Durability and strength: key words for a bridge design

The new bicycle and pedestrian bridge in Uddebo, Sweden

In southern Sweden, in Uddebo, the project of a bridge is also a promise to the community. In 2024, the bicycle and pedestrian bridge over the Assman River was rebuilt to provide a durable and stable solution that would allow citizens to cross the waterway without fear of the structure collapsing. This is how a timber and steel bridge was designed to last for decades, after the collapse of the previous structure, compromised in the foundations. 

For more than two years, the local community had to rely on a temporary and impractical moveable platform.  
TBS Timber Bridge Specialists AB and Veidekke Sverige then designed a new bridge, adopting the BIFROST (Bimodulär formbar robust träbro) concept, a hybrid structure that integrates steel and timber.  

This system, which uses glulam elements and standard steel components, facilitates efficient assembly and maintenance, as the possibility of replacing modular elements if necessary is already foreseen at the bridge design stage.  

Built to last 

The new 40-meter-long and 39-ton bridge is designed to withstand extreme weather conditions and provide a service life of 80 years.  
Fasteners such as SHARP METAL, VGS EVO and HBS PLATE EVO, designed for outdoor conditions, have been used to support the structure.  

SHARP METAL hooked plates have a multitude of small hooks spread all over the surface that create a biting grip in the timber with exceptional strength and stiffness values. Made of AISI409 stainless steel, the SHARP METAL hooked plates are ideal for shear joints between timber surfaces, solid and glulam timber, CLT, LVL and timber-based panels even outdoors, stabilising the joints over time. But this is not the only perfect Rothoblaas solution to integrate into a bridge design.  

 Durability with VGS EVO screws and HBS PLATE EVO 
 

The VGS EVO, thanks to its maximum diameter and length dimensions, guarantee maximum mechanical performance for connections even outdoors. 

In fact, they are approved for structural applications subject to stresses in any direction vs the grain also for fastening aggressive woods containing tannin, and thanks to the deep thread and the high-strength steel ensure excellent tensile performance.  

VGS EVO features 20 μm multilayer C4 EVO coating with a surface treatment of epoxy resin and aluminium flakes, which showed no rust after 1440 hours of salt spray exposure testing according to ISO 9227. 

The same coating characterises the HBS PLATE EVO designed for fastening metal plates to timber in outdoor environments. They provide excellent extraction resistance and last for a long time even under harsh environmental conditions. Their anti-corrosion treatment and optimised tip offer effective and resistant pull-through. 

Thanks to solutions designed to resist, the Uddebo bicycle and pedestrian bridge project is an example of connection, not only between two banks but also between different materials. 

Construction technology here is at the service of durability, ensuring the community a safe and reliable passage for decades.  

For details of Rothoblaas fastenings and solutions suitable for exposed structures, please see the dedicated section: https://www.rothoblaas.com/products/fastening  

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