One of the most challenging situations in which to install a foundation is in the case of unstable soil. Typical foundations depend upon the strength of the soil to support the structure that is being built. Foundation stem walls and footing transfer the building’s weight to the ground. The footing is constructed wider than the stem wall in order to spread the weight out, so that the ground can support it better.

Grade beams on Postech screw piles

When the ground is not able to support the necessary weight, the most common method of constructing a foundation is to use a grade beam. These concrete beams, which can either be above the ground or below the surface, transfer the weight of the building to support piles of one type or another.

In addition to using grade beams for supporting structures built on unstable or soft ground, they may also be needed in some industrial applications, to support heavy equipment or isolate it from vibration. Some medical applications, such as MRI scanners, also require the isolation that grade beams provide in order to provide a clear image.

Grade beams on screw piles

For concrete beams to function as grade beams, they must be constructed extremely rigid, with minimal deflection. This is different than designing other foundations, which are predominantly intended to transfer weight to a footing. Concrete, like any stone, is naturally strong in compression but weak in tension. To compensate for this weakness, the beams must be strengthened extensively with rebar along their bottom side. This prevents the load of the building from causing cracking in the grade beam.

Postech Screw Piles make a superior choice of support for grade beams, rather than driven or concrete piles. The ease of installation of Postech Screw Piles, along with their inherent strength, supports the load from the grade beams effectively, thus making a secure foundation that just won’t move.

When using concrete piles in unstable soil conditions, the excavation needed can be quite extensive. The lack of stability of the soil itself causes a high probability of a bored hole collapsing. This problem is eliminated with screw piles, as no hole has to be bored. When using driven piles in unstable soil, the piles must be driven deep until they hit bedrock or some other stable support, therefore adding considerable cost. This problem is also eliminated with screw piles, which don’t have to be driven as deep as driven piles.

You’ll need a grade beam soon? Why not contact your Postech representative and find out what he can do for you. After all, we’re the Screw Pile experts since 1995 and we know what we’re doing!


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