UFC 4-023-03
25 January 2005
3-2.4.2
Linear and Nonlinear Static Analysis Load Case.
For Linear and Nonlinear Static analyses of all construction types, apply the
following amplified factored load combination to those bays immediately adjacent to the
removed element and at all floors above the removed element; see Figures 3-7 and 3-8.
2.0 [ (0.9 or 1.2) D + (0.5 L or 0.2 S) ] + 0.2 W
For the rest of the structure, apply the load combination in Section 3-2.4.1.
For load-bearing wall systems, the adjacent bay is defined as the plan area
that spans between the removed wall and the nearest load-bearing walls.
3-2.4.3
Loads Associated with Failed Elements.
As discussed later, the internal forces or deformation in a structural element
or connection may be shown to exceed the acceptability criteria. If so, the element is
considered to be failed and is removed from the model.
For a Nonlinear Dynamic analysis, double the loads from the failed element to
account for impact and apply them instantaneously to the section of the structure
directly below the failed element, before the analysis continues. Apply the loads from
the area supported by the failed element to an area equal to or smaller than the area
from which they originated.
For a Linear or Nonlinear Static analysis, if the loads on the failed element are
already doubled as shown in Section 3-2.4.2, then the loads from the failed element are
applied to the section of the structure directly below the failed element, before the
analysis is re-run or continued. If the loads on the failed element are not doubled, then
double them and apply them to the section of the structure directly below the failed
element, before the analysis is re-run or continued. In both cases, apply the loads from
the area supported by the failed element to an area equal to or smaller than the area
from which they originated.
3-2.5
Material Properties.
Material properties, such as yield stress, failure stress, etc, must be taken in
accordance with the requirements of the appropriate material specific code. For some
construction types, an over-strength factor Ω or time effect factor λ is permitted, to
account for the typical over-strengths expected for that material. The appropriate
factors to increase the nominal strength for each material are given in Chapters 4
through 8.
3-11
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