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<br />Project As Built Koehler Tunnel Bulkhead <br />8.42' x 10.5' (12.04' Thick, Sta 3+02) <br />Notation continued: <br />V „=nominal concrete shear strength (Ib/ft) <br />V „ =factored concrete shear strength (lb/ft) <br />vs = rebar shear stress (psi) <br />W =total bulkhead load (Ib) <br />Z =height of rack to prevent hydrofrac (ft) <br />4 orb =Overburden rock stress per ft of depth (psi) <br />~ rs =factored static fluid bulkhead load (psf) <br />or rye =factored static fluid bulkhead earthquake <br />load (psf) <br />~ ne =factored line of sight fluid bulkhead <br />earthquake load (psf) <br />to ~ =factored bulkhead concrete <br />earthquake load (psf) <br />6 s =flexural stress (psi) <br />a maX =maximum principal stress (psi) <br />v ~a =minimum principal stress (psi) <br />6 o~n =overburden stress (psi) <br />By JFA Date 9/6/03 <br />Sheet 2 of 6 <br />Inputs continued: <br />Load increase factors <br />Fluid static load, ~ fs := 1.40 <br />Earthquake acceleration, static fluid <br />load <br />Eart~rquake acceleration load, line of <br />sight <br />fluid and bulkhead masses, <br />Bulkhead length for hydraulic pressure gradient: <br />H'Y K, <br />Maximum pressure head, t:.= 144-- psi p = 215 psi <br />~fe~=1.05 <br />~ ea ~= 1.40 <br />Allowable pressure gradient of 41 psi/ft for low-pressure (-50 psi) grouting of upper part of <br />concrete/rock contact. <br />Required bulkhead length for low-pressure grouted concrete/rock contacC := P L = 5.25 <br />41 <br />Death below surface to prevent hydofrac of rock around tunnel: <br />Allowable formation breakdown pressure, B p := p B p = 215 psi <br />Y <br />Overburden pressure, pcr ft of of depth, ~ ovb '- 144 ~ ovb = 1.143 psUft <br />Height of rock to prevent hydrofrac, Z := p Z = 94.2 ft <br />2'~ ovb <br />ft <br />~aekai~a snnsm ns~ ua <br />