MB 300 (ISMB 300)

I-beam — 46.02 kg per metre, 58.6 cm² cross-sectional area. IS 808 Table 1 - Medium & Wide Flange Beams.

zyB 140D 300T 13.1R2 7R1 14t 7.7
Mass per metre
46.02kg/m
Sectional area
58.6cm²
Depth
300mm
Width
140mm

Medium & Wide Flange Beams (MB, WB). Reproduced as printed in IS 808 Table 1 - Medium & Wide Flange Beams.

MB 300 section properties

As printed in IS 808 Table 1 - Medium & Wide Flange Beams. 300 mm deep, 140 mm wide. Units are shown on every row, because the two standards on this site use different ones for the radius of gyration.

Dimensions

Depth of section D 300 mm
Width of flange B 140 mm
Thickness of web t 7.7 mm
Thickness of flange T 13.1 mm
Flange slope 98 °
Root radius R1 14 mm
Toe radius R2 7 mm

Mass and area

Mass per metre M 46.02 kg/m
Sectional area A 58.6 cm²

Major axis (z-z)

Second moment of area Izz 8,990 cm⁴
Radius of gyration rzz 123 mm
Elastic section modulus Zzz 599 cm³
Plastic section modulus Zpz 681 cm³

Minor axis (y-y)

Second moment of area Iyy 486 cm⁴
Radius of gyration ryy 28.7 mm
Elastic section modulus Zyy 69.4 cm³
Plastic section modulus Zpy 117 cm³

Torsion and warping

Torsion constant (St Venant) It 34.7 cm⁴
Warping constant Iw 1,23,000 cm⁶

What a length of MB 300 weighs

Total weight is the mass per metre multiplied by the length and the number of pieces. Ten pieces of MB 300 at six metres each is 46.02 × 6 × 10 = 2,761 kg. There is nothing else to it — the standard publishes the mass, so no one needs to compute it from the area.

You can check that mass against the area on this page: 58.6 cm² of steel at 7 850 kg/m³ is 46 kg/m. Every row in this dataset was checked that way, which is how the contradictions flagged on some of these pages were found.

Work it out for your own lengths and quantities →

Common questions about MB 300

What is the weight of MB 300 per metre?

IS 808 : 2021 gives MB 300 a mass of 46.02 kg per metre. Its printed cross-sectional area of 58.6 cm² agrees: 58.6 cm² of steel at 7 850 kg/m³ works out at 46.00 kg per metre.

How much does a 6 m length of MB 300 weigh?

276.12 kg. Mass per metre times length: 46.02 × 6. Ten such pieces come to 2761 kg.

Is MB 300 the same as ISMB 300?

It is the same section under the name IS 808 : 2021 gives it — the 2021 revision of IS 808 dropped the "IS" prefix, so a drawing saying ISMB 300 means this section. Check the edition before assuming the figures match, though: this page publishes the current tables, and a great many tables in circulation were copied from the 1989 edition.

What are the dimensions of MB 300?

300 mm deep and 140 mm wide, with a 7.7 mm web and 13.1 mm flanges.

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Where these figures come from. IS 808 Table 1 - Medium & Wide Flange Beams Section properties are facts published in the standards, and they are reproduced here as printed. Where a standard contradicts itself, both of its figures are shown and neither is corrected.

What is ours. The selection and arrangement of these tables, the checks run against them, and the findings those checks produced — which rows disagree with themselves, which figures were superseded by amendment, and which could not be read — are QuickBOQ’s work, and so is this wording. Quote the numbers freely; they belong to everyone. Copying the compilation and the commentary is a different thing, and we would rather you linked to it.