b'Equation 1a Where:Ultimate Capacity - Cohesive Soil P uor T u = Ultimate Cap. of Torque Anchor- (lb)P uor T u = A H(9c) or A H= P uor T u / (9c) A H = Sum of Projected Helical Plate Areas (ft 2 )c = Cohesion of Soil - (lb/ft 2 )Graph 1. REQUIRED HELICAL PLATE AREA vs. SPT, "N"Cohesive Soils109 10 kip. Ult. Cap.8 20 kipUlt. Cap.Helical Plate Area - sq.ft.40 kipUlt. Cap.7 80 kipUlt. Cap.654 Earth Contact Products32102 4 8 15 20 30Standard Penetration Test - "N"Graph 1 may be used to quickly get a rough estimate of the plate area requirements for piles and anchorsin cohesive (clay & silty) soils based upon Standard Penetration Test, N, values at the terminationdepth of the pile or anchor.One may also use Graph 1 to compare results obtained from Equation 1a.Cohesionless Soil (Sands & Gravels)In cohesionless soil, particles of sand act independently of each other.This type of soil has fluid-likecharacteristics.When cohesionless soils are placed under stress they tend to reorganize into a morecompact configuration as the load increases.Cohesionlesssoilsachievetheirstrengthand Table 6. Cohesionless Soil Classificationcapacity in several ways. Soil Description USCS The soil density Symbol The overburden pressure (The unit weight of Well Graded Gravel Or Gravel-Sand GWthe soil above the Torque Anchor) Poorly Graded Gravel Or Gravel-Sand GP The internal friction angleSilty Gravel Or Gravel-Sand-Silt Mixtures GMSoilOverburdenPressure q: Thesoil Clayey Gravel Or Gravel-Sand-Clay Mixtures GCoverburdenpressureatagivendepthisthesummation of density(lb/ft 3 ) of each soil layer Well Graded Sand Or Gravelly-Sands SWmultiplied by its thickness, h.The moist density Poorly Graded Sand Or Gravelly-Sands SPof the soil is used when calculating the value ofqforsoilsabovethewatertable. Belowthe Silty Sand Or Sand Silt Mixtures SMwatertablethebuoyancyeffectofthewater Clayey Sands Or Sand-Clay Mixtures SCmustbetakenintoconsideration.Thesubmerged density of the soil where all voids in helicalplateofaTorqueAnchor,thevalueofthe soil have been filled with water is determined q platefor each stratum of soil must be determinedby subtracting the buoyant force of the water (62.4 fromtheintendedfinalsurfaceelevationtothelb/ft 3 ) from the moist density of the soil.To arrive helical plate elevation, h plate .By using Equationat value for soil overburden pressure on a singleECP Helical Torque Anchors Technical Service Manual2021 Earth Contact Products, L.L.C.2021-09 Chapter 1 - Page 19 All rights reserve'