(1) In this Part, the term,
(a)“limit states” means those conditions of a building structure that result in the building ceasing to fulfill the function for which it was designed. (Those limit states concerning safety are called ultimate limit states (ULS) and include exceeding the load-carrying capacity, overturning, sliding and fracture; those limit states that restrict the intended use and occupancy of the building are called serviceability limit states (SLS) and include deflection, vibration, permanent deformation and local structural damage such as cracking; and those limit states that represent failure under repeated loading are called fatigue limit states),
(b)“specified loads (C, D, E, H, L, P, S, T and W)” mean those loads set out in Table 4.1.2.1.A.,
(c)“principal load” means the specified variable load or rare load that dominates in a given load combination,
(d)“companion load” means a specified variable load that accompanies the principal load in a given load combination,
(e)“service load” means a specified load used for the evaluation of a serviceability limit state,
(f)“principal-load factor” means a factor applied to the principal load in a load combination to account for the variability of the load and load pattern and the analysis of its effects,
(g)“companion-load factor” means a factor that, when applied to a companion load in the load combination, gives the probable magnitude of a companion load acting simultaneously with the factored principal load,
(h)“importance factor, I,” means a factor applied in Subsections 4.1.6. to 4.1.8. to obtain the specified load and take into account the consequences of failure as related to the limit state and the use and occupancy of the building,
(i )“factored load” means the product of a specified load and its principal-load factor or companion-load factor,
(j)“effects” refers to forces, moments, deformations or vibrations that occur in the structure,
(k)“nominal resistance, R,” of a member, connection or structure, is based on the geometry and on the specified properties of the structural materials,
(l)“resistance factor, Φ,” means a factor applied to a specified material property or to the resistance of a member, connection or structure, and that, for the limit state under consideration, takes into account the variability of dimensions and material properties, workmanship, type of failure and uncertainty in the prediction of resistance, and
(m)“factored resistance, ΦR,” means the product of nominal resistance and the applicable resistance factor.
(1) In proportioning structural members to limit serviceability problems resulting from deflections, consideration shall be given to,
(a) the intended use of the building or member,
(b) limiting damage to non-structural members made of materials whose physical properties are known at the time of design,
(c) limiting damage to the structure itself, and
(d) creep, shrinkage, temperature changes and prestress. (2) The lateral deflection of buildings due to service wind and gravity loads shall be checked to ensure that structural elements and non-structural elements, whose nature is known at the time the structural design is carried out, will not be damaged. (3) Except as provided in Sentence (4), the total drift per storey under service wind and gravity loads shall not exceed 1/500 of the storey height unless other drift limits are specified in the design standards referenced in Section 4.3. (4) The deflection limits required in Sentence (3) do not apply to industrial buildings or sheds if experience has proven that greater movement will have no significant adverse effects on the strength and function of the building. (5) The building structure shall be designed for lateral deflection due to E, in accordance with Article 4.1.8.13.