North-South Limburg Connection

Designing an architectural language and identity for infrastructure interventions

With the Complex Project North-South Limburg, the Flemish government wants to find a sustainable solution for the congested Limburg connection between Hasselt (B) and Eindhoven (NL). The scope of the project is broader than a mobility study focusing on sustainable mobility and aims to improve the quality of life along the road and preserve and connect ecological landscapes and nature areas. NU architectuuratelier is developing – in close collaboration with Maat Ontwerpers – an identity and architectural language for infrastructure interventions such as tunnels (and ecopassages), walls and bridges (bicycle and car). Depending on the context, they are applied in different variants in relation to their surroundings. The overarching formal language ensures that all objects and structures are united into one coherent and recognizable project. To ensure a high visual quality, we design key infrastructure building elements that combine different material concepts (wood, concrete, earth, stone…) and structural elements (arches, deck, pillar, beam, wall…).

Enabling nature
An important aspect of this project is to use infrastructure as a kind of connecting backbone for natural areas and improve the quality of the natural environment. We design with a strong focus on serving nature to boost biodiversity. Designing for and with nature always involves an important element of unpredictability: how will nature react? The aim is not to ‘create’ nature, but to make nature possible and create optimal conditions that allow spontaneity and change.

Walls
Where the available space is too small to embed infrastructure with vegetated slopes in the landscape, we provide steep, earth-retaining structures or ‘walls’ where we prioritise nature inclusiveness and minimise the use of hard elements. We distinguish 5 types of walls; the natural living wall constructed from natural porous material to support the adjacent ecosystem as a habitat for fauna and flora; the mineral living wall in the more urban context where a gabion wall is filled with stone filler that can host insects, flora and other fauna; the dune wall with vertical sand walls specifically deployed in segment North near Diest and refers to the historical dune landscape that was once here; the acoustic wall that absorbs sound with a high image quality through the use of sustainable materials with a natural and tactile character and which also looks at how pollution from exhaust fumes can be absorbed and the village wall specifically deployed in village centres.

Tunnels
Two long tunnels are being built under the centers of Houthalen and Helchteren for the N74. The architectural design of the tunnel mouths enhances the landscape character as much as possible with natural slopes or with an acoustic wall topped off with a mineral living wall.
We also design ecological passages to reconnect valuable landscapes and biotopes. To allow the profile of the stream to continue as naturally as possible under the infrastructure, we do not provide a floor slab, while gratings in the upper road surface provide daylight and widening tunnel mouths guide fauna inside.

Pillars
Pillars – essential in a bridge structure – play an important role in expressing the character of the bridges. In the design, we foresee three types: the slender steel column, which minimizes the visual and physical impact on nature and is therefore suitable for sensitive natural areas; the concrete ellipse, which combines elegance with structural advantages; and the concrete vault, which possesses both structural and spatial qualities and shapes the spatial experience between different speeds (cyclists versus heavy traffic).

Bridges
Bridges are very present and define the landscape image, making them important elements to strengthen the identity of the North-South link. We envisage 3 types of bridges; wooden bicycle bridges that focus on an attractive and refined infrastructure for the bicycle (experience), larger concrete scale bridges that establish a specific relationship with the context or mark a spot and concrete road bridges that cross the motorway or the N74 and are recognizable from the car as recurring elements.

For the cycle bridges, the fundamental choice is made to materialize them in wood, not only because of its warm, tactile and sustainable character, but also as a way of actively contributing to reducing CO2 emissions and increasing CO2 storage. Depending on the span and context, the supporting structure is provided in the bridge deck itself or in a solid railing as a supporting beam. By providing it in the bridge deck itself, the bridge becomes very light and open which creates a scenic experience for the cyclist. If the supporting structure is in the solid railing, the bridge becomes more closed and screens the cyclist from the busy traffic below.

The concrete shell bridge acts subservient to the context and has a subtle visual presence with a fine concrete edge that carries the overlying land or road surface. We distinguish two types that either bet on the transverse landscape; where the landscape runs over the construction or on the connecting landscape; where the landscape runs under the construction. In both cases, we seek synergy with the ecological landscape around and use living walls where possible.

The concrete road bridges that crosses main roads also aim for a slender silhouette through the smart use of concrete, making them appear understated in the road landscape.

client De Werkvennootschap, Departement Omgeving, Departement Pattyn
location Limburg
date 2022 - heden
status Bouwaanvraag ingediend
icw STUDIO NZL: IMDC (Tractebel), Arcadis, MAAT Ontwerpers, 51N4E, NU Architectuuratelier
engineering office Arcadis, IB-Miebach