Fibreglass profiles are the future of bridge construction
These were the words of Kaj Bech, when during the course of summer 2020, the company built its first complete fibreglass bridge in Sønder Felding. The request for a fibreglass bridge came from their end customer Herning Municipality, who is also planning to use more fibreglass in the future.
'It's a very simple and lightweight bridge, which allows us to get into areas that are usually hard to access by crane. We therefore need much smaller equipment. I really believe that constructions made of fibreglass profiles are the future', says Jens Andersen, foreman at Kaj Bech A/S.
According to Kim Bredgaard Grarup, case coordinator and project manager, Road, Traffic and Development, Herning Municipality, even though a wooden bridge would have cost slightly less, his decision to use fibreglass was still based on finance:
"We've got ourselves a lovely bridge for a reasonable price, so I would definitely consider fibreglass for future cycle bridges. My budget for this type of bridge is shrinking, so when we replace a bridge like this one in Sønder Felding, to me it's important that we build something that will last as long as possible," says Kim.
Herning Municipality tries complete solution in new material
The bridge is the first prototype of a new bridge concept from Fiberline, which will make building fibreglass bridges of this size much easier and cheaper. The bridge replaces an old wooden bridge over a stream near Sønder Felding school, which had over time become a safety risk, mainly for the school children crossing it.
"What attracted me to the fibreglass bridge was the fact that it would be completely maintenance-free. And at that price it became even more attractive," says Kim, Herning Municipality
"Over the years, the Municipality has been replacing existing wooden decks with bridge decks from Fiberline to make them more slip-resistant. When a bridge is close to leaves and water, it quickly becomes slippery.'
The new bridge concept consists entirely of standard profiles, which are always in stock. And standard concepts, where only the length and width need adapting, keep delivery times shorter and prices lower.
"When the price matches that of a wooden bridge, and there's less maintenance and the bridge will last longer, well then the benefits of choosing a fibreglass bridge over a wooden one are easy to see,' says Nickolai Buus Petersen, construction engineer and head of the construction department at Kaj Bech A/S.
625 kg fully assembled in the workshop
The bridge was assembled at Fiberline's own workshop under controlled conditions. And thanks to the bridge's low weight of just 625 kg, this meant a much shorter installation time on site, much to the benefit of the end customer.
"The fibreglass bridge was quick and easy to mount. It took just a couple of hours for them to finish on site. The less interruption to daily transport, wherever it is, the better,' says Kim, Herning Municipality.
The quick installation was also a clear benefit for the contractor:
"I have dealt with many different types of bridge installations over the last 20 years, some made from steel, others from concrete or wood, both new and old, and I was really impressed with both the strength and the low weight of this bridge here. Thanks to the low weight, you save a significant amount of resources during the installation process on site. Our costs are down and our time is maximised. A clear competitive parameter when compared to e.g. a steel construction,' says Jens, Kaj Bech A/S.
Looking forward to minimal or no maintenance
Compared with other traditional materials, fibreglass is a sustainable alternative as it lasts longer and incurs virtually no maintenance costs.
"The price is reasonable compared with alternative solutions. Normally you would build a bridge made of wood or steel, but a fibreglass bridge costs the same as a wooden one. Another benefit of choosing fibreglass is the minimal maintenance - and that's what the municipalities often look for. Once we have installed a bridge, the municipality prefer to be in a position to say: "Job done. No need for us to do any more," says Buus Petersen, Kaj Bech A/S.
Exceeds expectations by 8 tonnes
The bridge measures 5.5 x 2.5 metres and is built entirely out of fibreglass. As the bridge had to withstand small tractors regularly driving over it, the decision was made to further reinforce it with carbon fibre profiles. The bridge also has a slip-resistant coating and meets the applicable requirements for railings.
"That the bridge can handle up to 8 tonnes far exceeds my expectations. Most bridges that we install in cycle path areas are generally only expected to handle a load of up to 3500 kg. And we're way above that figure with this bridge,' says Jens, Kaj Bech A/S.
Blends with the landscape
Herning Municipality wanted the bridge to blend into the existing surroundings, which is why it was painted the same mahogany colour as the surrounding deciduous trees.
"People often have specific requests when it comes to the bridge's appearance - that it has to fit in with the landscape. This bridge blends in really well with the landscape here,' says Buus Petersen, Kaj Bech A/S.