2019-12-13_REVISION - M1980244 (58)

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Client Cripple Creek&Victor Gold Mining Company Project VLF2 Phase 3 Calculation Riser Pipe Design Date 10/31/2019 Done by Julie Pfeiffer Approved by Jay Janney-Moore - denotesuserinputrequired -denotes calculation result Screen Length Screen Dimensions 24 inch diameter Roscoe-Moss Shutter Screen,Stainless Steel,Standard Flow 84 slots/ft 55 in'/ft Open Area(Ap) 0.061 Flow Capacity(F)=4.8'(Ap'12`1)p'rt) 264 gpm/ft -- Surface are of blank casing=2nR•L 904.8 in'/ft Required riser flow 17,000 gpm Number of risers 3 _ Required flow per riser 5,667 gpm Minimum shutter screen length 21.5 ft Design Screen Length 22.0 h Downdrag r a� h=backfill height 90 ft dry unit weight 110 pcf backfill(phi)angle of internal friction 35 degrees -r�oFec"ri .¢iiw W` lateral earth pressure coeff=Ko=1-Sin(phi) 0.426 w=water content 10% wet unit weight=dry density'(1+w) 121 pcf average lateral stress=1/2'Ko•h'unit weight 2,322 psf maximum lateral stress=Ko•h•unit weight 4,644 psf Pipe Collapse Strength I-1 Pipe Wall Thickness(t) 0.375 in Pipe Outer Diameter(Dp) 24.0 in Pipe inner diameter 23.25 in - Poisson's Ratio(u) 0.3 . Young's Modulus(E) 3.E+07 psi Collapse Pressure,Timoshenko's Formula(P„) 263.69 psi 37,971 psf FOS 8.18 Shear Traction Stress Interface Friction(phi)b/w gravel and steel 17 degrees Shear Traction Stress=normal stress.tan(interface phi) 709.87 psf •� Shear traction area 565.49 sf Shear force on pipe 401,421 Ibs �- Pipe Axial Load ~' 1 Yield Strength,mild steel(S) 35,000 psi Max yield load(Y) 974,139 Ibs �p Weight of pipe(from Roscoe Moss Tables) 94.62 lb/ft Pipe self weight(loft higher than backfill) 9,462 Ibs . Axial thrust=shear traction+pipe self weight 410,883 Ibs CHECK VS MAX YIELD LOAD OK OK if actual axial thrust<max yield load ' FOS Buckling -. . max yield/actual yield 1 2.37 .. - Use this Calculation Spreadsheet to size the length of a pre-slotted shutter screen based off a given flow and to check size and strength of x - httos://roscoemoss.com/technical-resources/calculators/ A.ap I Shear Pins for Compression Joint _ Assuming Carbon Steel bolts Size bolts to support weight of riser steel casing+25%for handling dynamic loads (the riser pipes have been designed with 2 4-pin sets at each joint,to be conservative pins have been designed for a single set to carry the loa Weight of pipe(from Roscoe Moss Tables) 94.62 lb/ft Compression joint distance below top of riser 37 ft Weight of pipe at compression joint 3,501 Ibs --- -- Design load(25%additional weight) 4,376 Ibs Per pin design load(1/4) 1,094 Ibs yield strength of bolts 36,000 psi Solve for D[shear stress=(4•F)/(rt'd2)] 0.197 inches F Design Pin Diameter(SAE J429 Grade 1 bolts/studs) 0.250 inches