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Steel Designers Manual - TheBestFriend.org

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This material is copyright - all rights reserved. Reproduced under licence from The <strong>Steel</strong> Construction Institute on 12/2/2007<br />

To buy a hardcopy version of this document call 01344 872775 or go to http://shop.steelbiz.<strong>org</strong>/<br />

<strong>Steel</strong> <strong>Designers</strong>' <strong>Manual</strong> - 6th Edition (2003)<br />

468 Worked examples<br />

The<br />

<strong>Steel</strong> Construction<br />

Institute<br />

Silwood Park, Ascot, Berks SL5 7QN<br />

Subject<br />

BEAM EXAMPLE 3<br />

Chapter ref.<br />

UNIVERSAL BEAM<br />

SUPPORTING POINT LOADS<br />

16<br />

Design code Made by DAN Sheet no.<br />

BS 5950: Part 1 Checked by GWO<br />

For initial trial section select a UB with Mcx > 406 kNm.<br />

A 457 ¥ 152 ¥ 74 UB provides M cx of 429 kNm. Now check <strong>Steel</strong>work<br />

lateral-torsional buckling strength for segments AB, BC & CD. Design Guide<br />

Vol 1<br />

AB<br />

b = 0/406 = 0.0<br />

mLT = 0.57 Table 18<br />

M —<br />

= 0.57 ¥ 406 = 231.4 kNm<br />

For L E = 3.0 m, Mb = 288 kNm <strong>Steel</strong>work<br />

\ 288 > 231.4 kNm OK Design Guide<br />

Vol 1<br />

BC<br />

b = 377/406 = 0.93<br />

mLT = 0.97 Table 18<br />

M —<br />

= 0.97 ¥ 406 = 393.8 kNm<br />

But for LE = 3.0 m, Mb = 288 kNm Not OK<br />

Try 457 ¥ 191 ¥ 82 UB<br />

<strong>Steel</strong>work<br />

this provides Mb of 396 kNm > 393.8 kNm OK Design Guide<br />

Vol 1<br />

CD<br />

Satisfactory by inspection OK<br />

A 457 ¥ 191 ¥ 82 UB provides sufficient resistance to lateraltorsional<br />

buckling for each segment and thus for the beam as a<br />

whole.<br />

2

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