In AP analysis with any of the three methods (Linear Static, Nonlinear Static,

and Nonlinear Dynamic), the designer must quantify the extent of damage during the

analysis and at the end of the analysis.

For the removal of a wall or column on the external envelope of a building t,

the Damage Limits require that the collapsed area of the floor directly above the

removed element must be less than the smaller of 70 m2 (750 ft2) or 15% of the total

area of that floor and the floor directly beneath the removed element should not fail. In

addition, any collapse must not extend beyond the structure tributary to the removed

element.

For the removal of an internal wall or column of a building, the Damage Limits

require that the collapsed area of the floor directly above the removed element must be

less than the smaller of 140 m2 (1500 ft2) or 30% of the total area of that floor, and the

floor directly beneath the removed element should not fail. In addition, any collapse

must not extend beyond the bays immediately adjacent to the removed element.

The Acceptability Criteria for the AP method consist of strength requirements

and deformation limits. The moments, axial forces, and shears that are calculated for

the elements and connections in each AP analysis are the Required Strengths, as

defined in Equation 3-2. These Required Strengths must be compared to the Design

Strengths of each element and connection, as shown generically in Table 3-1. In

addition, the deflection and rotations that are calculated in the AP model must be

compared against the deformation limits that are specific to each material type. If any

structural element or connection violates an acceptability criteria (strength or

deformation), modifications must be made to the model before it is re-analyzed, as

indicated in Table 3-1 and discussed in more detail in the following sub-sections.

The acceptability criteria for flexural loads is based on the flexural design

strength of the structural element, including the strength reduction factor Φ, and the

over-strength factor Ω applied to the material properties as appropriate. In calculating

the flexural design strength, account for the material-specific factors that can reduce the

flexural design strength, such as compactness and lateral bracing for structural steel,

amount of rebar in reinforced concrete, etc.

When the internal moment (flexural required strength) determined by the AP

model exceeds the flexural design strength of an element, the element is either

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