Lifting in the new foot and cycle path bridge over the B426 in Mühltal

Special geometry of the bridge requires a high degree of precision from our welders

After 10 weeks of production, the foot and cycle path bridge over the B426 in Mühltal, Hesse, was lifted into place in the night of 16 to 17 February 2024. The bridge has created a publicly accessible footpath and cycle path between Rheinstraße and the Ruckelshausen business park, which also provides access to the Riese & Müller company car park.

The biggest challenge when lifting the centre section of the bridge was to simultaneously insert the 4.5 m wide and 23 m long steel structure into six differently orientated supports with the help of two cranes during the lowering process. The two stairway sections were placed to the north and south of the bridge during the night and will be welded in place over the next few days. A total of 114 tonnes of steel were used for the bridge, including the superstructure, stairs, supports, railings and steps.

Special praise is due to the welding specialists at Donges SteelTec. They met the special welding requirements of the geometrically demanding steel bridge with great precision.

 

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International welding specialist” training course

Donges SteelTec is once again involved in training international welding specialists this year.

Darmstadt, 19.02.2024. Donges has been building steel bridges and innovative steel structures for 150 years. Each structure is unique and a small masterpiece. To ensure that the high quality requirements for steel structures can continue to be met in the future, well-trained specialists are needed. With this in mind, Donges SteelTec not only trains construction mechanics and system planners in its own company in Darmstadt, but is also involved in training courses at the Hessen Metal College in Oberursel.

Dipl.-Ing. Andreas Schade, head of quality management/assurance and welding engineer at Donges SteelTec, once again took on part of the theoretical training for the “International Welding Specialist” course at the Hessen Metal College. The practical knowledge of the course participants was deepened during an excursion to Darmstadt in the production halls of Donges SteelTec GmbH.

We congratulate the 18 participants on passing their exams and wish them every success in their future careers.

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New suspension bridge over the River Main

Sophisticated assembly concept – Donges SteelTec scores with many years of experience and expertise in bridge construction

The consortium consisting of Adam Hörnig GmbH and Donges SteelTec GmbH was commissioned by the federal motorway authority Autobahn GmbH with the replacement construction of the Main bridge near Mainflingen. Our company’s expertise and many years of experience in the field of bridge assembly was a particularly important aspect in the successful acquisition of the contract.

The old Main bridge at Mainflingen on the BAB 45 motorway is being replaced by an elegant bridge with a tensioned chord structure.

At the location of the bridge, the River Main forms the state border between Mainhausen in Hesse and Kleinostheim in Bavaria. A slender steel composite construction and the low overall height of the bridging structure ensure that the replacement structure blends harmoniously into the varied river landscape.

The two superstructures have a total length of 450 metres. The 260 m long river bridge is designed as a three-span continuous girder in pure steel construction for the main supporting girders in the longitudinal direction of the bridge and in composite steel construction for the cross girders and carriageway slab structure. The supporting structure consists of a steel trough with box-shaped longitudinal girders and is spanned by chords, which are also box-shaped. The tension chord construction allows a slender centre span of 135.00 m above the river Main with two equal side spans of 62.50 m each. The slenderness in the centre of the span is approx. L/45. The tension chords are supported by approx. 15.00 m high pylons.

The displacement of the pylon locations compared to the existing structure results in a symmetrical situation along the Main axis.

The installation specialists from Donges SteelTec face a particular challenge. Due to the one-piece cross-section of the existing bridge, it is not possible to demolish half of it. The first superstructure (RiFa Gießen) of the A45 over the Main must therefore be built in a lateral position and later shifted crosswise over a length of 450 metres. The assembly of the steel structure is just as challenging. This will be constructed at the final position above the foreland on both sides of the Main on skidways and shifted longitudinally over the Main. The approx. 500 tonne centre section is then floated in over the Main, lifted and welded.

The entire construction project will last until 2031 and is an important milestone in the redevelopment of the German bridge landscape.

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