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11/13/2007 13:56 FAX
<br />Project, Pierce Adit Bulkhead Sta. 3+04
<br />12' Thick,_12' Wide, 12' High, #6 Rebar
<br />References Used:
<br />? 002/n 18
<br />By MEL/dFA Date 10/30/07
<br />Sheet 1 of 8
<br />Calculations are based on:
<br />Abel, J.P., Jr. Bulkhead design for acid mine drainage: 1998, in Proc ?Vestcrn U.S. dining Impacted
<br />Watersheds, Joint Conf on Remediation and Ecological Risk Assessment Technologies, Denver, CO, 36 p
<br />American Concrete Institute, 2002. Diiildinrz code requirements for structural conrretc (ACT 318-42) and
<br />commentary - ACI 318R-02: 369 p
<br />Wang, C.K. & C.G. Salmon, 1985, Reinforced goncrcte design: 4th ed„ Harper & Rowe Publishers, Inc.
<br />Notation:
<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 />El;n = earthquake static fluid load (lb)
<br />fcl = concrete tensile strength [3(f,)112]
<br />fps = concrete shear strength [2(fc)1'2]
<br />FS = factor of safety
<br />L = bulkhead (beam) thickness (ft)
<br />Ls = bulkhead shear thickness (ft)
<br />I = moment of inertia (in4)
<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 (ft-lb)
<br />p = max hydraulic pressure head (psi)
<br />P,v = 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 required (lb/ft)
<br />Inputs:
<br />Beam width, b,,, := 1 ft (12 in)
<br />Bulkhead depth below surface, Bw := 125
<br />Maximum bulkhead height, hb 12 ft
<br />Maximum bulkhead width, wb 12 ft
<br />Current tunnel heig,lit, ht := 1 l ft
<br />Current tunnel width, wt := 11 ft
<br />Design water head, lu:= 120 ft
<br />Concrete compressive strength, fc := 3000
<br />Inbye line-of-sight water distance, Sls := 313
<br />Overburden rock density, 1,:= 163 P
<br />Concrete density, -ic := 151 pcf
<br />Water density, 1, := 62.4 pcf
<br />Minimum concrete rebar cover, me := 3.5
<br />Rebar yield strength, fy := 60000 psi
<br />Pressure gradient with IwN,-pressure _
<br />concrete/rock conitact grouting, Pag 41
<br />Gravity acceleration., 32.2 ft/sec2
<br />Maximum earthqual.:e acceleration, ot := 0.,'
<br />Bulkhead trial thickness, Lt := 12 ft
<br />Stren th reduction factors
<br />ft
<br />I
<br />psi
<br />ft
<br />cf
<br />in l
<br />psi
<br />39-g
<br />Rebar flexure (tens] le) strength, (,rt 0.90
<br />Reinforced concrete shear strength, airs 0.75
<br />Plain concrete flexure strength, opc 0.55
<br />Reinforced concrete flexure strengtL C?rc := 0.90
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