Danube River Bridge project showcases the power of Doka as a single source for supporting complex construction

The challenge was to create a seemingly floating bridge connecting two sides of the Danube River in a visually sensitive manner. Unlike traditional suspension bridges, the constructor’s mandate was to build the bridge without visible intermediate support structures. This required large clusters of load-bearing cables to be stretched between anchorages above the connecting tunnel bypasses on either side of the water. With the support cables anchored directly into the rock of each riverbank, the first suspended bridge in Austria, weighing in at 13,000 tonnes, reveals unexpected elegance and grace.

The flexible Doka Ringlock scaffold was used for subsequent corrosion protection and assembly work on the tensioned suspension cables. The team harnessed the Ringlock flexibility to form a suspended scaffolding that supported construction work on the high-tension suspension cables ahead of the subsequent carriageway construction. A team of expert engineers from Doka Austria was responsible for planning the suspended scaffolding solution and optimizing the versatile Ringlock modular scaffolding to meet the distinctive requirements of the project. While a unique form was created, the suspended scaffolding used standard components of the rental system to deliver material, cost and time savings while simultaneously ensuring the site safety of construction personnel.

The overall construction necessitated on-site auxiliary and suspension ropes, in addition to suspension girders, which joined with the suspension ropes. Günther Keuschnig, Managing Director of Joint Venture A26 Danube Bridge (ICM-MAEAG-F-PILE), says: "The flexibility of the Ringlock scaffolding system was the ideal answer to our demanding requirements, such as covering very challenging geometries."

The Ringlock scaffolding complemented the activity already undertaken by Doka on the critical project. In 2022, Doka was responsible for making customized formwork that created some two anchor blocks with max. 120 anchors each that hold the cables and, in turn, extend up to 70 m into the rock of the riverbank (see pictures here). To meet the demanding strength needed to support the cables, more than 3,650 m³ of concrete were poured. One single pour of 450 m³ of concrete required the use of the innovative digital solution Concremote, which uses sensors to continuously monitor the temperature of the concrete during curing. This knowledge allowed the cooling water systems to be activated at the right time to reduce temperature stresses that can lead to cracking and ensure the integrity of the concrete strength.

“For this high-profile infrastructure project, it is clear that the whole of our contribution is greater than the sum of the individual elements. We are proud to have provided three essential components to this project. As a single source for formwork, scaffolding and digital solutions we can enhance our contribution to an efficient, safe, and streamlined construction process. At the same time, we have demonstrated our technical expertise in the field of scaffolding solutions. With the A26 Danube River Bridge, we have proven our value to high-quality constructors and look forward to supporting more complex construction projects in the future”, says Harald Zulehner, CEO of Doka Austria.

The resulting 300-meter-long and 22.5-meter-wide single-span suspension bridge is scheduled to welcome its first vehicle crossings in mid-2024. It will dramatically improve transport routes and relieve Linz of 20,000 vehicles per day.