b'Table 2. Capacities of ECP Helical Torque AnchorsInstallation Torque Axial Ultimate- Limit Useable Practical Load LimitShaft Size Factor (k) Compression Tension Strength Torsional Based on TorsionalLoad Limit Strength Strength1-1/2 Square Bar 10 70,000 lb. 70,000 lb. 7,000-lb Load limited to the1-3/4 Square Bar 10 100,000 lb. 100,000 lb. 10,000 ft-lb rated capacity of theattachments and the2 Square Bar8.5 (Compression 127,500 lb. 150,000 lb. 15,000 ft-lb lateral soil strength10 (Tension) against the shaft2-7/8 Tubular0.203 Wall LW 9 60,000 lb. 60,000 lb. 5,500 ft-lb 50,000 lb2-7/8 Tubular0.276 Wall 9 100,000 lb. 100,000 lb. 9,000 ft-lb 81,000 lb3-1/2 Tubular0.300 Wall 8 115,000 lb. 120,000 lb. 13,000 ft-lb 104,000 lb4-1/2 Tubular0.337 Wall 7 160,000 lb. 160,000 lb. 22,000 ft-lb 154,000 lbMost of ECP TA-150, TA-175, TA-288 and TA-350 Torque Anchor product lines have an ICC evaluation and ICC-ES3559 has been issued.IMPORTANT NOTES:The capacities listed for Axial Compression Load Limit, Ultimate Limit Tension Strength and Useable Torsion Strength in Table 2 are mechanicalratings.One must understand that the actual installed load capacities for the product are dependent upon the soil conditionsat a specific job site.TheUseable Torsional Strengths given here are themaximum values that oneshould apply to the product.Furthermore, these torsional ratings assumehomogeneous soil conditions and proper alignment of the drive motor to the shaft.In homogeneous soils up to 95% or more of the Useable TorsionalStrength shown in Table 2 can be applied.In obstruction-laden soils, torsion spikes may cause impact fractures of theshaft,couplings or othercomponents.Where impact loading is expected,Actual Applied ShaftTorsion should be reducedby 30% or morefrom that shown in Table 2.Whendealing with poor soil conditions on site, select a larger shaft toreduce chance of fracture or damage during installation.Another advantage of selecting a higher Useable Torsion Strength value from Table 2 is thatone may be able to drive the pile slightly deeper after thetorsional requirements have been met, thus eliminating the need to cut the pile shaft in the field.The designer should select a product that provides adequate additional torsional capacity for the specific project.and soil conditions,The k value for square bars is generally higher Equation 2: Site Specific Soil Efficiency Factorthanfortubularshafts.Keepinmindthatthe k = (T u or P u ) / Tsuggested values in Table 1 are only guidelines.Where: k = Soil Efficiency Factor - (ft -1 )ItisalsoimportanttorefertoTable2atthe T u = P u = Ultimate Capacity - (lb)beginning of Chapter 1 for the Useable Torsional (Calculated or measured from field load tests)Strength that can be applied to a specific anchor T = Final Installation Torque - (ft-lb)shaft.Beingmindfulofthetorsionalstrength An appropriate factor of safety must alwaysrating oftheshaftwillhelptoavoidshaft be applied to the design or working loadsfractures during installation. when using Equation 1 and 2.Failuretoverifythatthe chosen shaftconfigurationhassufficientreservetorsional Determining Installation TorquecapacitycouldresultinanunexpectedshaftTwistingoftheSolidSquareBar Thisfractureduringinstallationespeciallyinsoils method of torque control is the least accuratecontaining debris, rocks and cobbles. method to determine the torsion that is beingEquation 1:Installation Torque applied to the shaft.The reason this method isT = (T u or P u ) / k or (T u or P u ) = k x T inaccurate, and not recommended, is becausethepointatwhichtwistingoccurswillvaryWhere, with fluctuations in the steel chemistry used toT = Final Installation Torque - (ft-lb) makethebar,thedifferencesintorsional (Averaged Over the Final 3 to 5 Feet) strength from bar to bar within a mill run ofT u or P u = Ultimate Capacity - (lb) bars,andthetolerancesinthesteel (Measured from field load tests)k = Soil Efficiency Factor - (ft -1 ) compositions betweenmillrunsofsimilarbars.The length of shaft can also affect theTodeterminethesitespecific SoilEfficiency numberoftwistsforagivenshafttorque.Factor, (k) from field load testing, Equation 1 ECP does not recommend using this methodis rewritten as: to determine installation torque.ECP Technical Design Manual - Installation & Testing2021 Earth Contact Products, L.L.C.2021-09 Chapter 4 - Page 62 All rights reserved'