(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