Draft

Chapter 10

BRACED ROLLED STEEL BEAMS

1 Thischapterdealswiththebehavioranddesignoflaterallysupportedsteelbeamsaccord-

ingto theLRFDprovisions.

2 A laterallystablebeamis onewhich is bracedlaterallyin thedirectionperpendicularto the

planeof theweb. Thusoverallbucklingof thecompression
angeas a columncannotoccur

priorto itsfullparticipationto developthemoment strengthof thesection.

3 If a beamis notlaterallysupported,Fig.10.1, we willhave a failuremode governedby lateral

A) COMPOSITE BEAM B) OTHER FRAMING

C) CROSS BRACING

Figure10.1:LateralBracingforSteelBeams

torsionalbuckling.

4 Bytheendof thislectureyoushouldbe ableto selectthemostecient section(light weight

withadequatestrength)fora given bendingmoment andalsobe ableto determinethe
exural

strengthof a givenbeam.