b'Design Example 3Basement Wall Tieback Anchor Cohesive SoilStructural Details: Cast concrete basement wall is 8 ACTIVEPASSIVE FAILUREfeet tall and 10 inches thick. PLANES FAILUREPLANE UnknownsoilbackfillagainstACTIVE SOILthe wall is 7 feet high PASSIVE EARTH PRESSURE AREAPRESSURE AREA The only soil information aboutthesiteisthatthereexistsinorganic clay (CL), stiff to very T UCRITICALstiff115 pcf EMBEDMENT INSTALLATIONDEPTH - "D" ANGLE TIEBACKTorqueAnchorDesign: LARGEST HELICAL PLACEMENTPLATE DIAMETER = "d" SOILBecausethereissolittle (MEASURE IN FEET)HEIGHTinformation about the soil on this"H"project, the designer will have tomakejudgmentsabouttheMINIMUM HELICAL PLATE LATERAL FORCEconditions on the site. EMBEDMENT AT THE REQUIRED OF SOIL AGAINSTINSTALLATION TORQUE = "d" x 3 WALL1. Estimate the lateral soil force (LARGEST PLATE DIA. x 3) Lo = MINIMUM HORIZONTALEMBEDMENT = H + 10d (ft)againstthewall: Equation5 - (EQUATION 10) EMBEDMENT LENGTH = L / COSChapter1is selectedbecausehydrostaticpressure mustbe (TABLE 13)assumed to be part of the reasonfor the damage to the wall.P H= 45 x (H 2 ) Figure 9.Design Example 3 Where, H = 7 ftP H= 45 x (49)= 2,205 A H = T u/ (9 x 2000 lb/ft 2 )P H= 2,205 lb/lineal foot A H= 22,050 lb / 18,000 lb/ft 22. Ultimate Tieback Capacity: Choose Torque A H= 1.23 ft 2Anchor spacing at 5 ft on center as typical for a 4.SelecttheECPHelicalTorqueAnchor damaged basement wall of unknown quality of configuration suitable for the load: Referringconstruction.UseEquation8 - Chapter1to to Table 2Chapter 1 choose the 1-1/2 soliddetermine the Ultimate Capacity on the Torque squarepileshaft. ThisshafthasanultimateAnchor. tensile strength for this job is 22,050 lb and theT u= (P H ) x (X) x FS, Where: 1-1/2 inch solid square shaft an Ultimate LimitT u= Ultimate Tieback Capacitylb Tension Strength rating of 70,000 pounds and aP H= Horizontal Soil Force on Walllb/lin.ft Useable Torsional Strength of 7,000 ft-lbs.FS = Factor of Safety (Typically 2:1 permanent Looking at the product tables following Table 2support and 1.5:1 for temporary support) one can easily see on Chapter 1Page 6 that aX = Center to Center Spacing of Tiebacks - ft 10 and a 12 diameter helical plate on a 1-1/2In this example, the ultimate capacity becomes: inch solid square shaft offer a plate area of 1.30T u= 2,205 lb x 5 ft x 2 ft 2 .The lead designation is TAF-150-60 10-12.T u= 22,050 lb Asanalternate,referto Table10 Chapter13. Select the proper bearing capacity equation (See below) and select a combination of plates intherowoppositethe1-1/2solidsquareshaftand collect the known information: Because size that add to at least 1.23 ft 2of bearing area.thesoilonthesiteiscohesive,Equation1aThecombinationof a 10and a12diameterChapter 1 is used: plate on the 1-1/2 solid square shaft provides aA H= T u/ (9c), totalareaof1.30ft 2 ,whichexceedsourWhere: T u= 22,050 lb calculated area requirement of 1.23 ft 2 .c = 2,000 lb/ft 2 TheTorqueAnchortiebackproduct(Table 5 - Chapter 1 Stiff to Very Stiff Clay) designation TAF-150-60 10-12 is selected fromtheStandardProduct Tables for the1-1/2inchECP Technical Design ManualTorque Anchor Design Examples2021 Earth Contact Products, L.L.C.2021-09 Chapter 5Page 89 All rights reserved'