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c SFA Design Group, LIE <br /> 5 fit PROJECT NO. SHEET NO. <br /> STRUCTURAL I GEOTECHNICAL I SPECIAL INSPECTIONS MFR23-236 <br /> PROJECT DATE <br /> Bankston Residence Underpinning 3/1/2024 <br /> SUBJECT BY <br /> Concrete Backfill(s)Along Gridline A CAF <br /> Backfill Information <br /> Backfill Type= Polyurethane Foam <br /> LConcrete Backfill Dimensions <br /> Effective Friction Angle= 26° <br /> Passive Coefficient,Kp= tanA2*(45+0'/2) siEwui <br /> Kp= 2.57 rN4 cR+dE <br /> Passive Pressure,Pp= 2.57*100=257 pcf �k ., �:•r.'.` <br /> Cohesion,c'= 1500 psf <br /> IIEI <br /> Soil Unit Weight,y= 100 pcf s lII- 6111111. A <br /> Depth of Backfill,d = 2.0 ft " III-IIEIIEIII�t1T:V III�t11E1TElIl- antic <br /> 1-11— —u t •.11=_111E11111 <br /> Width of Backfill,w = 1.5 ft 9—IIE111=11 {'{ .I_IIEIIEIII <br /> Depth to Backfill,r= 2.0 ft -ll ri?; - - <br /> Soil Neglected= 1.0 ft a 1.1,• <br /> Backfill Depth Below Grade= 4.0 ft ^ ' <br /> Passive Lateral Resistance Acting on Concrete Backfill <br /> Passive Pressure at Base,op'=Pp*(d+r) <br /> 256.8pcf*(4 ft)=op'= 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 lbs <br /> 1 ft NEGLECTED <br /> Depth to Backfill-1 ft=1 ft <br /> A= (Kp*y*r)*w= 770 plf <br /> Rp=2311lbs <br /> Depth of Backfill d=2 ft <br /> B=(Kp*y*(r+d))*w= 1541 plf <br /> ap = 027 psf <br /> LOADING DIAGRAM PER PIER <br /> Lateral Resistance per Pier <br /> Concret <br /> e Backfill Spacing= 0.0 ft (OB) <br /> P-Multiplier 1st Backfill= 1.00 Per AASHTO TABLE BELOW <br /> P-Multiplier 2nd Backfill= N/A (INTERPOLATION OK) <br /> P-Multiplier Other Backfills= N/A <br /> Number of Piers to Be Backfilled= 1 pier(s) <br /> Lateral Resistance of 1st Backfill= 1*2311 lbs=2311 lbs <br /> Lateral Resistance of 2nd Backfill= N/A <br /> Lateral Resistance of Other Backfills= N/A <br /> Table 10.7.2.4.1—Pile 1•hiultlpOrrs,Pm,for Multiple Row Shading(averaged from Hannigan et al.,1IN]G) <br /> Pile LTC spacing On the direction of P-h1ulllplleis,P,,, <br /> loading) Row I Row 2 Row 3 and higher <br /> 3B 0.8 0.4 0.3 <br /> 5B 1.0 0.85 0.7 <br /> Total Lateral Resistance of Piering System <br /> Lateral Resistance=1st Backfill+2nd Backfill+Other Backfills Slab+U npiered+Passive Pressure on Footing+Pier Passive+Tiebacks <br /> Total Lateral Resistance=2311Ibs+Olbs+Olbs+0 lbs+0 lbs+198 lbs+0 lbs+0 lbs=2509 lbs <br /> Factor of Safety= 1.1 <br /> Allowable Resistance= 2281 lbs >2148 lbs OK <br /> Polyurethane Foam Capacity <br /> Compressive <br /> i . <br /> Strength of Foam= 67.0 psi <br /> Diameter of Pier= 2.875 in 0 <br /> Area of Pier Bearing on Foam= 69.00 in0 <br /> Bearing Strength of Pier on Foam= 4623 lb <br /> Factor of Safety= 2.0 <br /> Bearing Strength of Pier on Foam= 2312 lb OK,Soil Bearing Controls <br />