Civil Engineering Reference
In-Depth Information
Section B (see Fig. 8.23):
V
E
= 3954
lb
V
D
3954
25
E
v
== =+
158 16
.
plf
E
VVwx
CE
=−=
3954
−
105 15
()
=
2379
lb unit shearat
grid lineC left
(
)
V
D
2379
25
C
v
== =+
95 16
.
plf
C
Chord forces for sections A and B:
wx
2
105 15
2
()
2
MV x
=− =
14 623 15
,
(
)
−
=
207,5
32.5 ft-lb
sect AE
2
M
207 532 5
25
,
.
sect A
F
=
=
=
8301 3
.
lb
sect A
D
wx
2
105 15
2
()
2
MV x
=− =
3954 15
()
−
=
47,498
ft-lb
sect B
E
2
M
47,498
sect B
F
=
=
=
1899 92
.
lb
sect B
25
D
Transfer diaphragms (see Fig. 8.24): Four transfer diaphragms have been created to
handle the disrupted chord forces, TD1 through TD4. The directions of the forces acting
on the transfer diaphragms are shown in the figure. All the transfer diaphragm aspect
ratios have been checked for loading in the transverse direction. Transfer diaphragm
TD2 has been added to resist the chord forces from sections A and B for loading in the
longitudinal direction. The ends of the transfer diaphragm are supported by shear walls
SW2 and SW3 and by the chord at grid line 9.
Transfer diaphragm TD2 aspect ratio:
70
35
TD
2
==,
2
unblocked herefore OK
,
Transfer diaphragm TD1 (see Fig. 8.24, upper right): Shear walls SW5 and SW6 are
assumed to act in the same line of lateral force resistance. The unit shears for shear walls
SW5 and SW6 must be determined before the force that is applied to transfer diaphragm
TD1 and its shears can be determined. The reactions of the diaphragm segments applied
to grid lines D and E and the total shear applied to shear wall SW6 are the total load
applied to the lateral-force-resisting wall line. Note that shear wall SW7 is isolated by
the notch and does not share the total shear force along that line. Its total force was
previously determined by the computer analysis.
Total shear to lines D and E:
∑
V
DE
=
2520
+
1575
+
2625
+
14 623
,
=
21 343
,
lb (Fig.
8821
.
)
−
∑
∑
V
L
21 343
60
,
DE
−
v
=
=
=
355 72
.
plfshear wal
llunitshear
SW
SW
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