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4 <br />5FA Design Group, LLC <br />STRUCTURAL I GEOTECHNI(Al I SPECIAL INSPEC -I IONS <br />Type = Poyurethane Foam <br />lConcrete Backfill Dimensions <br />Effective Friction Angle = <br />26' <br />Passive Coefficient, Kp = <br />tan12*(45+W/2) <br />Kp = <br />2.57 <br />Passive Pressure, Pp = <br />2.57 * 100 = 257 pcf <br />Cohesion, c' = <br />1500 psf <br />Soil Unit Weight, y = <br />100 pcf <br />Depth of Backfill, d = <br />2.0 It <br />Width of Backfill. w = <br />1.5 ft <br />Depth to Backfill, r = <br />2.0 It <br />Soil Neglected = <br />1.0 ft <br />Backfill Depth Below Grade = <br />4.0 ft <br />Passive Lateral Resistance Acting on Concrete Backfill <br />Passive Pressure at Base, ap' = Pp'(d+r) <br />256.8pcf * (4 ft) = ap' = 1027 psf <br />Lateral Capacity/Pier, Rp = ((A+B)/2)*d <br />Rp=((A+B)/2)*d=((770 plf+1541 plf)/2)*2 ft = 2311 Ibs <br />1 ft NEGLECTED <br />Depth to Backfill - 1 ft = 1 ft <br />Depth of Backfill d = 2 ft <br />PROJECT NO. SHEET NO. <br />M F R 22-280 <br />DATE <br />(Kp*y*r)*w = 770 plf <br />Rp = 2311 Ibs <br />o - (KP'y'(r+d))'w = 1541 plf <br />ap' = 1027 psf <br />cwa <br />LOADING DIAGRAM PER PIER <br />Lateral Resistance per Pier <br />Concrete Backfill Spacing = <br />8.4 ft (5.61 B) <br />P-Multiplier 1 st Backfill = <br />1.00 Per AASHTO TABLE BELOW <br />P-Multiplier 2nd Backfill = <br />0.99 <br />P-Multiplier Other Backfills = <br />(INTERPOLATION OK) <br />0.82 <br />Number of Piers to Be Backfilled = <br />3 pier(s) <br />Lateral Resistance of 1st Backfill = <br />1 * 2311 Ibs = 2311 Ibs <br />Lateral Resistance of 2nd Backfill = <br />0.99 * 2311 Ibs = 2283 Ibs <br />Lateral Resistance of Other Backfills = <br />0.82 * 2311 Ibs = 1901 Ibs <br />l abk 10.7.2.a-1—Pik P-Mulfiphr P_. for Stuhipk Row Shading (­.geifr� Ilaunigau r al.., 2006) <br />I'd, ('li -tip.0 im; IIn the dhritiun of P-Mulli pliers, m <br />1­edlugl Row 1 Row' 2 Ro , i end hlpher <br />3B t3 R U <br />5H Lo 1 0.85 1 -u 77 <br />Total Lateral Resistance of Piering System <br />Lateral Resistance = 1 st Backfill + 2nd Backfill + Other Backfills + Slab + Unpiered + Passive Pressure on Footing + Pier Passive <br />Total Lateral Resistance = 2311 Ibs + 2283 Ibs + 1901 Ibs * (3 piers - 2 piers) + 0 Ibs + 0 Ibs + 198 Ibs = 6694 Ibs <br />Factor of Safety = 1.1 <br />Allowable Resistance = 6085 Ibs >4714 Ibs OK <br />Polyurethane Foam Capacity <br />Compressive Strength of Foam = <br />67.0 psi <br />Diameter of Pier = <br />2.875 in 0 <br />Area of Pier Bearing on Foam = <br />69.00 in' <br />Bearing Strength of Pier on Foam = <br />4623 lb <br />Factor of Safety = <br />2.0 <br />Bearing Strength of Pier on Foam = <br />2312 lb OK, Soil Bearing Controls <br />