CAPABILITIES
Helical Anchor Design
ECP Helical Torque Anchors™ are engineered for high-load, reliable performance in a wide range of soil conditions. The tables below provide key design capacities and installation guidance for ECP helical anchor systems.
Capacities of ECP Helical Torque Anchors™
| Shaft Size | Installation Torque Factor (k) | Axial Compression Load Limit | Ultimate-Limit Tension Strength | Useable Torsional Strength | Practical Load Limit Based Torsional Strength |
| 1-1/2″ Square Bar | 9 – 11 | 70,000 lb. | 70,000 lb. | 7,500 ft-lb | Load limited to the rated capacity of the attachments and the lateral soil strength against the shaft |
| 1-3/4″ Square Bar | 9 – 11 | 100,000 lb. | 100,000 lb. | 10,000 ft-lb | |
| 2″ Square Bar | 10 – 12 | 200,000 lb. | 200,000 lb. | 23,000 ft-lb | |
| 2-7/8″ Tubular – 0.262″ Wall | 8 – 9 | 100,000 lb. | 100,000 lb. | 9,500 ft-lb | 80,000 lb |
| 3-1/2″ Tubular – 0.300″ Wall | 7 – 8 | 115,000 lb. | 120,000 lb. | 13,000 ft-lb | 97,000 lb |
| 4-1/2″ Tubular – 0.337″ Wall | 6 – 7 | 160,000 lb. | 160,000 lb. | 22,000 ft-lb | 143,000 lb |
| *See IBC Section 2117 | |||||
Projected Areas* of Helical Torque Anchor™ Plates
| Helical Plate | 6″ Dia. | 8″ Dia. | 10″ Dia. | 12″ Dia. | 14″ Dia. | 16″ Dia. |
| Shaft | Projected Area – ft2 | |||||
| 1-1/2″ Sq. | 0.181 | 0.333 | 0.530 | 0.770 | 1.053 | 1.381 |
| 1-3/4″ Sq. | 0.175 | 0.328 | 0.524 | 0.764 | 1.048 | 1.375 |
| 2-1/4″ Sq. | 0.161 | 0.314 | 0.510 | 0.750 | 1.034 | 1.361 |
| 2-7/8″ Dia | 0.151 | 0.304 | 0.500 | 0.740 | 1.024 | 1.351 |
| 3-1/2″ Dia | 0.130 | 0.282 | 0.478 | 0.719 | 1.002 | 1.329 |
| 4-1/2″ Dia | 0.086 | 0.239 | 0.435 | 0.675 | 0.959 | 1.286 |
| *Factor area is a theoretical projected area of the helix/plate. Actual surface area can be as much as 10% of theoretical area. | ||||||
Allowable Mechanical Helical Plate Capacities
| 6″ through 14″ Diameter Plates | ||
| Helical Plate Thickness | Average Ultimate Load | Average Working Load |
| 3/8″ | 40,000 lb | 20,000 lb |
| 1/2″ | 50,000 lb | 25,000 lb |
| 16″ Diameter Plate | ||
| 1/2″ | 40,000 lb | 20,000 lb |
| Note: Assumptions for K 1 (1.0″ “actual” pitch), anchor in clean, loose, free-draining sand (no clay). Performance may be reduced if anchors are loaded in soil conditions with which the helix(es) will not achieve full bearing resistance. | ||
Installation Torque Factor "k"
| Torque Anchor™ Type | Estimated Empirical Torque Factor Range – “k” |
| 1-1/2″ Solid Square Bar | 9 – 11 |
| 1-3/4″ Solid Square Bar | 9 – 11 |
| 2-1/4″ Solid Square Bar | 10 – 12 |
| 2-7/8″ Diameter Tubular | 8 – 9 |
| 3-1/2″ Diameter Tubular | 7 – 8 |
| 4-1/2″ Diameter Tubular | 6 – 7 |
| Important: Installation torque is required to achieve the anchor’s ultimate capacity. Installation in hard dense, cobbles or mixed, oversize conditions may require field verification. K = Installation Torque Factor Load D = Anchor Shaft Diameter (inches) HP = Helix Pitch (inches) T = Installation Torque (in-lb) D = Helix Outside Diameter (inches) P = Projected Horizontal Area of the Helix (in²) F = Projected Horizontal Area of the Plate (in³) *Helix (s) and/or plate sizes can impact installation torque range; deviations see testing handbook. |
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