How the Load Lock holds
Most earth anchors rely on a cone of resistance: the wedge of soil sitting on top of the anchor. The Load Lock works differently. It uses a method known as planing. As upward tension is applied, the anchor rotates and planes sideways through the earth, pulling against the undisturbed soil beside the hole rather than the loose soil above it. That is what gives a 7 1/2 oz casting holding power of thousands of pounds.
Soil classification
The correct installation depth depends on the soil. Softer soils create less resistance, so the anchor must be placed deeper to reach full strength. B&R uses a nine-class scale:
| Class | Ground | Recommended anchor |
|---|---|---|
| 1 | Bedrock, solid rock | Expansion anchor |
| 2 | Dense rock, shale, hardpan | X Model or expansion anchor |
| 3 | Very dense gravel and heavy rock fill | X Model anchor |
| 4 | Dense clay, compact gravel and sand | Load Lock #88 |
| 5 | Medium-dense sandy clay, gravel | Load Lock #88 or #68 |
| 6 | Loose sand, soft clay | Load Lock #88, deeper set |
| 7 | Loose fill, wet sand | Load Lock #88, deeper set; test |
| 8 | Peat, organic soils, swamp | Site engineering required |
| 9 | Concrete pads and foundations | Concrete anchor with bolts |
Soil test probe and torque readings
A soil test probe measures sub-soil resistance without core samples. Torque probe readings of roughly 200 to 350 in-lb correspond to the Class 4 to 6 range where the Load Lock performs best. Lower readings mean softer soil and a deeper set.
Performance
| Model | Soil class | Depth | Approx. holding |
|---|---|---|---|
| #68 | 5 | 30" | 3,000 lb |
| #68 | 6 | 30" | 2,000 lb |
| #88 | 5 | 36" | 5,800 lb |
Figures are from B&R testing in virgin soil. Holding capacity varies with site conditions; test where the load is critical.
Frame tie-downs
Anchors resist uplift; frame ties stop a structure from sliding sideways on its supports. Use both.
Leveling jacks instead of blocks
Concrete blocks chip, crack and shift. B&R leveling jacks are threaded steel, stackable and adjustable, and hold their setting through freeze-thaw cycles.