PARADIS BRIDGE

The case is taken from: Samferdsel & Infrastruktur 02. utgave 2024

Paradis G/S-bridge will be the longest of its kind in the world. It is a bridge made of fiber-reinforced plastic (FRP), or composite in Norwegian, consisting of fiberglass and carbon fiber. Using these materials is relatively new to the public road network in Norway. They have not been used except for factory production and placement, and they require minimal maintenance.

The bridge will improve the situation for pedestrians and cyclists and increase traffic safety at the crossing point of the road and light rail. The project, along with other efforts in the Paradis project, will ensure universally designed future streets and increase environmentally friendly measures.

Vestland County Municipality, along with consulting firm A4 and FiReCo, is involved in the project. The main contractor is Consto, with production by CSUB. Meanwhile, transportation is handled by Royal Transport.

The bridge is now being produced at CSUB in Arendal, at the factory in Eydehavn. It is 7 meters wide and 42 meters long. The entire bridge will be transported to Paradis and lifted into place. All details around this are not yet finalized, but installation is scheduled for August with opening in September 2024.

The contract is a turnkey contract with collaboration.

BUILDING AN INNOVATIVE COMPOSITE BRIDGE IN BERGEN

Paradis bridge is under construction over County Road 582 in Paradis, Bergen. The bridge is 7.1 meters wide and 42.5 meters long and is being built with fiber-reinforced polymers (FRP), or fiber-reinforced polymer composite in Norwegian.

Vestland County Municipality and contractor Consto have now started the production of Paradis G/S-bridge at the manufacturer CSUB in Arendal. The bridge will later be transported and installed over the county road.

The project is part of the Environmental Lift in Bergen and aims to improve the situation for pedestrians and cyclists, as well as increase traffic safety at the crossing point of the road and light rail. The bridge will also be universally designed for pedestrian and bicycle paths.

The project received support from the Norwegian Public Roads Administration in 2015 for this work to Vestland County.

Now, the bridge is in full production at CSUB in Arendal, and a very complex object is beginning to take shape. Already today, the construction fills the entire factory. The project has taken shape due to the lack of regulations for composites, defining the bridge as a pilot project. In such production processes, we generally have only one chance to get it right. Additionally, the large structures mean that health and safety at the factory become particularly important, says Tryti Nilsen.

Projected the entire area

Multiconsult has assisted from the start of the project in 2015 with both regulatory work and detailed design across all disciplines for the Paradis Infrastructure project.

The most visible part, and the crown jewel, will be the composite bridge, but Multiconsult has also assisted as advisors and project managers on other parts of the project. This includes upgrading pedestrian and bicycle bridges from Stranistain Michelingens road to Turveyn, establishing foundations for new tram lines between Turveyn and Jacop, updating and excavating water and sewage, over water and sewage pipes, and preparations for further expansion of Paradis. Additionally, we have worked throughout the area for social jobs, including Allmenningen, and designed various safety structures. For the composite bridge, we have designed the substructure, landscape, and handling of the bridges, as well as the final assembly infrastructure as construction advisors. Stian Persen, advisor at Multiconsult.

The project is an initiative for increased and nodal development, with improved traffic safety for a greener future. The project is part of many interfaces and development plans, and construction is underway. Due to the project’s complex boundary relations, infrastructure, and the regional plan from 01.10.2020, the project has had some starts and stops. This has made it particularly challenging to ensure continuous and good holistic solutions. It is also challenging to ensure a safe school route through the construction area, with simultaneous construction of infrastructure and private development. Thanks to skilled and collaborative professionals and project managers from all parties, we are left with a project we can be proud of.

«I was lucky to have worked on the development of Paradis G/S-bridge since the start of the project at the Norwegian Public Roads Administration in 2015 and followed the bridge to completion. Due to the challenges with the underlying and light rail and high-traffic road, several alternative bridge solutions and materials were considered early on. Due to the material’s low weight, high strength, and maintenance-free properties, it was early decided to go for fiber-reinforced polymer composite, or synthetic material as it is called in handbook N400.

«At that time, a bridge had never been built with such material according to the Norwegian Public Roads Administration’s handbooks, so the whole process and use of the material have been a developing, educational, and innovative process for all parties. This is entirely in line with the UN’s Sustainable Development Goals, and the bridge has opened up innovation in material use in an otherwise conservative transport sector. It is always challenging to be the first, but the benefits are reaped in the form of new opportunities and more sustainable infrastructure with lower greenhouse gas emissions than more traditional bridge materials,» says Persson.

Calculating the properties of the composite structure

FiReCo, advisor on the project, has provided engineering services in construction and analysis of composite structures since 1991.

«We were involved in designing a pedestrian bridge in composite in Fredrikstad, almost 60 meters long, as early as 2003. It is still one of Europe’s longest movable composite bridges. We were very early with this type of bridge construction,» says Alf Egil Jensen, composite advisor at the company.

The company has close contact with institutions such as DNVGL, FFI, SINTEF, KIWA, HIØ, UiO, and NTNU in Norway, as well as other well-known foreign institutions.

«When you look at this project, there was a finished design proposal in the tender documents. We were not involved in the early phase but joined, together with CSUB, after it was put out to tender. We applied for the assignment together but saw that we could not build the bridge with the design proposal that was present and came up with an alternative where we cast larger parts to have fewer joints. Experiences with wooden bridges, where joints are made with both rigid and soft materials, show that it creates more challenges.

«In the original design proposal, ready-made metal profiles were also used, which were filled with composite. We quickly saw that this became too complicated and did not fit well with CSUB’s production. We therefore adapted the design to their production method. Instead of classic steel trusses, where rods are bolted or welded together, we make a large mold where we cast the bearing truss on the sides in one piece.

NO TRUSS BRIDGE HAS EVER BEEN BUILT IN COMPOSITE IN THIS WAY, AND WE HAVE THEREFORE HAD TO DEVELOP A NEW PRODUCTION METHOD FOR THIS PROJECT.
– Jon Inge Brattebakk

«We use a textile, a reinforcement fabric, consisting of fibers that are knitted together. Depending on the load distribution on the bridge, laminates of knitted mats with reinforcing fibers are built up layer by layer. We then place a vacuum cloth around the package and inject resin, polymer, which acts as glue. In the end, you are left with a rigid laminate that meets the requirements in the strength model. There is a large element of customization in such processes. We therefore work closely with CSUB and perform advanced analyses to build the strength model. It is partly about the properties of the materials and achieving sufficient properties on the bridge,» he says.

Calling for standards and manuals

Jensen says that in this project, they have followed a Dutch standard and DNV’s standard C501 Composite Components along with handbook N400.

«Composite is not well covered by manuals and standards, but a new Eurocode standard addressing composite is coming in 2026. In that sense, this is pioneering work since standards are not fully adapted. We have therefore undergone a long third-party process with the Norwegian Public Roads Administration to get permission to build in this way. Now we are well into production and should be finished at the beginning of July.

«The advantages of composite are that the material is virtually maintenance-free. When the bridge is fully cast and assembled, it will stand for 100 years without maintenance. This provides significant environmental benefits throughout the bridge’s lifespan,» says Jensen.

THE ADVANTAGES OF COMPOSITE ARE THAT THE MATERIAL IS VIRTUALLY MAINTENANCE-FREE. WHEN THE BRIDGE IS FULLY CAST AND ASSEMBLED, IT WILL STAND FOR 100 YEARS WITHOUT MAINTENANCE. THIS PROVIDES SIGNIFICANT ENVIRONMENTAL BENEFITS THROUGHOUT THE BRIDGE’S LIFESPAN.
– Alf Egil Jensen

Well into production

Jon Inge Brattebakk, Market & Technology Manager at CSUB, talks about an exciting project.

«We built a pedestrian bridge in Fredrikstad in 2003, which was then one of the most advanced composite bridges built. We know that the method using vacuum injection is well known for projects and large structures. We have also made numerous subsea bridges for the oil and gas industry and pedestrian bridges for fish farms.

– No truss bridge has ever been built in composite in this way, and we have therefor had to develop a new production method for this project. Earlier composite bridges are assembled in the same way as wooden modules with nodes in other materials. We did not want that and instead developed a new solution where we integrate the nodes of composite and cast them together with the entire beam. That is the new thing in this project.

– Now we are in the process of casting components and will start assembly in early August,» says Brattebakk.

Many challenges for the contractor

Øystein Mehl Eide, General Manager at Consto Anlegg Vest, says they were early to express interest when the project was put out on Doffin.

«The tender request quickly showed us that we were dealing with a particularly challenging project. At the same time, Vestland County Municipality is a very important customer for us, a knowledgeable, innovative customer with many skilled people. When the contract form also included collaboration, we knew this could be an exciting project for us. We talked to FiReCo after the conference, and through mutual acquaintances and references, Consto, FiReCo, and CSUB agreed to collaborate on submitting a bid for Paradis bridge.

«In the spring of 2022, we signed the collaboration agreement and held a successful kickoff meeting with the client and the client’s advisors. The next few months were used to develop and improve the solution proposal before submitting it to the Norwegian Public Roads Administration for approval. A prompt approval proved challenging, but we have managed to maintain focus on the product together with the customer and advisors, and in the end, we received approval for a completely unique bridge in early 2024.

«Since then, it has mostly been about production and preparing for transport. The other major X-factor in this project, after the construction material – composite, is to manage to transport and assemble a 42.5-meter-long bridge in one piece. Here, Royal Transport AS has been an invaluable contributor, and both we and everyone involved in the project are tremendously excited to see this large bridge being lifted from the shipping line in Bergen and up to Paradis junction. It will be quite a sight.

«What challenges or surprises have arisen along the way?

«Since this is pioneering work, it has been challenging to get a good flow in the project. The approval process, as mentioned, has taken a lot of time, and I commend Vestland County Municipality for showing patience, taking social responsibility, and leading with innovative solutions. We have a good distribution of work and responsibility, and collaborative projects are new for both our and their organization. The experience with this form of collaboration is also one of the biggest surprises so far, and in a positive sense,» concludes Mehl Eide.