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American Tunnel bulkheads #2 & #3 Page 21 January 15, 2001 <br /> Appendix B. American Tunnel Bulkhead #3 design calculations (Continued) <br /> vn- nominal shear stress shall not be greater than 8 ire when e < 2 <br /> (ACI 318-95, Sec 11.8.4) <br /> Limiting value: vn <8 3000 <438 psi Vn<(vOb,Vd<(438)12(128.5) <678,400 lb <br /> Vn= �i-(ii)(o")=0.35coQ = 0.35(67840)12 = 284,900 lb <br /> V. __ 2841 = 335,200 lb <br /> V. <br /> 0.85 0.85 <br /> Mn= (`Z)(0.15 Q)—co(0.15 0)O.�SQ = 0.06375 2 = 0.0637516780,,2>] <br /> Mn= 311,400 ft-lb <br /> 1�, = vv = 31" = 346,000 ft•lb <br /> 0. 0.9 <br /> V� =K(1.9 f� +2500pW"a)b,Vd <br /> K= 3.5 - 2.5mu = 3.5 - 2.5[ 34600°�3 , = 3.5 - 0.24 = 3.26 <br /> 335200(12 ) <br /> K cannot exceed 2.5 Therefore K= 2.5 <br /> pW — , — (12)128.5 = 0.001412 Trial, #10 bars on 7-in centers, two-way <br /> V,=K(1.9 f, +2500pw Md)bwd <br /> 335200(122S5) 1 <br /> V,=2.5 1.9 3000 +2500(0.001817) 346" J 12(128.5) <br /> V,=2.5[104.1 +47.1]1542 =2.5[151.2]1542 = 582,900 lb <br /> Allowable Vc<(6 f.)bWd—<(6 3000 )12(128.5) = 506,8001b (ACI 318-95, Sec 11.8.7) <br /> Therefore FS= v` = 506800 = 1.51 <br /> vu 335200 <br /> Earthquake bulkhead design; Load factors(ACI 318-95, Sec 9.2.2, 9.2.3, 9.2.5): Factor for fluid <br /> load under earthquake acceleration(F) = 1.05; Load factor for earthquake accelerated mass <br /> (E) = 1.40. Maximum credible earthquake acceleration(a) is 0.0872 . <br /> Sm <br /> U= 1.05F+ 1.40E <br />