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11/13/2007 13:57 FAX
<br />Project, Steve Adit Bulkhead, Sta. 2+65
<br />10' Thick. 10' Wide, 10' High, #6 Rebar
<br />References Used:
<br />4? 011/018
<br />By ME L/JFA Date 10/30/07
<br />Shoet I -of 8
<br />Calculations arc based on;
<br />Abel, J.F., Jr. Bulkhead d sign for acid mine drainaec: 1998, in Proc Western U.S. Mining-Impacted
<br />Watersheds, Joint Conf on Remediltion and Ecoloeicnl Risk Assessment 'l'echn Bogies, Denver, CO, 36 p
<br />American Concrete institute, 2002, BIIildin_Code reouirements for structural concrete (ACI 318-02) and
<br />commentary - ACI 318R-02: 369 p
<br />Wang, C.K. & C.G. Salmon, 1955, Reinforced concrete 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 (in2)
<br />bH, = beam width (ft)
<br />Bp = allowable breakdown pressure (psi)
<br />d = max distance, compressed concrete
<br />to center of tensile rebar (in)
<br />F-b,n = earthquake bulkhead load (1b)
<br />EI•,n = earthquake static fluid load (I b)
<br />f,:, = concrete tensile strength [3(f jl?':?
<br />f« = concrete shear strength [2(fc)1'21
<br />FS = factor of safety
<br />L = bulkhead (beam) thickness (ft)
<br />Ls = bulldiead shear thickness (A)
<br />I = moment of inertia (in4)
<br />K = [3.5 - 2.5(Mt,/d)]
<br />M = beam bending moment (ft-lb)
<br />Mt, = factored bending moment (ft-lb)
<br />Ma = nominal bending moment (ii- lb)
<br />Mua = earthquale bending moment (ft-lb)
<br />p = max hydraulic pressure head (psi)
<br />pW = ratio rebar to concrete areas = A,/(wbd)
<br />S = section modulus (in3)
<br />T = tensile bending unit force (lb/ft)
<br />U = factored Lmit strength required (I b/-ft)
<br />U't = earthquake unit strength required (lb/ft)
<br />V= concrete shear strength req u i re LI (I b/ft)
<br />Inputs:
<br />Beam width, b, ;= 1 ft (12 in)
<br />Bulkhead depth below surface, B,,, := 115
<br />Maximum bulkhead height, hb 10 ft
<br />Maximum bulkhead width, wb 10 ft
<br />Current tunnel height, ht 9 it
<br />Current tunnel width, wt 8.5 ft
<br />Design water head,, Z:= 120 ft
<br />Concrete compressive strength., f, := 3000
<br />ft
<br />psi
<br />ft
<br />Inbye line-of-sight water distance, Sts := 280
<br />Overburden rock &nsity, 7r - 163 pcf
<br />Concrete density, -i, := 151 pcf
<br />Water density, 7v,; := 62.4 pcf
<br />Minimum concrete rebar cover, m, := 3.5 in
<br />Rebar yield strength, fy := 60000 psi
<br />Pressure gradient with low-pressure
<br />concrete/rock contact grouting, pag •- 41 psi
<br />Gravity acceleration, &:= 32.2 fi/sec2
<br />Maximum earthquake acceleration, ot 0.239 g
<br />Bulkhead trial thickness, Lt := 10 ft
<br />Strength redaction factors
<br />Rebar flexure (tensile) strength, cps 0.90
<br />Reinforced concrete shear strength, 0.75
<br />Plain concrete flexure strength, Opc 0.55
<br />Reinforced concretc'flexure strengt' 0, := 0.90
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