Ground bolts have been known in Europe since the early 1980s, although they have never gained popularity in Poland. This unique foundation system has several undeniable advantages. The bolts, unlike concrete solutions, do not require an excavator and excavation, are installed quite quickly (several minutes apiece) and can be loaded immediately after screwing in. They work perfectly well where heavy equipment cannot be driven in or landscaping work has already been completed (gardens, green areas). Screws are quite often used as foundations for lightweight garage structures, gazebos, piers, landscaping structures, lampposts. AluPro has good experience in using ground bolts as an inexpensive and effective way of founding small and medium-sized towers and telecommunications masts. Our in-house tests have shown that a two-meter-long soil bolt embedded in less-than-perfect, construction-stirred soil is capable of transferring a pullout force of 1.2 tons. The disadvantage of foundation with soil bolts is precisely the inhomogeneity of the soil, as a result of which the bolts have a considerable dispersion of the forces they are able to transfer. Ground bolts should not be used in clayey soils, and in the case of high groundwater levels. It is a good tradition to perform a load test of the bolt to the level required by the structure. AluPro has the equipment and experience to drive screws as well as conduct load tests with real force measurements.
Features of ground screws:
- They can be used for both towers and masts,
- Express installation - about 3 hours per tower (2 or 3 people),
- There is no need for an excavator or heavy equipment,
- High cost effectiveness,
- Cannot be used when the groundwater level is higher than the length of the screw,
- Do not use in plastic soils including clay,
- Material - s235 hot-dip galvanized Steel,
- In good soil conditions, the bolts can withstand about 10 tons of pulling (GS76-200),
- It is recommended to test the bolt for pull-out force (breaking the thread) - AluPro S.C. provides such a service,
- Additional information for static engineers, or architects upon request,
Basic technical information:
| Bolt Model | Material | Pipe diameter [mm] x wall [mm] | Flange diameter [mm] x thickness [mm] | Length [mm]. | Thread thickness [mm] x width [mm] x pitch [mm] | Weight [kg] | Compatibility with towers *** |
|---|---|---|---|---|---|---|---|
| GS50-160 | S235 galvanized | 51×3 | 126×10 | 1600 | 3 x 10 x 50 | 7 | max T500-12, max T1000-8 |
| GS76-200 | S235 galvanized | 76×3 | 148×15 | 2000 | 3 x 15 x 50 | 14 | max T500-16, max T1000-12 |
| GS89-240 | S235 galvanized | 89×5 | 212×15 | 2400 | 3 x 18 x 50 | 29 | max T500-20, max T1000-16 |
*** Suggested compatibility for optimal soil conditions, always consult an architect, geological survey or pull-out test (offered by AluPro)
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