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Gold Prince Portal Bulkhead Calcs Page 3 August 19, 1996 <br /> bL3 l(L3)(123) <br /> I _ 12 _ 12 _ 144L3 <br /> $ = c— L— t12> — 6 <br /> 2 2 <br /> fc1 = 3 Ff7c = 3 3000 = 164psi <br /> Muc _ Mu __ 23700 = 988 <br /> fc1 = 164= = I S 144L2 L2 <br /> 6 <br /> L= 124 = 6.04 =2.45 ft Therefore, 2.5-ft long bulkhead needs no <br /> reinforcement. <br /> = Mu = Mu _ 23700 = 23700 = 158 Sl <br /> S 144112 144(2.52) 150 P <br /> 6 <br /> 6 <br /> FS = 1 fQ = 164 = 1.04 <br /> 158 <br /> Critical section shear strength for Prince Mine Tunnel, 5-ft deep beam bulkhead) <br /> Deep beam defined as 1 < 5 (ACI 318-89, Sec I I.8.1). Critical section shear at 0.151 (1.28 <br /> ft) from ribside(ACI 318-89, Sec 11.8.5), with reinforcing bars, there will be no reinforcing <br /> steel in the beam. <br /> Detailed shear strength at critical section(ACI 318-89, Sec 11.8.7) <br /> 1 = 10.5(12) _ 126 =4.20 <5 Therefore, plain concrete bulkhead is a deep beam for design! <br /> d [2.5(12)] 30 <br /> V. =K(1.9 f� +2500p,,,Md)bw,d <br /> 1VIa= (2)(0.151)—w(0.15 1)°'2 1 =0.06375 22 = 0.06375[12302102)] =3921 ft lb <br /> _ M° __ 3921 =4356 ft-lb <br /> 0.9 0.9 <br /> V. — 21 —(21)(o s 11) =0.35w1 =0.35(1230)10=43051b <br /> V. = vn = 4305 = 5065 lb <br /> 0.85 0.85 <br /> K= 3.5 -2.5 M° =3.5 - 2.5 4365 =3.5 - 0.86=2.64 <br /> Vud 5065(30) <br /> 12 <br /> K cannot exceed 2.5 Therefore K=2.5 <br /> 3 <br />