Soil Classification

Soil Classification The following soil classifications in Table I have been adopted for the purpose of determining design loads, specifications and holding power of anchors and tie down devices. Table I Soil Classification Soil Class Types of Soils Blow Count (ASTM) Test Probe (1) Torque Value (2) I Sound hard rock; Very dense and/or cemented …. N/A N/A II Sands, coarse gravel and cobles, preloaded silts, clays and corals… 40 and up More than 550 lbs.-in. III Medium-dense coarse, sands, sandy gravel, very stiff silts and clays…. 24-39 350-549 lbs.- in. IV(4) Loose to medium dense sands, firm to stiff clays and silts, alluvial fill….. (3) 14-23 (3) 200-349 lbs. – in. V Peat, organic silt, inundated silts, loose fine sand, alluvium, loess, varied clays, fill, fly ash…. 0-14 0-200 lbs. – in. (1) The soil test probe (See Figure 7) is a device for measuring the torque of soils to assist in evaluating the holding capacity of the soils in which the anchor is to be placed. The test probe has a helix on its end. The overall length of the helical section is 10.75 inches; the major diameter is 1.25 inches; the minor diameter is 0.81 inches; the pitch is 1.75 inches. The shaft of the test probe must be of suitable length and marked for proper determination of the anchor depth. Figure 7. Soil test probe equipment. (2) A measure synonymous with the moment of a force when distributed around the shaft of the test probe. (3) Below these values a registered professional engineer must be consulted. (4) A C-4 anchor must be used unless the soil is tested with a soil test probe and the readings allow for another soil type anchor to be used. (5) No previously installed or existing ground anchors that have been removed shall be reused for the installation of the Factory-Built home at any new installation site.