Steel Floor Deflection Limits

Clear span in inches l over a given number.

Steel floor deflection limits. Other than plaster or gypsum board. Clear span in inches l over a given number. Any non structural partition under the beam must be able to accommodate this deflection. For a bay in which mode b could not be assumed the span at which the limit of l 300 affects the design would be even less.

A floor joist appropriately selected to span 10 feet with an l 360 limit will deflect no more than 120 360 1 3 inches under maximum design loads. Plaster or gypsum board. Roof rafters roof joists and roof beams. For example the allowable deflection of a 12ft span floor joist with plaster l 360 is 0 4 12ft divided by 360.

Floor beams floor joists and floor. If that same joist had gypsum ceiling l 240 the allowable deflection is 0 6. B for cantilever members l shall be taken as twice the length of the cantilever. Other than plaster or gypsum board.

For aluminum structural members or panels used in roofs or walls of sunroom additions or patio covers not supporting edge of glass or sandwich panels the total load deflection shall not exceed l 60. A floor joist appropriately selected to span 10 feet with an l 360 limit will deflect no more than 120 360 1 3 inches under maximum design loads. A reliabihty index fi is defined as j8 g o g in which rug. These tolerances generally are expressed in terms as a maximum deflection value and must be considered in design.

For example a floor girder spanning 36 ft may deflect up to 1 2 inches under a live load only deflection limit of l 360. See the table below. For the purpose of the determining deflection limits herein. Maximum deflection limits are set by building codes.

They are expressed as a fraction. Horizontal deflection limits are given in table na2 examples of limiting values of horizontal deflections. Maximum deflection limits are set by building codes. Therefore a limit of l 300 would not have affected the design of this floor.

Allowable deflection as an expressed ratio of the clear span. The static deflection limit state for a uniformly loaded steel beam is g aa ktlei l 3 0 in which a is allowable deflection corresponding to some limit state l is uniform live load and a is a constant that depends on the end conditions and spacing of the beams.