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Project Design Mogul Tunnel Bulkhead <br />10.6 x 9.5' (9' Thick. Station 2+411 <br />By JFA Date 8/21/03 <br />Sheet 4 of 6 <br />Reinforced concrete deerrbeam bending stress design for earthquake acceleration: <br />C=~~f~bwa =0.85(3000) 12a=30600a <br />C= T 30600 a= 60000 A S <br />T=Asf y=60000 As <br />a = (60000 A x/30600 = 1.961 A s <br />Mn <br />Factored earthquake bending M u :_ <br />moment, 0.9 <br />Minimum concrete rebaz cover, d := 12•L t - m e <br />M u = 368655 <br />d = 104.5 in <br />M~=Agfy(d-a/2)=60000As(d- 1.961 A~12)=60000Asd-58830Asz <br />58830 A sz -60000 A g d+ M „* 12 = 0 C 1 := 58830 C 2 :_ -60000•d <br />C 1 = 58830 C 2 = -6270000 <br />z <br />A ._-C2- C2 -4•C1•C3 A =0.71 inz <br />s 2,C 1 s <br />ft-lb <br />Cg:=Mu•12 <br />C 3 = 4423864 <br />One cage of #8 bazs (0.79 inz per bar, 1.000-in diameter) on 12-in c-c (11-in between bars) <br />provides 0.79 inz/ft of steel azea. <br />Therefore, A s := 0.79 inz <br />Check for adequacy, <br />Allowable factored bending moment, A u :_ -C 1 • ~A slz - C 2•A s A u = 4916584 <br />Design factored bending moment, M u • 12 = 4423864 in-Ib <br />A <br />Factor of safety, FS := u FS = I.1 I1 <br />M u•12 <br />in-Ib <br />e+~ta~s ~e aav~sm vn,ut <br />