Challenges in Strengthening a Super High Superstructure

DYWIDAG strengthened the existing Highway bridge Lüner Bach in Unna, Germany by installing an external post-tensioning system. The company was responsible for the delivery, installation, and stressing of SUSPA-Wire EX tendons and DYWIDAG bar tendons.


The Lüner Bach Valley bridge was constructed in 1970 as a double T-beam bridge and is 336 meters long. It carries the A44 motorway west toward Unna and Dortmund, and east toward Werl and Soest. The bridge required strengthening due to increased traffic loads.


  • Produce, supply, and install tendons and bars to strengthen bridge

  • Provide technical support


To strengthen the Lüner Bach bridge, DYWIDAG installed an external post-tensioning system using 16 Wire-EX tendons (with individual lengths of 326 – 335 meters) in the longitudinal direction of the bridge superstructure. Additionally, the team completed the delivery and installation of 160 DYWIDAG bar tendons (measuring 2,10 – 2,20 m each) in the cross-section of the bridge superstructure for actively pre-stressing of the concrete anchors blocks.

Because the bridge was easily accessible from below, the team used telescoping platforms to complete most of the work. Traffic ran with minimal interruption as the construction was completed.

The project was finished within the estimated time frame.  

SupplyInstallationTechnical Support

Landesbetrieb Straßenbau NRW