I-beam — 41.5 kg per metre, 52.8 cm² cross-sectional area. IS 808 Table 2 - Light/Junior Beams.
Light & Junior Beams (LB, JB). Reproduced as printed in IS 808 Table 2 - Light/Junior Beams.
Provisional section
As printed in IS 808 Table 2 - Light/Junior 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.
| Depth of section D | 300 | mm |
|---|---|---|
| Width of flange B | 140 | mm |
| Thickness of web t | 7 | mm |
| Thickness of flange T | 11.6 | mm |
| Flange slope | 98 | ° |
| Root radius R1 | 15 | mm |
| Toe radius R2 | 7.5 | mm |
| Mass per metre M | 41.5 | kg/m |
|---|---|---|
| Sectional area A | 52.8 | cm² |
| Second moment of area Izz | 8,140 | cm⁴ |
|---|---|---|
| Radius of gyration rzz | 124 | mm |
| Elastic section modulus Zzz | 542 | cm³ |
| Plastic section modulus Zpz | 614 | cm³ |
| Second moment of area Iyy | 414 | cm⁴ |
|---|---|---|
| Radius of gyration ryy | 27.9 | mm |
| Elastic section modulus Zyy | 59.2 | cm³ |
| Plastic section modulus Zpy | 101 | cm³ |
| Torsion constant (St Venant) It | 26.3 | cm⁴ |
|---|---|---|
| Warping constant Iw | 1,10,000 | cm⁶ |
Total weight is the mass per metre multiplied by the length and the number of pieces. Ten pieces of LB(P) 300 at six metres each is 41.5 × 6 × 10 = 2,490 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: 52.8 cm² of steel at 7 850 kg/m³ is 41.45 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 →
IS 808 : 2021 gives LB(P) 300 a mass of 41.5 kg per metre. Its printed cross-sectional area of 52.8 cm² agrees: 52.8 cm² of steel at 7 850 kg/m³ works out at 41.45 kg per metre.
249.00 kg. Mass per metre times length: 41.5 × 6. Ten such pieces come to 2490 kg.
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 ISLB(P) 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.
300 mm deep and 140 mm wide, with a 7 mm web and 11.6 mm flanges.
Free to browse. Log in to unlock the full Rate Analysis of every Civil and Electrical item in the latest CPWD DSR.
Log in to QuickBOQ →Where these figures come from. IS 808 Table 2 - Light/Junior 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.