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<br />Project, Pierce Adit Bulkhead Sta. 3+04
<br />12' Thick, 12' Wide, 12' Hieh #6 Rebar
<br />References Used.,
<br />4002/018
<br />By ME?;,11FA Date 10/30/07
<br />Sheet 1 of 8
<br />Calculations are based on:
<br />Abel, J.P., Jr. Bulkhea design for acid mine drainage: 1998, in Proc Wcstcrn U.S. Mining-Impacted
<br />Watersheds, Joint Confon Remedistion and Ecological Risk Assessment Technologies, Denver, CO, 36 p
<br />American Concrete Institute, 2002. building code rectuirementS f or structural cnn?;retc (ACT 318-07.) and
<br />commentary - AC1 318R-02: 369 p
<br />Wang, C.K. & C.G. Salmon, 1985, Reinforced concrete design: 4th ed., Harper & Rowe Publishers, inc.
<br />Notation:
<br />Inputs:
<br />a = minimum concrete compression zone
<br />depth (in) to balance rebar tension
<br />As = area of rebar (in)
<br />b,,, = beam width (ft)
<br />BP = allowable breakdown pressure (psi)
<br />d = max distance, compressed concrete
<br />to center of tensile rebar (in)
<br />Ebm = earthquake bulkhead load (lb)
<br />Et;n = earthquake static fluid load (lb)
<br />fl = concrete tensile strength [3(f,)112]
<br />fC4 = concrete shear strength [2(fe)1`2]
<br />FS = factor of safety
<br />L = bulkhead (beam) thickness (ft)
<br />Ls = bulkhead shear thickness (ft)
<br />I = moment of inertia (in°)
<br />K = [3.5 - 2.5(M,/d)]
<br />M = beam bending moment (ft-lb)
<br />Mu = factored bending moment (ft-lb)
<br />Mn = nominal bending moment (R-lb)
<br />Mua = earthquake bending moment 01-1b)
<br />p = max hydraulic pressure head (psi)
<br />p, = ratio rebar to concrete areas = A,/(wbd)
<br />S = section modulus (in3)
<br />T = tensile bending unit force (lb/ft)
<br />U = factored unit strength required (lb/ft)
<br />Ua = earthquake unit strength required (lb/ft)
<br />V = concrete shear strength requin-d (lb/ft)
<br />Beam width, bµ, := 1 ft (12 in)
<br />Bulkhead depth below surface, B,,,.= 125 ft
<br />Maximum bulkhead height, hb 12 ft
<br />Maximum bulkhead width, wb 12 ft
<br />Current tunnel heig,11t, ht := 11 ft
<br />Current tunnel width, wt := 11 ft
<br />Design water head, a:= 120 ft
<br />Concrete compressive strength, fe- := 3000 psi
<br />Inbye line-of-sight )?,rater distance, SIS 313 ft
<br />Overburden rock density, -l, := 163 pcf
<br />Concrete density, ^jc := 151 pcf
<br />Water density, ' w := 62.4 pcf
<br />Minimum concrete rebar cover, me := 3.5 in
<br />Rebar yield strength, fy := 60000 psi
<br />Pressure gradient with lore-pressure
<br />concrete/rock contact grouting, Pag __ 41 psi
<br />Gravity acceleration, &:= 32.2 ft/sec2
<br />Maximum earthqua12%e acceleration, ot := 0.239.g
<br />Bulkhead trial thickness, Lt := 12 ft
<br />Stren th reduction factors
<br />Rebar flexure (tensile) strength, (Nrt 0.90
<br />Reinforced concrete shear strength, O,s 0.75
<br />Plain concrete flexure strength, Opc 0.55
<br />Reinforced concrete flexure strengtLOfe := 0.90
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