4.1.5.8. Variation With Tributary Area

(See Note A-4.1.5.8.)

(1)

One- and two-way floor slabs shall have no reduction for tributary area applied to live load.

(2)

An area used for assembly occupancies designed for a live load of less than 4.8 kPa and roofs designed for the minimum loading specified in Table 4.1.5.3. shall have no reduction for tributary area.

(3)

Where a structural member supports a tributary area of a floor or a roof, or a combination thereof, that is greater than 80 m2 and either used for assembly occupancies designed for a live load of 4.8 kPa or more, or used for storage, manufacturing, retail stores, garages or as a footbridge, the specified live load due to use and occupancy is the load specified in Article 4.1.5.3. multiplied by where A is the tributary area in square metres for this type of use and occupancy.

(4)

Where a structural member supports a tributary area of a floor or a roof, or a combination thereof, that is greater than 20 m2 and used for any use or occupancy other than those indicated in Sentences (2) and (3), the specified live load due to use and occupancy is the load specified in Article 4.1.5.3. multiplied by where B is the tributary area in square metres for this type of use and occupancy.

(5)

Where the specified live load for a floor is reduced in accordance with Sentence (3) or (4), the structural drawings shall indicate that a live load reduction factor for tributary area has been applied and which structural elements are impacted by this factor.