Page 265 - Advanced Design Examples of Seismic Retrofit of Structures

258 Advanced Design Examples of Seismic Retrofit of Structures

(A) (B)
FIG. 4.21 Beams and columns as two-end pin members under infill action. (A) Beams.
(B) Columns.
Because the beam-column connections in this example are simple, as an
alternative, the beams and columns of the building are checked as two-end
pin isolated beams with the infill action applied in l ceff and l beff from one end
for the columns and beams, respectively (see Fig. 4.21). The more precise
method to evaluate the adequacy of frame members involves modeling the
beams and columns and connection details. Based on considering the frame
members as two-end pin beams, the extreme flexural moments and shear forces
and the flexural and shear strengths of each member are calculated as:

Pl eff l l eff
M ¼ (4.41)
l

Pl l eff
V ¼ (4.42)
l
(4.43)
M CE ¼ ZF ye
V CE ¼ 1:5 0:4 A s F ye (4.44)
Because the shotcrete layers are applied on both sides of the infill wall, there
is no eccentricity from the frame in-plane symmetric axis, and hence no torsion
is activated on the frame sections.

Evaluation of the Walls in Out-of-Plane Direction
The infill walls should be able to tolerate the inertial forces acting in the out-of-
plane direction. The out-of-plane stiffness of the infill walls should be neglected
inmodeling.Therelationsand acceptancecriteriain thissectionare applicable to