This chapter shall apply to selection of load factors and combinations used in design, except as permitted in Chapter 27.
Loads and Seismic Design Categories (SDCs) shall be in accordance with the general building code, or determined by the authority having jurisdiction.
Required strength U shall be at least equal to the effects of factored loads in Table 5.3.1, with exceptions and additions in 5.3.3 through 5.3.12.
Table 5.3.1—Load combinations
|Load combination||Equation||Primary load|
|U = 1.4D||(5.3.1a)||D|
|U = 1.2D + 1.6L + 0.5(Lr or S or R)||(5.3.1b)||L|
|U = 1.2D + 1.6(Lr or S or R) + (1.0L or 0.5W)||(5.3.1c)||Lr or S or R|
|U = 1.2D + 1.0W + 1.0L + 0.5(Lr or S or R)||(5.3.1d)||W|
|U = 1.2D + 1.0E + 1.0L + 0.2S||(5.3.1e)||E|
|U = 0.9D + 1.0W||(5.3.1f)||W|
|U = 0.9D + 1.0E||(5.3.1g)||E|
If applicable, L shall include (a) through (f):
(a) Concentrated live loads
(b) Vehicular loads
(c) Crane loads
(d) Loads on hand rails, guardrails, and vehicular barrier systems
(e) Impact effects
(f) Vibration effects
The structural effects of forces due to restraint of volume change and differential settlement T shall be considered in combination with other loads if the effects of T can adversely affect structural safety or performance. The load factor for T shall be established considering the uncertainty associated with the likely magnitude of T, the probability that the maximum effect of T will occur simultaneously with other applied loads, and the potential adverse consequences if the effect of T is greater than assumed. The load factor on T shall not have a value less than 1.0.
If fluid load F is present, it shall be included in the load combination equations of 5.3.1 in accordance with (a), (b), (c) or (d):
(a) If F acts alone or adds to the effects of D, it shall be included with a load factor of 1.4 in Eq. (5.3.1a).
(b) If F adds to the primary load, it shall be included with a load factor of 1.2 in Eq. (5.3.1b) through (5.3.1e).
(c) If the effect of F is permanent and counteracts the primary load, it shall be included with a load factor of 0.9 in Eq. (5.3.1g).
If lateral earth pressure H is present, it shall be included in the load combination equations of 5.3.1 in accordance with (a), (b), or (c):
(a) If H acts alone or adds to the primary load effect, it shall be included with a load factor of 1.6.
(b) If the effect of H is permanent and counteracts the primary load effect, it shall be included with a load factor of 0.9.
(c) If the effect of H is not permanent but, when present, counteracts the primary load effect, H shall not be included.
Required strength U shall include internal load effects due to reactions induced by prestressing with a load factor of 1.0.
For post-tensioned anchorage zone design, a load factor of 1.2 shall be applied to the maximum prestressing reinforcement jacking force.