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L <br />Project Design Koehler Tunnel Bulkhead By JFA Date 7/21/03 <br />8.5' x 9' 112' Thick. Station 3+021 <br />Sheet 4 of 8 <br />Reinforced concrete deer-beam bending stress design for earthquake acceleration: <br />C = ~ ,~ f ~ bW a = 0.85 (3000) 12 a = 30600 a <br />C= T 30600 a= 60000 A e <br />Mn <br />Factored earthquake bending M u ;_ <br />moment, 0.9 <br />Mmimum concrete rebar cover, d := 12•L t - m ~ <br />T=A9f y=60000 A, <br />a = (60000 A x/30600 = 1.961 A a <br />M n = 725583 <br />ft-lb <br />d = 140.5 in <br />M„=A9fy(d-a/2)=60000A8(d-1.961A f2)=60000Aad-58830A92 <br />58830 A B -60000 A a d+ M ~* 12 = 0 C 1 := 58830 C 2 :_ -60000•d <br />C 1 = 58830 C 2 = -8430000 <br />As:= <br />-C2- C22-4'C1'C3 <br />2•C 1 <br />A s = 1.04 in2 <br />C3 := Mu•12 <br />C 3 = 8707000 <br />One cage of #10 bazs (1.27 inz per bar, 1.270-in diameter) on 14-in c-c (12.73-in between bars) <br />provides 1.089 inz/ft of steel azea. <br />Therefore, A s := 1.089 inz <br />Check for adequacy, <br />Allowable factored bending moment, A u ;_ -C 1 • ~A s`z - C 2•A s A u = 9110502 <br />Design factored bending moment, M u•12 = 8707000 in-lb <br />A <br />Factor of safety, FS := M 12 FS = 1.046 <br />u <br />in-lb <br />,a.em,.moa,an,sa, wx nn <br />