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 (9) Calculate weight of a single concrete unit using Table 27
(see Figure 68b).
W = [(16 x 12 - 2(4.25 x 9)] x 8 x 150/123
= 80.0 lb
Effective unit mass of the wall is,
me = KLM x
W
Area x g
= .72 x
80
(16 x 8) x 386.4
10002
= 1164.6 lb-ms2/in2
(10) From Equation (1),
TN = 2[pi](me/KE)1/2
= 2[pi](1164.6/36.19)1/2
= 35.6 ms
(11) Find support rotation using Figure 6-7 of NAVFAC P-397
and Figure 68a.
B/ru = 2.0/1.42
= 1.4
T/TN = 100.0/35.6
= 2.8
[therefore] Xm/XE = 16.5
Xm = 16.5 x .039
= .644 in
[theta] = tan -1(2Xm/L)
[theta] = tan -1(2 x .644/150)
=
49[deg] < .50[deg] O.K.
(12) Ultimate shear at db/2 from support,
Vu
= ru(L - db)/2
= 1.42 (150 - 10)/2
= 99.4 lb/in
Net area of the section from Table 27
An
= 2 x b x Face thickness/b
= 2 x 8 x 1.5/8
= 3.0 in2/in
2.08-252
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