2008-04-21_REVISION - M1977300 (2)

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S .f r u c`}-ur~~ Project, Steve Adit Bulkhead, As-Built Sta. 2+65 10' Thick, 7'-7" Wide, 8'-2" High, #6 Rebar References Used: ~~~~~~~~id~s By MEL/JFA Date 3/28/08 Sheet 1 of 8 Calculations are based on: Abel, J.F., Jr. Bulkhead design for acid mine drainage: 1998, in Proc Western U.S. Mining-Impacted Watersheds, Joint Conf on Remediation and Ecological Risk Assessment Technologies, Denver, CO, 36 p American Concrete Institute, 2002, Building code requirements for structural concrete (ACI 318-02) and commentary -ACI 3l 8R-02: 369 p Wang, C.K. & C.G. Salmon, 1985, Reinforced concrete design: 4th ed., Harper & Rowe Publishers, Inc. Notation: • a =minimum concrete compression zone depth (in) to balance rebar tension AS =area of rebar (in2) bw =beam width (ft) Bp =allowable breakdown pressure (psi) d = max distance, compressed concrete to center of tensile rebar (in) Ebm =earthquake bulkhead load (lb) Efm =earthquake static fluid load (lb) fc1=concrete tensile strength [3(f~Ii2] fps =concrete shear strength [2(f~)I~2] FS =factor of safety L =bulkhead (beam) thickness (ft) Ls =bulkhead shear thickness (ft) I =moment of inertia (in4) M =beam bending moment (ft-lb) M„ =factored bending moment (ft-lb) Mn =nominal bending moment (ft-lb) M„a =earthquake bending moment (ft-lb) p = max hydraulic pressure head (psi) pW =ratio rebar to concrete areas = AS/(wbd) S =section modulus (in3) T =tensile bending unit force (lb/ft) U =factored unit strength required (lb/ft) Ua =earthquake unit strength required (lb/ft) V =concrete shear strength required (lb/ft) Inputs: Beam width, bw := 1 ft (12 in) Bulkhead depth below surface, Bw := 115 ft Maximum bulkhead height, hb := 8.167 ft Maximum bulkhead width, wb := 7.59 ft Current tunnel height, ht := 8.167 ft Current tunnel width, wt := 7.59 ft Design water head, H := 120 ft Concrete compressive strength, f~ := 6390 psi Inbye line-of--sight water distance, Sls := 280 ft Overburden rock density, 'Yr := 163 pcf Concrete density, 7c := 151 pcf Water density, ~y,,, := 62.4 pcf Minimum concrete rebar cover, m~ := 3.5 in Rebar yield strength, fy := 60000 psi Pressure gradient with low-pressure concrete/rock contact grouting, pag '- 41 psi Gravity acceleration, ~:= 32.2 ft/sec2 Maximum earthquake acceleration, o~ := 0.239•g Bulkhead trial thickness, Lt := 10 ft Strength reduction factors Rebar flexure (tensile) strength, art := 0.90 Reinforced concrete shear strength, ors := 0.75 Plain concrete flexure strength, ~pc := 0.55 Reinforced concrete flexure strengt arc := 0.90