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B- Level/Brenneman Bull d Design <br />Reinforced concrete beam bending stress design, B- Level/Brenneman Bulkheads (ACI 318R -92, <br />Sec 9.3.2.1, Sec 10.5.1, Sec 11.8. Wang & Salmon, 1985, Einarson & Abel, 1990) <br />C = Or, , b„,a = 0.85(2500)12a = 25500a <br />T = A,f = 60000A, <br />60000A, <br />C = T ; a = — 2.353A, <br />25500 <br />w� 6050(9 <br />M. = 8 — 8 — 61300 ft • lb <br />Mu — M = 613 00 — 68100 ft lb (817000 in • lb) <br />0 <br />M = A,f d - aJ ; d = L - m = 3(12) - 3.5 = 32.5 in <br />M = 60000A - = 60000A,(32.5 - 35 3A,) = -7060A, + 1950000A, <br />817000 = -7060A + 1950000A, <br />7060A, - 1950000A, + 817000 = 0 <br />A = 0.42 in 2 steel area required to support bending <br />in2 � 13 <br />#6 bars on 9 -in c -c provide 0.59 ft steel area 64AA <br />Check for adequacy <br />Allowable M = - 7060A; + 1950000A, = 1170000 in • lb <br />Design M = 817000 in lb <br />FS = 1170000 — 1.43 <br />817000 <br />Deep beam defined as e >— 5 (ACI 318R -92, Sec 10.7.1). <br />Page 4 February 21, 1994 <br />L _ 3 <br />7 9 = 0.33 3 -ft thick (e) bulkhead in 9 -ft wide tunnel (L) is NOT a deep beam <br />and bulkhead design must meet either the requirement for "ratio of nonprestressed tension <br />reinforcement" p — b d (ACI 318R -92, Sec 10.5.1) or (ACI 318R -92, Sec 10.5.2). <br />W <br />