MYTHS TO DISPEL
steel head post is crooked
As is well known, modern wine-growing installations are mostly made up of steel posts that, thanks to their physical and mechanical characteristics, are ideal for the use of mechanised vehicles in the production process.
The design of these structures includes the use of header posts that are often made of materials that are different from the interior posts, not for precise technical choices but more for personal beliefs and/or aesthetic issues.
In fact we find header posts made of prestressed concrete because they are resistant and durable, or wooden header posts that give the vineyard a more natural look that blends better into the surrounding landscape.
Recently, however, steel posts are also being used which, aside from giving the entire vineyard a uniform look, are also equipped with holes and slots that facilitate and speed up the securing and stringing of the support wires.
Normally they are open with a rectangular or square cross-section and are positioned with the open part facing the row.
In contrast, Valente has decided to design and produce a steel header post where the open part faces the anchor. In other words, it is mounted in the opposite direction to all the other posts currently available on the market.
Hence the rumour that the metal header posts are “crooked”, as some say, thinking they were installed incorrectly.
The truth is that this way of installing the post was chosen for a very specific reason: it doubles the mechanical strength of the post!
Let’s see why by analysing the various anchoring systems in detail.
VINEYARD ANCHORING SYSTEM
Let’s start by saying that it is called an “anchoring system” because when stressed the various elements (header post, anchor, connecting cable) behave as a single system and not as the sum of the resistances of the individual materials.
In the system shown, when the row cables are tightened the post starts to flex and the most stressed parts are the two sides of the post (see parts in red).
The two sides highlighted are subjected to compression stress, and only a small amount of lateral stress (e.g. being struck by equipment) is needed to cause the immediate crumpling and bending of the post.
In contrast, with this system when the row cables are tightened the post starts to flex and the most stressed part is the base of the post (see part in red).
The base, stressed by the tension of the cables and the weight of the grapes, is compressed but has two edges that stiffen the cross-section preventing it from deforming, even if struck by any equipment.
Moreover, this solution guarantees greater uniformity of performance between the anchored part and the part above ground as opposed to the traditional system where the presence of vertical compression and horizontal traction on the wings causes an intensely stressed area where cracks may occur in the material over the long run.
The final result is a post that, with the same size and thickness, can withstand tensions that are even 100% higher compared to a traditional system.
When we find ourselves having to advise customers on choices to be made, we always try to convey knowledge so that they can identify the best solution for them. In this case the goal of having a stronger post is not achieved by increasing its cross-section and thickness, but simply by making it work better.
For us this means orienting the customer towards a choice that is not just fact-based but safer!
You can rely on our team. We’ll be happy to put our experience at your service to help you in the best possible way!