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American Tunnel bu.Lkheads #2 & #3 Page z0 January 15, 2001 <br /> Appendix B. American Tunnel Bulkhead #3 design calculations (Continued) <br /> C = T; 30600a= 60000A8 2 a 60000A, _= 30600 1.961 AS <br /> co=U= 1.4p(144) = 1.4(335)144 =67,540(n� <br /> 6750122) = 1 216 <br /> a s >000 ft-lb <br /> M„ = 09 = 12og00 = 1,351,000 ft-lb (16,210,000 in-lb) <br /> M„=Asfy(d—z); d =L - m, = 11(12) - 3.5 = 128.5 in <br /> M„= 60000A,(d—2) = 60000AS(128.5— 1.921A,l = 771000OAs—58800A, <br /> Therefore: 16,210,000 = 7,710,000A,- 58,800AS <br /> 58,800AS- 7,710,000A, + 16,210,000 =0 <br /> A8= 2.137 ft steel area required for 11-ft thick bulkhead <br /> #10 bars (1.270 in' per bar) on 7-in c-c provides 2.177 s steel area <br /> Check for adequacy <br /> Allowable M„= -58,800AS + 7,710,000OAB= 16,510,000 in-lb <br /> Design Mu = 16,210,000 in.lb <br /> FS = 1610000 <br /> 16210000 <br /> = 1.02 for 11-ft thick bulkhead <br /> — <br /> Critical section shear strength for, American Tunnel Bulkhead #3 11-ft thick deep-beam <br /> bulkhead <br /> Deep beam defined as a < 5 (ACI 318-95, Sec 11.8.1). Critical section shear at 0.151 (1.90 <br /> ft) from ribside (ACI 318-95, Sec 11.8.5), with#10 bars on 7-in c-c, there will be 2.177 ft <br /> of steel per ft of beam width, d= 128.5 in(10.71 ft). <br /> Detailed shear strength at critical section(ACI 318-95, Sec 11.8.7) <br /> Q _ 1202> '44 = 1.12 < 5 Therefore reinforced concrete bulkhead <br /> d — [11(12�-3.51 — 128.5 <br /> is a deep beam for design! <br />