Successful pylon installation on the Steigerwald motorway

Another milestone was reached on the A3 Steigerwald motorway last Wednesday: the pylons of the BW314a structure were successfully moved into position by the Donges installation team. This bridge is the twenty-first of a total of 22 planned steel structures and the first cable-stayed bridge in the project.

The pylons are technically challenging as they are inclined in two directions when viewed from above. The cross-section tapers towards the top. The pylons were assembled using two mobile cranes. Thanks to a hinged construction, the mobile cranes were then able to erect the pylons safely and precisely. There was a critical tilting moment during which the pylon swung through on the crane hook. This method made it possible to bring the pylon into a vertical position in a controlled manner and at the same time anchor it to the intended attachment points.

The bridge was planned almost exclusively with the help of 3-dimensional models, which made the construction and assembly planning much more precise.

In terms of steel construction, the BW314a structure is probably the most beautiful and challenging bridge on the Steigerwald motorway. As a cable-stayed bridge, it will attract attention above all through its architectural aesthetics.

With the successful erection of the pylons, the major project is nearing completion, at least as far as the steel construction is concerned.

The A3 Steigerwald motorway is a major infrastructure project that is of great importance for both local and national traffic.The expansion and modernisation of the route is expected to significantly improve road safety and traffic flow.

The client and the companies involved can look back with pride on the work carried out so far, which has paved the way for a modern and efficient transport artery through the Steigerwald.

Bar arch bridge for the western regional bypass in Frankfurt lifted into place with great precision.

Darmstadt, 03.06.2024. In a spectacular operation, the 1300-tonne tied-arch bridge with a span of 113 metres was installed in its final position over the railway tracks of the Frankfurt-Mannheim line at the Waldstadion in Frankfurt am Main on Friday. This makes the future route of the Regional Tangent West (RTW) clearly visible for the first time: its light rail vehicles are scheduled to run over the bridge from 2028.

The Donges SteelTec assembly team began preparations for the final assembly of the bridge on Wednesday. In order to hoist the steel colossus into position, it was first stored on two huge mobile platforms (SPMT) in the days leading up to its installation. The self-propelled modular transporters with their 288 individually steerable wheels were set in motion late on Corpus Christi evening and manoeuvred the bridge as close as possible to the tracks. A lattice boom crawler crane then took over on the opposite side of the tracks and gently lifted the steel giant over the tracks.

A total of 500 tonnes of counterweights were needed so that the crane monster could hold half the bridge load of 680 tonnes. These were brought in by 20 articulated lorries, while 70 lorry transports were needed to erect the crane. For hours on Friday morning, the bridge was suspended from the crane on one side while it was attached to the eastern abutment. At midday, the crane then lowered the striking tied-arch bridge onto the western abutment, accompanied by applause from the numerous spectators. The work seemed slow, but the time pressure was great. Deutsche Bahn had only closed the railway line between Niederrad and the airport for 24 hours.

The Donges team on site was visibly satisfied and proud of the smooth installation process. ‘On a lift like this, it’s important that everyone knows what their job is and that everyone communicates well with each other. We are an experienced and well-rehearsed team and recognise our responsibility for the safety of those involved and the structure. A big thank you to everyone who made this great engineering achievement possible,’ says the responsible Donges project manager, Aaron von der Heyden.

A new tied-arch bridge will be built near Bad Camberg in 2025

Congratulations to our bridge construction team on the new contract! Together with the construction company Albert Weil AG, we have been commissioned by DB Netz AG to build the new Erbach railway overpass near Bad Camberg.

Approx. 720 tonnes of steel are required for the 2-track tied arch superstructure with reinforced concrete abutments. The entire steel structure will be manufactured at our plant in Darmstadt and then transported to the construction site in central Hesse using heavy goods vehicles. There, the components will be welded together at the pre-assembly site to form the approx. 60 metre long bar arch and then the supporting structure will be driven into its final position in October 2025 using SPMTs (Self-Propelled Modular Transporters). A particular challenge for our assembly crew will be to install the bridge precisely during a shutdown period.

 

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.

Donges pushes bridge Overfly over Nuremberg East interchange

The bridge structure 3-1 Overfly transfers an exit of the motorway A6 Rifa Amberg over the motorway junction Nuremberg East and thus reconnects the motorway A6 to the motorway A9. The new construction will improve the performance of the Nuremberg East junction.

The bridge construction is a combination of continuous girder and cable-stayed bridge and can therefore be classified as an extradosed bridge. Donges SteelTec is constructing the complete bridge in the so-called cycle basement in 6 sections. After assembly, each section is hydraulically shifted longitudinally over the abutment and the concrete piers. The next section is then connected to the displaced end of the previous section until the opposite abutment is reached.

The steel composite structure, 588 m long in total, impressively spans the 115 m span with a total of 5 pairs of pylons. Up to 55 stranded cables form the cables of the stay cables. A total of approx. 8,600 tons of steel will be used for the 588 m long bridge.

The displacement of the bridge, including the already assembled pylons and cables, is carried out in 6 cycles with the maximum displacement distances of 115 m. A 50 m long cantilever bridges the free spans during shifting and compensates for the deflections of the bridge due to its own weight when it runs onto the next pier. Shifting takes two days per cycle. It takes place on special shifting rockers and is carried out with the help of greased shifting plates that allow the steel construction to slide forward successively. In this way, the shifting load that the hydraulic presses have to apply can be reduced to a maximum of 10 % of the bridge weight.

On 22.06.2023 the 3rd shifting cycle was successfully completed, the next components of the 4th cycle are currently being assembled. The steel construction work will continue until 2024.