New cycle path on the Xaver Hafner Bridge: modernization ensures safety!

New cycle path on the Xaver Hafner Bridge: modernization ensures safety!

In Straubing, the Xaver Hafner Bridge, which has served as an important traffic artery since it was built in 1985, is now fit for the future. A targeted expansion takes the increased bicycle traffic into account, and this is achieved thanks to innovative building materials and clever engineering. The reconstruction, which took place between 2022 and 2023, was necessary because the bridge, which was originally designed for motorized traffic, did not have bicycle lanes, which are, however, increasingly in demand. Another obstacle was the prestressed construction, which made a classic outward expansion impossible. The roadway moved inwards by 50 cm and was narrowed at the same time, making room for a 2.50 meter wide footpath and cycle path.

The Straubing-Bogen district office has acted with foresight. The challenge of not only adapting the bridge to today's traffic requirements, but also doing so without overloading the structure, was mastered with flying colors. Exciting technical solutions were required that ultimately relieved the load on the supporting structure. A new cornice head was made and widened from 35 cm to 50 cm to allow this one meter gain in area. This shows how important it is to sustainably modernize existing bridges and thus create a safe pedestrian and cycle path infrastructure.

Liapor lightweight concrete brings advantages

A crucial element of the conversion was the use of Liapor lightweight concrete (Type LC30/33 D1.6). Around 500 cubic meters of this material, which has 35% less weight compared to conventional concrete, were used. This innovative building material brings with it numerous advantages, not only in terms of weight savings, but also in terms of material properties. It is frost- and de-icing salt-resistant as well as corrosion-resistant.

The lightweight concrete was applied in layers of 16 to 25 cm and carefully compacted. To ensure surface slip resistance, a special broom surface treatment was used. This precise handling was necessary because the work took place at lofty heights and the utmost care was required. The renovation work was carried out by Geiger Bauwerksanierung GmbH & Co. KG from Warngau, while the lightweight concrete was delivered by Heidelberg Materials, Burglengenfeld plant.

A win for all road users

The reopening of the new cycle and sidewalk connection on the Xaver Hafner Bridge in February 2024 not only has a practical benefit, but also an important symbolic meaning. It shows that dealing with existing infrastructure can not only be about preserving it, but also about adapting it to modern requirements. The bridge is a prime example of how well thought-out engineering and innovative materials can be used to not only increase traffic safety, but also to find sustainable solutions.

With these measures, the Xaver Hafner Bridge is ready to meet the requirements of the future. This means cyclists and pedestrians can look forward to a safe crossing of the Danube, while at the same time the load on the original structure has been reduced. Here, engineers impressively demonstrate how modern techniques can adapt older bridges safely and efficiently.