels also go into truss chords and into frames under equipment.

Calculator and ordering

Use the rolled metal calculator to weigh a whole batch of channels. The other sections are collected in the rolled metal handbook. If you need the channels as part of a structure, send a drawing or a specification: the POLYGONAL company makes steel structures to the customer’s drawings and galvanizes the products.