Page 84 - Advanced Design Examples of Seismic Retrofit of Structures

76 Advanced Design Examples of Seismic Retrofit of Structures

The values of V r of the walls in the example building walls are presented in
Appendix Table A-C-2-10. As an example, the rocking capacity of Wall#1 on
the first row of this table is determined as:
0:93
V r 1 ¼ 0:91 10883 + 0:5 2864ð Þ ¼ 5726kg
1:8

Expected In-Plane Bed-Joint Sliding Strength of URM Walls and Piers
Based on ACE41-13 [2], the expected initial lateral strength, Q CE , of URM
walls or pier components for bed-joint sliding failure mode shall be calculated
in accordance with Eq. (2.32):
(2.32)
Q CE ¼ V bjs1 ¼ v me A n
where:
A n ¼area of net mortared or grouted section of a wall or wall pier;
v me ¼expected bed-joint sliding shear strength in accordance with Eq.
(2.33); and
V bjs1 ¼expected initial shear strength of wall or pier based on bed-joint
sliding shear strength.

P D
0:75 0:75v te +
A n
v me ¼ (2.33)
1:5
where:
v te ¼mean of the bed-joint shear strength test values; and
P D ¼superimposed dead load at top of the wall or pier under consideration.
Values for the lower-bound bed-joint shear strength test value, v tL , shall not
exceed 0.69MPa for the determination of v mL in Eq. (2.33). The 0.75 factor on
v tL shall not be applied for single-wythe masonry walls.
Expected final lateral strength, Q CE, F , of URM walls or pier components
shall be calculated in accordance with Eq. (2.34):
Q CE,F ¼ V bjs2 ¼ 0:5P D (2.34)
where:
P D ¼superimposed dead load at top of the wall or pier under consideration;
and
V bjs2 ¼expected final shear strength of wall or pier based on bed-joint slid-
ing shear strength.
Code 360 [10] considers the expected lateral strength of URM walls or pier
components without distinguishing between the initial and final lateral
strengths. This approach is accordance to the previous version of ASCE 41, that
is, ASCE 41-06 [15].