L ATERAL S UPPORT S LIDE S HOW Modified for use in CE470, Purdue University, April 2004

Fully unsupported beams. The unbraced length is equal to the entire length of the member.

These beams are continually supported with the deck that is mechanically attached with screws or welds.

During construction, these girders are fully unsupported. The unbraced length is the full length of the girder. Once the joists are placed in position and attached, the unbraced length is reduced to the joist spacing.

Bracing is not only accomplished by joists. Here, beams are used as blocking and spaced to provide the necessary lateral support.

Similarly, for the Chemical Engineering Building addition (Purdue), the beams have no lateral support during placement of the metal deck. The girders, meanwhile, have an unbraced length corresponding to the spacing of the beams.

Another image of placement of metal deck for the Chemical Engineering addition.

The deck is attached to the beams with puddle welds. Shear studs are also welded in place so that the floor slab and beam will act as a composite section in flexure.

These beams are now fully laterally supported.

Lateral bracing must be used for any member loaded in bending, including those that are curved or inclined.