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Tel: (86)757-87662928

Fax: (86)757-87662921

Email:china@pvpowerway.com

1. What's the cost of PowerScrew?

Our engineers will give you the most economical solutions depending on your racking system. Costs vary depending on several factors: such as structure to be supported, type of soil, length, area etc. Please send us your details.

2. What load can a PowerScrew bear?

The load bearing of PowerScrew is determined by the type of soil in which it is installed. The denser the soil, the greater the load bearing capacity. This capacity is determined during installation. While screwing in the last few inches, the installer checks the hydraulic pressure, using a pressure gauge located on the excavator arm. He can then determine, thanks to a precise guide chart, the screw's load bearing capacity. In loose soil, extensions may be needed to reach a more compact soil, and desired capacity.

3. What makes a 'good' ground screw?

Customers often wonder how we demonstrate that our ground screw is superior to those made by other factories. Superficially, a 'good' ground screw could simply mean that it is made of 'good' quality materials. But our definition carries a lot more meaning than that. Our ground screw is also designed to deliver the best possible performance in keeping with the various projects of our customers.
    When dealing with construction of a solar PV ground plant, a shrewd businessperson will take these elements into account:
    - Project location, climate, environment and other natural elements;
    - Completion time of installation;
    - Capital cost and economic benefit;
    - The best supplier for on-going maintenance and quality assurance.
    Keeping the above in mind, we suggest using our ground screw when a project is located far from a source of water, where there is a tight time frame for construction, and where soil conditions allow such installation. Our experience building three large-scale ground power plants has shown us that, when compared to a traditional concrete foundation, the ground screw system has several exceptional points in its favour. For example, ground screw installation time is a quarter that of a concrete foundation, and the manpower requirement is one third. Especially in times of inflation, the human labour saving alone is a compelling reason to use this superior method. Businesspeople today need to maximize their investment by using efficient, advanced mechanized equipment. At the start of a project, Powerway immediately sends engineers into the field to make an on-site inspection and evaluate the potential for ground screws. Once the review is done, our engineers will design an optimal foundation and racking system that ensures construction permanence. When we say our product is 'good' it means 'best fit '. Those who collaborate with Powerway will experience our 'good' service and 'best fit' business culture.

4. Can PowerScrew be installed in rock?

Yes, Powerway has developed the technology to drive the screw into rock.

5. C post foundation versus ground screw?

There is a huge difference between the C post foundation and ground screw system:
    1. Ideal to use ground screw when soil conditions are 'hard' (not suitable for driven piles).
    2. Ideal to use ground screw for 'monopost' structure (one foot instead of two) for higher resistance loads.
    3. C-post needs some deeper perforation, but not much more if soil conditions are adequate.
    4. Number of legs / feet should be the same as per ground screw. This depends on the static load design of the whole system.

6. Can we install PowerScrew by ourselves?

Yes, Powerway will provide proper equipment and installation instructions.

7. Concrete foundation versus ground screw?

Concrete foundation versus ground screw?

8. How much should the ground screw protrude?

Generally, that will depend on the business owner's requirements. If the owner does not specify, Powerway's engineering team will calculate a practical height based on the results of field study, integrated terrain, sun altitude, cost, and flood tide analysis etc., and implement it with the owner's permission.

9. What kind of soil requires a concrete foundation?

When soil contains over 70% stone a concrete foundation should be used.
What kind of soil requires a concrete foundation?

10. What type of soil is suitable for screw installation?

What type of soil is suitable for ground screw installation?

11. What's the best distance between 2 PowerScrews?

Typically it is 245cm to 305cm between 2 ground screws.

12. What's the general range of PowerScrew wall thickness?

Usually 2.8-3.5mm.

13. Does every PowerScrew need an insulation layer (sleeve)?

No, this is not necessary.

14. Can PowerScrew be installed under an existing structure?

Yes, it is possible to install PowerScrew under an existing structure. However, the proposed location of the screw must be relatively close to the edge of the structure. If the screw must be installed in the middle of a structure, there would have to be access. For example, in the case of a wood patio, the customer may remove floorboards to allow installation of screws.

15. What is the solution when screws hit stones during drilling?

In such a case, we will use down-hole drilling. Based on field soil compactness we will decide whether to backfill the soil or fix by grouting.

16. If the road has an asphalt surface, can we use PowerScrew?

Yes, it's possible. A hole, however, must be made where the screw will be installed. Afterwards, a slight touch-up of the asphalt around the screw will be needed.

17. If there is rock discovered during installation, what can we do?

Powerway has drilling machines valued at over 300,000 RMB equipped with different drilling heads, to provide specific depth drilling in all kinds of excavations. In the overwhelming majority of cases, the installer can maneuver around the rock. If the rock is too large, and construction parameters allow, the ground screw may be installed at another location. When a screw must be installed in a precise location, excavation may become necessary, but such cases are rare.

18. Does each site determine the galvanized steel thickness to be used?

No, there is no direct relationship between the site and the galvanized screw thickness. Firstly, the model of screw selection depends on soil geotechnics and screw structure design. Galvanizing a screw makes it anticorrosive and extends its useful life, so we pay keen attention to steel quality and profile type. Lastly, the longer a screw is galvanized, the thicker the protective layer is.

19. Is it necessary to leave enough space between the soil and the structure?

Yes, It is very important to leave sufficient space between the soil and the structure (including trellises, stairs, etc.), to allow for movement of soil during frost. If the structure is in contact with the soil, then the screw's effectiveness is limited, because the frost will make the soil heave and move the structure.

20. To avoid the impacts of frost, is it necessary to have a protective coating?

Absolutely not, frost has no impact on the galvanized steel shaft. It is the base of the screw (blade) which acts as an anchor, and which prevents the screw moving due to frost heave. This is why the screw must be installed so that the blade is BELOW the frost line.

21. How do you calculate the PowerScrew structure is stable? Is a formula provided?

Yes. We have statistics for static loads. When we know the load requirements for the racking structure, we can provide screw recommendation. On site tests, monitored by a civil engineer, will confirm our assumptions or determine any changes.

22. What's the general range of the hot-dip galvanized thickness on the PowerScrew?

Generally speaking, 60-90μm.

23. Can we install ground screws in backfilled soil? What conditions should be considered?

Yes we can. But before we install ground screws in this soil we need to pre-treat the backfill as follows:
    1. Layered rolling: To a thickness of approximately 30cm.
    2. Exchange fill: remove the backfilled soil and refill with spodosol or big grain size gravel to improve bearing capability.
    3. Tamping method: reinforce the compactness of backfilled soil.
    4. Gravel press-in: tamp gravel into backfilled soil to strengthen.
    5. Pouring cement paste: pour cement paste around ground screw to improve bearing capability.

24. How many types of tests does Powerway do to check the integrity of PowerScrew, besides the tension test?

We test compression, tension and lateral strength. The number of tests depends on the project size and overall soil conditions, based on a soils report.

25. What screw models does Powerway produce? What is the material quality? What is the galvanized thickness?

There is no single answer because our firm is continually developing new models, and each model is different.

26. If you drive the ground screw into the soil a second time, after pulling it out, will there be an influence on load bearing?

Yes. That's why we must carefully train and certify our installers. Untrained people can easily ruin a project.

27. How do you prevent PowerScrew from subsidence if using bolts and screws to fasten tightly to rack poles (columns) instead of the flange?

When the system is designed properly this will not happen.

28. Is there any relationship between the spiral thread and the foundation soil or screw surroundings? For instance, in lose soil would you install a screw with bigger thread?

No. Thread type is consistent, but in lose soil you will need a larger diameter screw to ensure lateral strength.