Smart Circular Bridge for a circular built environment

Project Summary


Today’s material use in construction industry

The construction industry needs to make a shift in material use. However, reliable alternative solutions for improving material efficiency and natural resource use are lacking. Dutch municipalities maintain over 12.000 pedestrian and cyclist bridges. 41% are in a poor to very bad shape. Germany shows similar figures. Within the NWE territory 0.5 % replacement per year of just these bridges, equals to 95.000 tons per year of primary raw material use.

The EU strategy towards sustainable materials

The EU's action plan Bio-Economy Strategy [EC. 2018] stresses the need for a shift towards natural materials. Despite an increasing market demand, construction industry remains hesitant to implement new natural material applications, because their material properties, especially time-related degradation properties, are insufficiently known to fully guarantee safe use, for a sufficient long time.

Modern research offers new opportunities

Sensor technology combined with smart computer algorithms make it feasible to equip structural components with sensors and follow their behaviour. This is known as Structural Health Monitoring. Material behaviour is evaluated in real time. A smart sensor system evaluates sensor input and generates early warnings, before critical levels of material degradation are reached. It enables real time maintenance or replacement of components. In Smart Circular Bridge the unknown aspects of material-ageing are counterbalanced by the Structural Health Monitoring system. Structural safety can thus be guaranteed. This approach will significantly accelerate resource efficiency in infrastructure.


Our contribution to a sustainable construction industry

Smart Circular Bridge will build and equip two demo-bridges in the Netherlands and Germany and one final bridge in the Netherlands.This can reduce up to 677.000 tons of raw fossil material every year in the EU. Using the “Reduce, Reuse and Recycle” principles, Smart Circular Bridge will actively promote the role-out in industry thus accelerating resource efficiency throughout the EU.

Project Partners

Lead partner

Organisation Address Email Website
TU/e Technische Universiteit Eindhoven 2 De Rondom
Name Contact Name Email Country
KU Leuven Aart Willem van Vuure Belgium
FiberCore Europe BV Ed Hoogstad Netherlands
24SEA BVBA Gert de Sitter Belgium
Com&Sens Geert Luyckx Belgium
FibR GmbH Julian Fial Germany
Van Hattum en Blankevoort BV Sipke Huitema Netherlands
Lineo - groupe NatUp fibres (Before Ecotechnilin) Gwenn Prevost France
Universität Stuttgart Hanaa Dahy Germany
Materialen & Energie Transitie MNEXT (stichting Avans Hogeschool) Maurice van Londen Netherlands
Vrije Universiteit Brussel Christof Devriendt Belgium
Gemeente Bergen Op Zoom Dietmar Lemmens Netherlands
Gemeente Almere Daria Abolina Netherlands
Stadt Ulm Tobias Knöpfle Germany
Proesler Kommunikation Martin Prösler Germany

Climate protection and circular economy are becoming increasingly important in the construction industry. As part of an EU project, three pedestrian and bicycle bridges in Germany and the Netherlands are currently being planned and build. The so-called "Smart Circular Bridges" (SCB) are made of bio-composites.
A sophisticated monitoring system continuously monitors the stability and material condition. The data are automatically analyzed by the system and shared in real time. This ensures not only the highest level of safety for use, but also provides extensive information for planning further bridges. The project uses renewable resources in an innovative way. Beyond bridge construction, it demonstrates the potential of a climate-friendly bio-economy in the construction industry.

Meeting the challenges – a contribution to circular economy

Construction industry needs to make a shift away from its extensive fossil materials use in order to achieve a circular economy. To meet the ambitions resulting from the Paris Climate agreement, it is essential to significantly increase the use of circular materials. By using fast growing plants, like flax and hemp, CO2 is bound in one year of growth and only given back to the atmosphere after its years of use, thus reducing the effect on Global Warming. Bio-based materials are not per definition bio-degradable. Smart Circular Bridge implements research and innovations aiming at closing all material cycles.

Circular economy in practice

Bio-composites provide the basis for three bridges realised and built by the year 2023.


Bio-composite material

Just like conventional composites, a bio-composite is a combination of fibres and resin. In a bio-composite the natural fibres, mainly provide the strength, the bio-resin glues these fibres together. By creating this new material the bio-composite offers a lot of form freedom.  It becomes possible to design structurally optimised as well as resource-efficient designs. The material and its fibres can be optimized and used exactly in the places where they are most effective.

from flaxflower to biocomposite


Structural Health Monitoring – smart and safe

With conventional materials, like for example concrete, there is a long history of trial and error, giving us experience on what design is needed for long life and safe use. For these new materials Smart Circular Bridge introduces a new approach to structural safety, by using a “self-sensing” system. This so-called Structural Health Monitoring (SHM) system constantly monitors the structure and its material behaviour, but it also evaluates its level of structural safety. It uses innovative and sensitive fiber optic sensors (FBGs). Real-time data is constantly collected and evaluated. This makes it possible to give off early warnings in case preset material-limits should be reached. To ensure a full safe structure, the in situ data of the Smart Circular Bridge is compared with results of accelerated material degradation tests in the project. The material limits are set sufficiently low and safe, in close collaboration with approving authorities.

At the same time, engineers can refine their calculation and material models with this data. On this basis, they will further develop materials and design models for the next bridges and many other applications. Currently, teams are already researching columns and façade elements. Rotor blades from wind turbines are also conceivable.


Structural design and load bearing properties

The specific mechanical properties of different bio-composites can vary greatly. Design and material selection is calibrated and carried out in accordance with specific material test results on strength and stiffness. The resins are bio-polymers that in combination with the natural fibres provide great strength. The used bio-composite materials in the Smart Circular bridges have a strength of about half the strength of aluminium, but the combination of this strength with its lightweight properties give bio-composites great potential for application in building and civil structures.


sketch of different design options for the SCB
another sketch for design


 Options for efficient and elegant designs

Design options are characterised by architectural design and structural efficiency. Key elements are structural safety, aesthetical quality, functionality as well as feasibility, production and cost effectiveness. Our Smart Circular Bridge project aims to integrate all these requirements in its optimized designs. It will show its potential by realising three demo-projects of Smart Circular Bridges in Germany and the Netherlands and by sharing its results over the NWE Interreg region and beyond.

Another innovation in the project is the bridge railing: this component is also made of a bio-composite. It is produced robotically using a coreless winding technique. The resulting triangularly cross-linked natural fibre bundles made of flax are connected to the main grider of the bridge on both sides via cantilevered transverse stiffeners. This emphasises the lightness and delicacy of the design and underlines the aesthetic and technical possibilites of bio-composites and natural fibres.


Production Process

For fiber reinforcement plastic (polymer) composites, the general fabrication process follows three main steps:

  1. Arrangement (orientation and configuration) of the reinforcement using an internal or external shape or mold.
  2. Combining or infusing the reinforcement with the resin to a composite system
  3. Curing of the composite material.

Smart Circular Bridge uses a vacuum-infusion method combined with internal foam shapes and external moulds. In the previous experimental bridge at the TU/e campus, a bio-degradable foam PLA was used in the core, acting as a lost mould thus realising the changing shape over the length of the bridge.

The bridge was produced as a complete element in a vacuum infusion process. In the first step, a negative mould of the bridge element was laid out with mats of flax fibres. On top of this, blocks of polyurethane foam (35 kg/m3) covered with flax mats were positioned close together. The entire package was wrapped again with flax mats and with a vacuum bag. After the air has been extracted, the resulting vacuum ensures that the polymer can flow in in a controlled manner and fill all the cavities. In the course of this infusion process, all the blocks are force-fitted together. The polymer takes about one day to cure. This completes the entire element.


For circular building and infrastructure in NWE countries, it is essential to optimise the (re)use of material and natural resources in construction industry. Within Smart Circular Bridge project, the aim is to achieve complete insight over the environmental impact of the bridge by using a LCA (Life Cycle Assessment) methodology. This will focus on the material selection, production phase, use phase and end of life scenarios in which the recovery of the materials is studied. By using the Smart Monitoring tools, the goals is to further elongate the service life of Smart Circular Bridge, which will result in lower environmental impacts per year.


Innovative new materials: flax and bio-resin

Apart from the 100% natural flax fibers, the resin will also come from non-fossil sources as much as possible. The proportion of bio-resin is 25% for the first bridge, but it will reach 60% or more for the next bridges. This is achieved by using waste products from bio-diesel production and recycled PET bottles.

“These materials have a great future. In particular, the intensive cooperation between science, industry, and communities has given a big push to materials development."

Professor Rijk Blok | TU Eindhoven


Accelerating materials research with AI

As bio-composites offer great opportunities, research on the materials is continuously ongoing. This is why the bridges are systematically monitored in real time. Roughly 100 sensors in the bridge provide data on the material's behaviour in everyday use. How does the structure behave when 200 people walk over it at the same time? What happens in different seasons, during storms, hail, and snow? How does the ageing process of the material take place?

"The current results make us optimistic: we expect to build bridges with significantly larger spans and higher loads in the future."

Professor Dr. Patrick Teuffel | TU Eindhoven


Designing today for the end of life

With the circular economy in mind, the project is investigating which options are open for the building material after the bridges have reached the end of their life after many decades. Currently, three possibilities are conceivable: mechanical, chemical, and even biological recycling with fungi. It is important that the material's usage cascade lasts as long as possible. To achieve this, the end-of-life options are to be taken into account when designing the bridge.

Interdisciplinary teams drive development

The first "Smart Circular Bridge" with a span of 15 metres has been realised  using around 3.2 tonnes of flax fibres . The project team consists of five universities, seven innovative companies, and three municipalities. The first bridge set up at the Floriade international horticulture exhibition in Almere, Netherlands was opened on April 22nd 2022.

The bridge structure consists of the deck and a railing made of bio-composites as well as abutments with approach ramps. A multi-cell, rectangular box with continuous longitudinal webs forms the bridge deck. A transverse web terminates each end. The width of the hollow box is 3 metres, the height 90 centimetres and the span is 15 metres. The thickness of the box panels varies from 15 millimetres for the longitudinal webs to 20 millimetres for the soffit and 25 millimetres for the carriage surface. The static calculation by the Eindhoven University of Technology shows that these dimensions can carry the required loads – i.e. the permanent loads from the structure and the surface, the areal traffic load as well as a vehicle load with 2 x 25 kN axle.

The abutment construction consists of a sheet pile wall construction, two bored piles and a steel beam that connects the bored piles and serves as a support for the bridge. The vertical support reactions from the bridge are transferred to the bored piles via the steel beam. Horizontal support reactions in the longitudinal and transverse directions are introduced into the sheet piles. As an access route, concrete drag slabs are placed on a sand bed between the sheet pile walls on both abutment sides.

A public dashboard with monitoring data

A Structural Health monitoring system with optical glass fibre sensors in the bridge provide information on material strains, and acceleration sensors detect even the finest vibrations caused by wind. Evaluation of data from the sensors is carried out with the help of artificial intelligence (AI) to recognise patterns in material behaviour. The data can be viewed on a dashboard on a public website (

Structural Health Monitoring: interesting findings and conclusions after 8 months

The Smart Circular Bridge in Almere has an elaborated Structural Health Monitoring System. Maximillian Weil from Vrije Universiteit Brussel talks about the reasons behind such an elaborate system, interesting findings and the conclusion after 8 months of monitoring the Smart Circular Bridge in Almere.

By looking at the messured data, it was found out that even during unintended usage, such as when a transporter crossed the bridge, the bridge remained stable and safe. If you want to have a look at the SHM data yourself, you can do so via the publicly available dashboard ( or simply click on the QR code in the video.

Structural Health Monitoring: in-depth analysis

Maximillian Weil from the Vrije Universiteit Brussel highlights important aspects of the SHM and explains the data analysis.

 The Rijk Blok Bridge in Almere

After the Floriade expo 2022 in Almere closed, the site will be converted into the city district of the future in the coming years. The Smart Circular Bridge continues to be part of this new living environment and has since November 25, 2022 been named after Rijk Blok, who passed away completely unexpectedly on May 7, 2022.

Rijk was the project leader of the Smart Circular Bridge project. The photo shows Rijks' wife and his son at the Smart Circular Bridge in Almere, Netherlands.




This Smart Circular Bridge is realized in the middle of the old town in Ulm. It is a comparatively small bridge with dimensions of about 7 by 5 meters. It leads across the Blau River to a small island where a playground is located.
As in Almere, this bridge will be built as a biocomposite bridge with flax fibers and bio-resin. The proportion of bio-resin is increased to around 60%. For comparison, the proportion of bio-resin in Almere was 25%. The bridge will be built with a railing made of flax, which will be produced by robots using the coreless winding technique.

A different cross-section of the deck was designed for this bridge, which needs less material. It consists of a top plate supported by ribs instead of a sandwich. This is possible because the span of the Bridge in Ulm is less than the span of the Almere Bridge and proofs, that multiple structural solutions are constructible and feasible. The service vehicle that needs to be taken into account for the Ulm deck is larger than 2 x 25 kN. For Ulm, we take into account a maintenance vehicle with a rear axle load of 71 kN and a front axle load of 50 kN.

Structural health monitoring will also be improved. Faster response times and more efficient sensors in the bridge with an optimized layout that matches the new design in Ulm.


Building mayor Tim von Winning talks about the Smart Circular Bridge in Ulm

One of the ways to reduce the immense CO2 emissions in the construction sector is the Smart Circular Bridge project. Tim von Winning, mayor of the department city development, building and environment in Ulm, has agreed to the construction of a biocomposite based bridge in his city and expects important learning effects from the Smart Circular Bridge project in regard to the many bridges that will be built in the future.

The opening of the Ulm Bridge is yet to be scheduled.


An old material is being rediscovered: flax has been with us for thousands of years in the form of clothing, sacks or robust ship's ropes. Now the plant fibres are experiencing a renaissance and could become the building material of the future. Combined with a special bio-resin, it can be made into a light and highly stable material with properties comparable to aluminium or light steel. The EU project "Smart Circular Bridge" shows what is already possible with this innovative new material: three bridges are made of this so-called bio-composite. A first one has now been realized in Almere, Netherlands, and two more will follow.

General Information

The first "Smart Circular Bridge" with a span of 15 metres has now been realised at the Floriade, international horticulture exhibition in Almere, Netherlands. It was opened on April 22nd 2022.

General Video Dutch

General Video German

General Video French

Biocomposite Materials

“Biocomposites are making a big jump in the sustainable architecture of tomorrow”, says Hanaa Dahy, junior professor at the Universität Stuttgart and project partner of the Interreg North West Europe (NWE) Project Smart Circular Bridge. In our video interview, the junior professor for biomaterials and materials cycles in architecture reveals her personal motivation for taking part in Smart Circular Bridge and provides exciting insights into biocomposite materials.

Flax fibres are a promising material

Karim Behlouli, Managing Director Eco-Technilin, talks about flax fibres and its benefits for composites.

Flax fibre composites offer a sustainable and versatile solution for modern lightweight building products. With reduced environmental impact, remarkable strength and durability, flax fibre composites are also an attractive choice for infrastructure projects, such as the Smart Circular Bridge.

The Structural Health Monitoring System

A Structural Health monitoring system with optical glass fibre sensors within the Smart Circular Bridge provides information on material strains, and acceleration sensors detect even the finest vibrations caused by wind - in real time. In this in depth interview with Eli Voet and Christof DeVriendt from the University of Brussels we talk about the integration, the functionality and the goals of the bridge management system.

A talk with Martijn Veltkamp of FiberCore Europe

FiberCore Europe is one of the 15 partners in the “Smart Circular Bridge”-project. The company from the Netherlands has a lot of experience with fiber reinforced polymer bridges. They have built around 1.000 Bridges so far. Martijn Veltkamp, a concept engineer at FiberCore Europe, talks about the added value of bio-composites in bridges, the design process and the future role of bio-composites in the construction industry.

A talk with Grégoire Beauduin of Com&Sens

Com&Sens is one of the 15 partners in the “Smart Circular Bridge”-project. The company from Belgium implements fiber optic sensing concepts for condition based health monitoring of concrete, steel or composites structures based on fibers. Business Developer Grégoire Beauduin talks in depth about the core business of Com&Sens and how the bridge management system helps to understand the material behavior in time.


Bio-composites: A high performance material

Prof. Aart Willem Van Vuure, University of Leuven, on why considering bio-composites as a building material is a viable option for infrastructure. Take a look and find out why bio-composites have similar properties to wood.

Press Releases and other media


We are happy to provide comprehensive press material via our media contact:

Proesler Kommunikation GmbH
Karlstraße 2
72072 Tübingen - Germany
Phone:  +49 707123416
Mail: Mr. Aleksander Manko (


Press releases:





 Project Flyer:

  • For a circular built environment                                                                                        (english / pdf)
  • Neue Werkstoffe für den Brückenbau                                                                               (german / pdf)  


Additional or more detailed information to "The Smart Circular Bridge":

Bio-Based Composite Footbridge Design, Production and In Situ Monitoring

Bio-Composieten: Ontwerpen et vezels en ‘bio’ polymeren (dutch)

Upcoming events


  • Opening event Smart Circular Bridge Ulm - more information soon.


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The innovative bridges are created in the context of the Bio-Economy Strategy of the European Union and are supported by the Interreg North-West Europe Programme. The project is led by the Eindhoven University of Technology, which is working with a total of 14 partners from science, industry and local authorities to complete three bridges at the locations Almere (NL), Ulm (DE) and Bergen Op Zoom (NL) by 2023.


TU/e Eindhoven, University of Technology

TU/e is a prominent University in the Netherlands, with high ranked national and international research and education and a strong commitment to connecting and bringing research and technology innovations to market with a strong network. The Chair Innovative Structural Design has achieved advances in research and design regarding resource efficient structures. It was leader in the 4TU project Biobased Bidge, realized in 2016 and since then followed up with ongoing research in this field.
Link to the website:

KU Leuven

The Composite Materials Group of the Department of Materials Engineering of KU Leuven has about 35 years of experience in research on many aspects of composites technology, from processing to testing and analysing composite materials. Since the late nineties one of the focal points has been natural fibre composites, with the aim to develop more sustainable, environmentally friendly composites. Research on natural fibre composites target the weaker or less developed aspects regarding durability.
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FiberCore Europe

For the past 10 years FiberCore Europe has put FRP as a construction material on the map. With the construction of more than 1000 bridges worldwide, many of them in the Netherlands, the prefab FRP bridge has become a common sight in everyday scenery. Using the unique InfraCore® technology, FiberCore Europe builds bridges and locks gates with an eye to the future: lightweight, robust, sturdy and durable. With our own factory in Rotterdam and our team of skilled engineers and constructors, we build bridges that require hardly any maintenance and will last for more than 100 years. And that does not have to be in one location; the bridges can easily be removed and replaced.
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24SEA is the leading independent structural monitoring partner on the Belgium market of Offshore Wind and Marine Renewables. 24SEA offers testing services and develops dedicated short and long-term structural health monitoring systems for offshore structures. Their in-house developed data analysis tools provide the operator with the insights that are crucial to minimize construction and installation costs and reduce their operation, maintenance and inspection costs.
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FibR is a construction company realizing architectural fiber composite structures for load bearing structures, facades, and interiors. The computational design methods and robotic fabrication facilities enable the exploration of a novel design and construction repertoire for resource efficient architectural construction. The interdisciplinary team offers vertically integrated digital construction services across all project phases ranging from concept development, design assist and building component certification to robotic production and on site installation.
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Com&Sens has a long track record of embedding optical fibre sensors in composite structures. In this project, Com&Sens will focus in close cooperation with 24Sea on developing and further improving a method to robustly embed the sensors into the bio-bridge. For the project it is essential to capture the strains and temperature with high accuracy. The optical fibre brag sensors can do so, provided the embedding is of high quality.
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VanHattum en Blankevoort

The core business of VanHattum en Blankevoort is to design, construct and maintain infrastructure and civil projects (e.g. bridges, viaducts, quay walls, locks, water treatment plants etc.) in the Netherlands, since 1831. The main focus of VanHattum en Blankevoort lies on project management and design. It has a clear focus on sustainability and innovation. It has recently constructed a circular viaduct in 2018. Van Hattum & Blankevoort are operating companies of Royal VolkerWessels Stevin NV.
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Lineo - groupe NatUp fibres

Lineo - groupe NatUp fibres is a leading provider of natural fibre solutions. It has production sites in France and the United Kingdom. It is a French Norman company specialized in the manufacture of reinforcements based on natural fibres. It manufactures non-woven felts, devoted to the automotive industry, as well as a range of woven fabrics (Lineo range) and non-woven dry or pre-impregnated for composite applications, dedicated to many different fields from sports to furniture or transport.
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University of Stuttgart

The University of Stuttgart is a leading technically oriented university with global significance. They progress interdisciplinary integration of engineering. The ITKE BIOMAT institute: is famous for investigating and realizing cutting edge structures, i.g. the 2018 experimental biobased pavilion. One of its main goals is to raise and translate ecological concerns in newly developed sustainable smart materials and integrating the architectural and user perspective.
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Energy and Material Transition MNEXT (former: Centre of Expertise Biobased Economy (Avans University of Applied Sciences)

Materialen & Energie Transitie (MNEXT, formerly known as Centre of Expertise Bio Based Economy CoEBBE) of (Avans University of Applied Science with circa 28.000 students) is a research center that stimulates research and knowledge valorization through public-private collaboration stimulating biobased material applications. For this the MNEXT researchers work alongside entrepreneurs in research projects with direct spin-off to education.
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Vrije Universiteit Brussels

Vrije Universiteit Brussel has a strong commitment to valorization and successful innovations by well-established relations to industry as well as international research networks. The department of mechanical engineering and acoustics and vibration research group has key expertise in Structural Health Monitoring and data handling, for example on reliability analysis of fatigue damage extrapolations of wind turbines using offshore strain measurements. This expertise will be directed to SCB.
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City of Bergen op Zoom

Bergen op Zoom is a Dutch municipality. Besides all its other tasks and responsibilities, the city owns and maintains many bridges in different sizes and materials. Bergen op Zoom is part of the Biobased Delta in which it co-organizes initiatives on improving sustainability and circularity through the use of bio-based materials. It has already realized bio-based public stairs within its city and it also has collaborated in the realization of a bio-based cladding of an ecoduct: Zoomland viaduct.
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City of Almere

Almere is a municipality with many activities and initiatives around circular and sustainable economy, clean energy and transportation, circular urban developments and with many cradle to cradle approaches in material use and waste treatment. Together with the province of Flevoland it organizes the Floriade 2022, the 7 th world Horticulture Expo with the theme "Growing Green Cities". This Floriade is a living lab which provides an excellent platform for the first SCB investments.
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City of Ulm

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Proesler Kommunikation

Proesler Kommunikation is a PR agency with conceptual strength and specialist expertise. They have a sound knowledge of the construction industry, future technologies and sustainable management. As an external press office or supplier for individual projects, tailored PR strategies and communication concepts are created. Strength is the provision of strategic advice to companies/projects and the implementation of successful PR concepts in their relevant target groups and markets.
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