Page 319 - Advanced Design Examples of Seismic Retrofit of Structures

308 Advanced Design Examples of Seismic Retrofit of Structures

5.7 ACCEPTANCE CRITERIA
Based on ASCE41-13 [3], for the linear and nonlinear procedure which has been
implemented in this example, component actions shall be compared with
capacities.

5.7.1 Linear Static Procedure
5.7.1.1 Deformation-Controlled Actions
Acceptance criteria for deformation-controlled actions in components shall sat-
isfy Eq. (5.27).
mκQ (5.27)
CE > Q UD
where:
m ¼component capacity modification factor to account for expected ductil-
ity associated with this action at the selected structural performance level. The
m-factors for use with corresponding expected strength shall be obtained from
Table 5.11;
Q CE ¼expected strength of component deformation-controlled action of an
element at the deformation level under consideration which is determined
according to Section 5.7; and
κ ¼knowledge factor defined in according to Table 2.12 which is assumed
to be 1.0 because the usual level of knowledge exists about the example build-
ings, including material properties, as-built sketches, etc.

Beams
The acceptance criteria of this section shall apply to flexural actions of struc-
tural steel elements that have a calculated axial load that does not exceed 10% of
the axial strength. Beam flexure and shear shall be considered deformation con-
trolled. Values for the m-factor used in Eq. (5.27) shall be as specified in
Table 5.11.

Columns
Based on ASCE 41 [3], for steel columns under combined axial compression
and bending stress, where the axial column load is less than 50% of the
lower-bound axial column strength, PCL, the column shall be considered defor-
mation controlled for flexural behavior and force controlled for compressive
behavior, and the combined strength shall be evaluated by Eq. (5.28) or Eq.
(5.29).
P UF
For 0:2 0:5
P CL

P UF 8 M x M y
+ + 1:0 (5.28)
P CL 9 m x M CEx m y M CEy