Navigating Challenges in Strengthening a Super High Superstructure

DYWIDAG strengthened the existing double T-beam Holzbach Valley bridge in Steinenbrück, Overath, Germany. The company supplied and installed SUSPA-Wire EX tendons and DYWIDAG bar tendons, as well as supplied technical support on the superstructure.


Carrying the A4 motorway, the Holzbach Valley double T-beam bridge was constructed in 1971 and is 430 meters long. The A4 motorway connects the city of Cologne with the Sauerland region. Due to its heavy use, the bridge’s beams required strengthening by an external post-tensioning system. Tendons were installed while traffic continued to cross the bridge. 


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

  • Provide technical support


To strengthen the Holzbach Valley bridge, DYWIDAG installed an external post-tensioning system with 8 Wire EX tendons (approximately 400 meters long, including coupler elements). Additionally, the team completed the delivery, installation, and stressing of 48 pieces of DYWIDAG bar tendons.

As traffic continued to cross the bridge, the tendons were installed externally along the beam. Additionally, the bridge is very high, and the terrain below is difficult to navigate. The DYWIDAG team used a mobile platform to complete the installation of the longitudinal Wire-EX tendons.

Because the bridge is very high and the terrain underneath is difficult to access, an under-viewing device was used to complete the work.

The project was completed within the estimated time frame. Close cooperation between parties eased the challenges of installing the tendon system.

SupplyInstallationTechnical Support

Landesbetrieb Straßenbau NRW, Niederlassung Krefeld