Nabrabase is a very cost competitive alternative in wind farms where the concrete supply may represent a challenge. It is a new wind tower elevation foundation that consists of a tripod installed under the tubular tower, resulting in a hybrid support structure. The tubular tower segment is connected to the frame tower segment through metallic transition segment. The tower transition is manufactured in several elements that are transported separately and assembled on site by means of preloaded tension connections. Nabrabase Tripod elements are manufactured in steel and cast iron.

PRODUCTS

Nabrabase is a new wind tower elevation foundation that consists of a tripod installed under the tubular tower, resulting in a hybrid support structure. The tubular tower segment is connected to the frame tower segment through metallic transition segment. The tower transition is manufactured in several elements that are transported separately and assembled on site by means of preloaded tension connections. Nabrabase Tripod elements are manufactured in steel and cast iron.

The soil characteristics or even the availability of concrete in some emplacements might be challenging for the development of wind farms. Nabrabase solves this difficulties and, further more, significantly improves the environmental impact of the wind energy projects.

Footpring Reduction

Nabrabase Pile or Anchor rock foundation saves up to 80% CO2 emissions during the installation of the wind turbines.

Foundation Simplification

Concrete requirements for the foundation are reduced by 60%.

Fast Installation

The foundation is reduced to one week and the complete installation of a wind turbine to two weeks.

Nabrabase Cost Competitive Foundation

The Nabrabase elevation foundation portfolio offers several configurations. In all cases, foundation dimensions and costs are significantly lower than in standard tubular towers, since the large distance between columns of the tripod reduces the loads transferred to the ground. Additionally, the tripod transmit mostly only vertical forces (not bending moments, as in standard towers) what simplifies the design of the footings.

  • Pile Foundation. It is suitable for those sites where soft rock is available no deeper than 10m and consists on three independent concrete piles of 1.5m of diameter with a length, in the range of 20-30m. The estimated average time for manufacturing the full pile foundation is 4 days.
  • Anchor rock foundation. It is the best solution for those sites where hard rock is available no deeper than 3m.
    Pile foundations is formed by three independent concrete footings of 3-4 m of diameter and 1.5 m heigh that is connected to the rock through 8-12 post-tensioned rock anchors, grouted in pre-drilled holes.
  • Gravitational foundation. For sites where rock is not available close to the surface (deeper than 10m) and consists of three independent small footings, manufactured according to the standard process of conventional wind turbine foundations.
  • Multi-pile foundations are the best solution for sites with very poor bearing capacity and are formed by three independent footings supported by several piles of 0.8m of diameter.

Nabrabase Portfolio

The Nabrabase elevation foundation portfolio offers several configurations. In all cases, foundation dimensions and costs are significantly lower than in standard tubular towers, since the large distance between columns of the tripod reduces the loads transferred to the ground. Additionally, the tripod transmit mostly only vertical forces (not bending moments, as in standard towers) what simplifies the design of the footings.

  • Pile Foundation. It is suitable for those sites where soft rock is available no deeper than 10m and consists on three independent concrete piles of 1.5m of diameter with a length, in the range of 20-30m. The estimated average time for manufacturing the full pile foundation is 4 days.
  • Anchor rock foundation. It is the best solution for those sites where hard rock is available no deeper than 3m.
    Pile foundations is formed by three independent concrete footings of 3-4 m of diameter and 1.5 m heigh that is connected to the rock through 8-12 post-tensioned rock anchors, grouted in pre-drilled holes.
  • Gravitational foundation. For sites where rock is not available close to the surface (deeper than 10m) and consists of three independent small footings, manufactured according to the standard process of conventional wind turbine foundations.
  • Multi-pile foundations are the best solution for sites with very poor bearing capacity and are formed by three independent footings supported by several piles of 0.8m of diameter.
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Nabrabase Environmental Care

Nabrabase Elevated Foundation significantly reduces the environmental impact of the wind projects and does it by the following means. First, the concrete reduction of the foundation allows Nabrabase to save up tp 80% CO2 emissions during the installation of the wind turbines. Secondly, it just requires three independent and small footings, instead of a massive footing commonly used by the standard foundations.

DNV has defined the roadmap to certify Nabrabase as an elevated foundation with no modification in the turbine Type Certificate

The Features

CO2 Emissions Reduction

Nabrabase saves up to 80% CO2 emissions during the installation of the wind turbine.

Cost Reduction

A lighter foundation also means a most competitive foundation.

Fast Installation

The whole foundation takes just one week.

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