Page 87 - Advanced Design Examples of Seismic Retrofit of Structures

Example of a Two-Story Unreinforced Masonry Building Chapter 2 79

where:
f m ¼lower-bound compressive strength; and
0
A n ¼area of net mortared and/or grouted section.
The values of P CL of the walls in the example building walls are presented in
Appendix Table A-C-2-10. As an example, the vertical compressive capacity of
Wall#1 on the first row of this table is determined as:
P CL ¼ 0:80 0:85 30 3255ð Þ ¼ 66;402 kg

2.7.6 Acceptance Criteria

Based on ASCE 41-13 [2], in-plane lateral shear of URM walls and piers in each
line of resistance shall be considered a deformation-controlled action if the
expected lateral rocking strength or bed-joint sliding strength of each wall or
wall pier in the line of resistance, as specified in “Expected In-Plane Rocking
Strength of URM Walls and Piers” and “Expected In-Plane Bed-Joint Sliding
Strength of URM Walls and Piers” sections, respectively, is less than the lower-
bound lateral strength of each wall or pier limited by toe crushing or diagonal
tension, as specified in “Lower-Bound In-Plane Toe-Crushing Strength of URM
Walls and Piers” and “Lower-Bound In-Plane Diagonal Tension Strength of
URM Walls and Piers” sections, respectively. The expected rocking strength,
V r , as specified in “Expected In-Plane Rocking Strength of URM Walls and
Piers” section, shall be neglected in lines of resistance not considered deforma-
tion controlled.
For the linear procedure which has been implemented in this example, com-
ponent actions shall be compared with capacities in accordance with Sections
2.7.6.1 and 2.7.6.2. When in-plane URM wall response is governed by bed-joint
sliding, V bjs1 shall be used when assessing component behavior at the immedi-
ate occupancy performance level and V bjs2 shall be used for all other perfor-
mance levels.

2.7.6.1 Deformation-Controlled Actions
Acceptance criteria for deformation-controlled actions in components shall sat-
isfy Eq. (2.38):
mκQ CE > Q UD (2.38)
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 2.11;