Hendriks precon helps build expansion of 380 kV high voltage gridFormwork for footings of power pylons

Given the changing energy landscape, work on expanding the high voltage grid has become a common sight. For example, a new 380 kV high voltage line is being constructed in the Northern Netherlands using Wintrack-type power pylons. Hendriks precon is supplying round formwork in various diameters and heights for the foundation footings.

Expansion of the high voltage grid

The electricity grid is being modified at various locations in the Netherlands. An example of this is the port of Eemshaven, an area where a great deal of renewable energy is being generated and brought onshore. Multiple power plants are located here to which the cabling from Norway and Denmark and the current and future solar parks and wind farms are or will be connected. All of this electricity must be transmitted over the Dutch national high voltage grid. That means its transmission capacity must be increased.

TenneT is responsible for managing the high voltage grid in the Netherlands. This company, which also serves large parts of Germany, transmits electricity at 110 kV and higher. TenneT, for the expansion of the high voltage grid in the Northern Netherlands, in particular the 380 kV Eemshaven-Vierverlaten high voltage lines, awarded the construction of the required civil works to BAM Infra Nederland and to a consortium consisting of Mobilis and Strukton Civiel. Both parties engaged Hendriks precon for the footing formwork for the many new Wintrack pylons that form part of this contract.

Comprehensive delivery

The footings for the power pylons are of different diameters and heights. Romke Wielstra of BAM Infra Nederland: “The formwork is supplied in two sets. One set has a 1.75 m height and an adjustable diameter of between 8 and 10 metres. The diameter of the second set can be adjusted in increments of 1 metre from 13 to 16 metres. Its height is 3 metres. Each mould consists of 8 segments. Furthermore, the solution provided by Hendriks precon is entirely circular: the company increased the height of one of the moulds we still had from one of our previous projects, from 1.5 metres to 3 metres. This way it can now be used for this project as well. For safety purposes, the moulds are equipped with safety fences, including integrated (cage) ladders. A transport frame, specifically developed for this purpose by Hendriks precon, is used to transport the parts from one pylon foundation to another.”

Sustainable solution

The Mobilis and Strukton Civiel consortium is also making use of the moulds. Hylke Hesselius of Mobilis: “We will be making intensive use of the moulds for the pylon footings for about eighteen months. That requires a sustainable solution that can be used more than one hundred times. That is definitely possible with these moulds. Furthermore, the moulds are very easy to use. As a result the foundations can be constructed with minimum effort. The parts are easily assembled using several high-quality reamed bolts. This eliminates the need for bracing or centring; the formwork is simply placed around the braided rebar after which the concrete can be poured right away. We use magnetic bevelled batten to indicate the height to which the concrete is to be poured. In addition, the trestles we use not only simplify transport from one location to the next, they also guarantee that the parts stay perfectly intact and clean during the period of use. In short, a comprehensive solution that is easy for us to work with. This is the first time we are working with Hendriks precon and we are very satisfied!”