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Ransom Tunnel Bulkhead Page 6 May 7, 1997 <br /> M„= 60000A,(d—2) = 60000A8(92.5— 1'""') = 5550000As—58800A2 <br /> Therefore: 9,233,000=5,550,000AB- 58,000AS <br /> 58,800AS- 5,550,000A6+ 9,233,000 = 0 <br /> As= 1.69 ft steel area required <br /> #10 bars on 8-in c-c provides 1.905 `ft steel area <br /> Check for adequacy <br /> Allowable M.= -58,800A2 + 5,550,0000A, = 10,360,000 in-lb <br /> Design Mu =9,233,000 in-lb <br /> 10360000 = <br /> FS = 9233000 1.12 <br /> Critical section shear strength for Ransom tunnel, 8-ft deep beam bulkhead <br /> Deep beam defined as a < 5 (ACI 318-95, Sec 11.8.1). Critical section shear at 0.151 (1.28 <br /> ft) from ribside (ACI 318-95, Sec 11.8.5), with#10 bars on 8-in c-c, there will be 1.905 a <br /> of steel per ft of beam width, d = 92.5 in(24.71 ft). <br /> Detailed shear strength at critical section(ACI 318-95, Sec 11.8.7) <br /> d — 1002) 1�° <br /> d — [8(12)-3.5] — 92.5 = 1.30 < 2 Therefore, reinforced concrete bulkhead is a <br /> deep beam for design! <br /> v„- nominal shear stress shall not be greater than 8 f when d < 2 <br /> (ACI 318-95, Sec 11.8.4) <br /> Limiting value: v„ <8 3000 < 438 psi V„<(v0b,,,d<—(438)12(92.5)< 486,200 lb <br /> V.= ' -(z�)r os) = 0.35a)l = 0.35(55400)10 = 193,900 lb <br /> VU v„ _ 193900 = <br /> 0.85 — 0.85 228 100 lb <br /> K,= (2')(0.15 1)—co(0.15 1)0.15 = 0.06375 22 = 0.06375[55402(102)] <br /> M„= 176,100 ft-lb <br /> = 6 = 176100 = 196,200 ft-lb <br /> .9 0.9 � <br /> 6 <br />