The document provides information on the moment and shear capacities of different ISMB steel beams, including their weights, dimensions, and maximum permissible stresses. It lists the moment and shear capacities in ton-meters and tons for ISMB beams ranging from 100-600 sizes. It also includes a table showing the effective lengths of beams for different unsupported lengths in meters. A note explains that the listed moment capacities assume full permissible bending stress, but the actual values depend on the unsupported length and permissible stresses in bending compression, which are provided in a table based on the lateral unsupported length.

1. Section
I Weight I Flange
Web
thick-
Momen
t
Shea
r
kg/m. thickness ness tw Capacit
y
capa
city
tf (mm) (mm) (ton-m) (ton)
ISMB
100
11.
5
7.2 4.0 0.85 4.0
150 14.
9
7.6 4.5 1-.6 7.2
200 25.
4
10.8 5.7 3.6 10.8
250 37.
3
12.5 6.9 6.7 16.3
300 44.
2
12.4 7.5 9.4 21.3
350 52.
4
14.2 8.1 12.8 26.8
400 61.
6
16.02 8.9 16.8 33.6
450 72.
4
17.4 9.4 22.2 40.0
500 86.
9
17.2 10.2 29.8 48.2
550 103
.7
19.3 11.2 38.9 58.0
600 122
.6
20.0 12.8 50.4 68.0
Unsupporte
Effective
Length (m) MB600 MB500 MB400 MB300 MB200 MB 100
1 1650 165 1650 1650 1650 1650
2 1650 165 1650 1650 1650 1650
3 1650 165 1526 1559 1382 1286
4 1650 148 1120 1182 1003 1009
5 1376 114 892 937 836 -6 1104 886 759 801 730 -
7 885 770 665 707 - -8 786 686 590 630 - -
9 703 611 - - - -
1 638 540 - - - -
1 573 - - - - -1
2
527 - - - - -
Permissible stresses in bending compression
Structural Steel Work 359 Section 8S.ntlnn 8 Structural Steel Wo358
8-22. MOMENT AND SHEAR CAPACITY OF BEAMS
Note: In any case, ratio of effective length to least radius of gyration in any
direction should not exceed 300 in case of bending members.
Note: The moment capacity mentioned above is based on assumption ~ that
full permissible bending stress is taken in calculation. However, ~
permissible bending stress in compression varies depending upon
unsupported length in the lateral direction. This is because while the ; beam
is bending in vertical direction (about X-X axis), it has also the' tendency to
buckle laterally (about Y-Y axis). Hence, before beam fails in bending, it may
fail by buckling in lateral direction. That is why in i actual calculation moment
capacity will be calculated by seeing perm. Stresses in bending compression
which will depend upon the unsupported length in lateral direction. They are
given in the table below.
I.
I