Page 235 - Advanced Design Examples of Seismic Retrofit of Structures

228 Advanced Design Examples of Seismic Retrofit of Structures

TABLE 4.10 Expected Shear Strengths of Infill Panels—cont’d
Story Axis h inf (cm) L inf (cm) t inf (cm) θ (degree) Q CE (kg)
2nd C-1-3 280 540 20 27.41 11,008
2nd C-4-5 280 540 20 27.41 11,008
2nd F-1-3 280 540 20 27.41 11,008
2nd F-4-5 280 540 20 27.41 11,008
2nd G-1-3 280 540 20 27.41 11,008
2nd G-4-5 280 540 20 27.41 11,008
2nd H-1-3 280 540 20 27.41 11,008
2nd H-4-5 280 540 20 27.41 11,008

Building’s Base Shear
Based on the LSP, the seismic demand force is calculated based on Section 3-3-
3-2 of the Iranian Code of Retrofitting of Existing Structures (Code 360) [10] as
follows:

V ¼ C 1 C 2 C m S a W (4.17)

where:
V ¼pseudo lateral force; and
S a ¼response spectrum acceleration, at the fundamental period and damping
ratio of the building in the direction under consideration which is determined
based on Section 1-7 of Code 360 [10]. The example building is located
on soil type III in a region with very high seismicity. As a result, and based
on the natural period of the building determined in Section “Natural
Period of the Building,” S a is the maximum spectral acceleration
2.75 0.35g¼0.9625g (see Fig. 4.14);
W¼effective seismic weight of the building, including the total dead load
and applicable codified portions of other gravity loads. According to Code
360, the dead loads also include the weight of partition walls and the total
operating weight of permanent equipment, and the live loads are 20% of the
codified live loads including snow [10]; and
C 1 ¼modification factor to relate expected maximum inelastic displace-
ments to displacements calculated for linear elastic response. This factor
is determined based on either of these methods.