Allowable displacement limits. Criteria establishing the maximum amount of displacement of a material, assembly, or component under load.
Certification test site. A site used for the purpose of anchor assembly qualification testing in accordance with this section.
Cohesive soil. A soil with sufficient clay content to exhibit substantial plastic behavior when moist or wet (i.e., able to be readily molded or rolled into a 1/8 -inch thread at a wide range of moisture contents).
Ground anchor manufacturer. Any person or company engaged in manufacturing or importing ground anchor assemblies.
Non-Cohesive soil. Sand, gravel, and similar soils that are predominantly granular and lack a sufficient quantity of fine, clay-sized particles to exhibit the behavior of cohesive soil as defined in this section.
Ultimate anchor load. The lower of either the highest load achieved during an individual test prior to failure due to exceeding allowable displacement limits or the load at failure of the anchoring equipment or its attachment point to the testing apparatus.
Working anchor load. The ultimate anchor load in pounds divided by a factor of safety of 1.5.
Note to paragraph (b)(6): As a recommended practice, the test rig soil reactions (bearing pads) should not be located closer to the center of the anchor assembly (anchor head) than the lesser of D, 4d, or 32 inches where D is the depth of the anchor helix and d is the diameter of the anchor helix, both in inches. However, experience with a particular test rig, types of anchors, and soil conditions may justify other acceptable dimensional tolerances.
Note to paragraph (b)(8). Additional testing at angles of pull greater than the minimum angle of pull may be used to provide design values for specific angles of pull greater than the minimum angle for which evaluation is sought.
Notes:
Notes:
Table 1 to § 3285.402 -Maximum Diagonal Tie-Down Strap Spacing, Wind Zone I
Nominal floor width, single section/multi-section | Max. heightfrom ground to diagonal strap attachment | I-beam spacing 82.5 in. | I-beamspacing 99.5 in. |
12/24 ft. 144 in. nominal section(s) | 25 in | 14 ft. 2 in | N/A. |
33 in | 11 ft. 9in | N/A. | |
46 in | 9 ft. 1in | N/A. | |
67 in | N/A | N/A. | |
14/28 ft. 168 in. nominal section(s) | 25 in | 18 ft. 2in | 15 ft. 11 in. |
33 in | 16 ft. 1 in | 13 ft. 6 in. | |
46 in | 13 ft. 3 in | 10 ft. 8in. | |
67 in | 10 ft. 0 in | N/A. | |
16/32 ft. 180 in. to 192 in. nominal section(s) | 25 in | N/A | 19 ft. 5in. |
33 in | 19 ft. 0 in | 17 ft. 5 in. | |
46 in | 16 ft. 5 in | 14 ft. 7 in. | |
67 in | 13 ft. 1 in | 11 ft. 3 in. |
Notes:
Table 2 to § 3285.402 -Maximum Diagonal Tie-Down Strap Spacing, Wind Zone II.
Nominal floor width, single section/multi-section | Max. height from ground to diagonal strap attachment | Near beam method I-beam spacing | Second beam method I-beam spacing | ||
82.5 in. | 99.5 in. | 82.5 in. | 99.5 in. | ||
12 ft/24 ft. 144 in. nominal section(s) | 25 in | 6 ft. 2 in | 4 ft. 3 in | N/A | N/A |
33 in | 5 ft. 2 in | N/A | N/A | N/A | |
46 in | 4 ft. 0 in | N/A | N/A | N/A | |
67 in | N/A | N/A | 6 ft 1 in | 6 ft 3 in | |
14 ft/28 ft. 168 in. nominal section(s) | 25 in | 7 ft. 7 in | 6 ft. 9 in | N/A | N/A |
33 in | 6 ft. 10 in | 5 ft. 9 in | N/A | N/A | |
46 in | 5 ft. 7 in | 4 ft. 6 in | N/A | N/A | |
67 in | 4 ft. 3 in | N/A | N/A | N/A | |
16 ft/32 ft. 180 in. to 192 in. nominal section(s) | 25 in | N/A | 7 ft. 10 in | N/A | N/A |
33 in | 7 ft. 6 in | 7 ft. 2 in | N/A | N/A | |
46 in | 6 ft. 9 in | 6 ft. 0 in | N/A | N/A | |
67 in | 5 ft. 4 in | 4 ft. 7 in | N/A | N/A |
Notes:
Table 3 to § 3285.402 -Maximum Diagonal Tie-down Strap Spacing, Wind Zone III.
Nominal floor width, single section/multi-section | Max. height from ground to diagonal strap attachment | Near beam method I-beam spacing | Second beam method I-beam spacing | ||
82.5 in. | 99.5 in. | 82.5 in. | 99.5 in. | ||
12 ft./24 ft. 144 in. nominal section(s) | 25 in | 5 ft. 1 in | N/A | N/A | N/A |
33 in | 4 ft. 3 in | N/A | N/A | N/A | |
46 in | N/A | N/A | N/A | N/A | |
67 in | N/A | N/A | N/A | N/A | |
14 ft./28 ft. 168 in. nominal section(s) | 25 in | 6 ft. 2 in. | 5 ft. 7 in | N/A | N/A |
33 in | 5 ft. 8 in | 4 ft. 9 in | N/A | N/A | |
46 in | 4 ft. 8 in | N/A | N/A | N/A | |
67 in | N/A | N/A | N/A | N/A | |
16 ft./32 ft. 180 in. to 192 in. nominal sections | 25 in | N/A | 6 ft. 3 in | N/A | N/A |
33 in | 6 ft. 1 in | 5 ft. 11 in | N/A | N/A | |
46 in | 5 ft. 7 in | 5 ft. 0 in | N/A | N/A | |
67 in | 4 ft. 5 in | N/A | N/A | N/A |
Notes:
Appendix to § 3285.402
Torque Probe Method for determining soil classification: This kit contains a 5-foot long steel earth-probe rod, with a helix at the end. It resembles a wood-boring bit on a larger scale. The tip of the probe is inserted as deep as the bottom helix of the ground anchor assembly that is being considered for installation. The torque wrench is placed on the top of the probe. The torque wrench is used to rotate the probe steadily so one can read the scale on the wrench. If the torque wrench reads 551 inch-pounds or greater, then a Class 2 soil is present according to the Table to 24 CFR 3285.202(a)(3) . A Class 3 soil is from 351 to 550 inch-pounds. A Class 4A soil is from 276 to 350 inch-pounds, and a Class 4B soil is from 175 to 275 inch-pounds. When the torque wrench reading is below 175 inch-pounds, a professional engineer should be consulted.
24 C.F.R. §3285.402