The life-span of our Helicas

One of the concerns that many people have when they learn about our foundation and fixing solution is its useful life. Our Helicas, internationally known as helical piles, are steel elements placed inside the ground without resorting to the use of concrete or any cement-based material. As such, steel is in contact with the ground and with the aggressiveness it can present. In order to achieve adequate protection, there are several ways to achieve this.

Thickness of Sacrifice

Helicas have to be designed not only for the actions present during their useful life, but also for the actions arising from the installation. The latter are often constraints for some of the elements of the Helicas and as such there is an excess thickness of some elements for these actions. This over-thickness constitutes a protection to the guarantee of the useful life of the material because it can enter a corrosion process and even so be able to guarantee the design loads to which it is subject.

Surface Protection

An additional barrier to corrosion of the Helica’s material is the placement of a surface protection, which we usually provide through hot-dip galvanizing. This additional surface barrier can extend the useful life of the material and, when there are visible elements outside the ground, give the material a better finish.

Cathodic protection

With this type of protection, a material with a potential difference in relation to the Helicas is placed, electrically connected, so that it is more reactive. With this connection, the material connected, called the anode, passes electrons to the Helicas so that oxidation always occurs at the anode and not at the Helicas.

But what is the useful life of Helicas?

All the protections that can be used, discussed above, depend on the aggressiveness of the soil, which can be measured by its electrical resistivity. A soil with higher electrical resistivity offers less aggressiveness to the Helicas and vice versa. Soils with dry sands, dry gravels or granites present very low aggressiveness while marine soils, organic soils or humid clays present a high degree of aggressiveness.

The unprotected steel thickness can disappear at a rate of 1mm every 15 years, in the case of soils with high aggressiveness, or 1mm every 100 years in the case of soils with low aggressiveness. The surface protection given, in the case of Helicas, by hot dip galvanizing, can constitute an extension of the useful life period by more than 2.5x the original useful life period of the Helicas. In the case of cathodic protection and if there is no renewal of the sacrificial anodes during the useful life of the structure, this may correspond to an extension of the useful life of the elements by 10 to 20 years.

Helica continues to work to determine with great rigor the useful life of its elements in the ground and thus offer real guarantees to the market.

Need more information, do not hesitate to contact Helica.