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Project Design Mogul Tunnel Bulkhead By JFA Date 8121/03 <br />10.6 x 9.5' 1 9' Thick. Station 2+411 <br />Sheet 4 of 6 <br />Reinforced concrete deer-beam bending stress design for eartbauake acceleration: <br />C = ~ ~ f ~ bW a = 0.85 (3000) 12 a = 30600 a <br />C= T 30600 a= 60000 A S <br />'I'=ASf y=60000 As <br />a = (60000 A x/30600 = 1.961 A s <br />Mn <br />Factored earthquake bending M n :_ - <br />moment, 0.9 <br />Minimum concrete rebar cover, d := 12•L t - m a <br />M a = 368655 <br />d = 104.5 in <br />M„=Aefy(d-a/2)=60000A9(d- 1.961 A~12)=60000ASd-58830A9z <br />58830 A s -60000 A s d+ M „* 12 = 0 C 1 := 58830 C 2 :_ -60000 •d <br />C 1 = 58830 C 2 = •-6270000 <br />2 <br />A ._-C2- C2 -4•C1•C3 A =0.71 in2 <br />s 2,C 1 s <br />ft-Ib <br />C3:=Mn•12 <br />C 3 =4423864 <br />One cage of#8 bars (0.79 in2 per bar, 1.000-in diameter) on 12-in c--c (11-in between bars) <br />provides 0.79 irn2/ft of steel area, <br />Therefore, A s := 0.79 in2 <br />Check for adequacy, <br />Allowable factored bending moment, A a :_ -C 1 • ~A slz - C 2 •A s A u = 4916584 <br />Design factored bending moment, M n•12 = 4423864 in-lb <br />A <br />Factor of safety, FS ;= a FS = 1.111 <br />M u•12 <br />in-Ib <br />