b'ExternalSleeve: Another meansofincreasing It is interesting to note that the combination of thethe axial moment of inertia of the pier shaft is to PPB-350-EPS, 3-1/2 diameter pier pipe, plus theinstallexternalpiersleeving.Manydesigners PPB-350-IS Inertia Sleeve provides axial stiffnesslikethismethodbecauseitprovidesa equal to 91% of the of the PPB-400 system (4significantly larger increase in pier rigidity than diameter) system.othermethodsdiscussedhere.Thisisbecause If the designer chooses PPB-350-SB (4 diameterthe external sleeve increases the diameter of the exteriorsleeve) overthePPB-350-EPS(3-1/2pier shaft. inch diameter) pier pipe and grout fills pier pipe,Wheninstallingexternalsleeves,thesections theallowableloadonthesystemwill increasemustbepositionedsuchthatthejointsofthe 51% higher than using the PPB-400 (4 diameter)externalsleevingarestaggered awayfromthe piersystem.Thecostsavingsshouldbeverypier pipe couplings.The external sleeving must evidentespeciallyonprojectsthatrequireextrabehydraulicallydrivenovertheinstalledpier rigidity only in the upper several feet of soil.pipe prior to field load testing.The time required When specifying either type of pipe sleeve, thetodrivetheexternalpiersleevingisgenerally designer must extend the sleeving a minimumequivalent to the time required to initially install depth of three feet beyond the zone of weak soilthe pier pipe. and into the competent material.ExternalSleeving is economicalbecauseitis Forexample,ifasitehas6feetofpeatwithonly required where the pier pipe is exposed or StandardPenetrationTest(SPT),N=0bpfwhere the pipe passes through weak soil having (Weight of Hammer) to 2 bpf and this peat isinsufficient lateral support for the axial load on overlaying sand with a SPT, N 5 blows perthe pipe shaft. foot;thedesignershouldspecifysleevingtoaTable13onthepreviouspagepresentsshaft depth of at least 9 feet in order to provide adequatestiffness relative to different pier pipe and sleeve sleeveembedmentbeyondthe6foot stratumofconfigurations. weak peat.Quick-Solve Buckling Load Estimates for Weak Soil ConditionsAmethodfor instantlyestimating Estmated oftheproductlineandsoilcolumnistheMaximumConservativeWorkingLoadsin maximum Design Load (WorkingLoad) forWeakSoil canbefound inTable 12 above. that pier or pier combination. If the capacity isGeneralsoiltypesand SPT,N,valuesare unsufficient, drop down to a stiffer pier for theprovided in four columns. Ontheleftsideof job.Table12 areavailablepierpipeandsleevingconfigurations. Read horizontallyuntilthe Please remember that the values given in Tablecolumn with soil that most closely matches the 12 are Working Loads.A Factor of Safety ofsoil conditions at the job site.At the intersection 2.0 has already been applied to the loads shown.ECP Steel Pier PPB-350-TTA Utility Bracket System,With TAF-150 Torque Anchor Tieback AssemblyPIER CAPPPB-350 STANDARD ThePPB-350-TTASteelPierPPB-350 STANDARD UTILITY BRACKET Assembly isusedtoconnect a 1-UTILITY BRACKET 1/2 Square ECP Torque Anchor TRANSITION - PPB-350-TA to provide lateral stabilization to theBEARING PLATE(SQUARE BAR TOONE OR MORE ALL-THREAD) steel piersystem.TheconnectionTIEBACK EXTENSIONTIEBACK LEAD SECTIONS PPB-350-TA canalsobemadetoastandardBEVEL WASHERONE OR MORE TA-150 TORQUE PPB-350-TA PPB-350eccentricunderpinningANCHOR PIER EXTENSIONHELICAL PLATES 1-1/8" DIAMETER ASSEMBLY(1" NOMINAL) ALL- FACE PLATE bracketbypurchasing aPPB-350-THREAD BAR TAAdapter Kit.Pleasecontact3-1/2" DIAMETER ECPforfullspecificationsforthePIER PIPEFigure 5. PPB-350-TTA with installation.TAF-150 Helical Tieback AnchorECP Steel Piers - Technical Design Manual2021 Earth Contact Products, L.L.C.2021-09 Chapter 6 - Page 129 All rights reserved'