DYNA Grip® Stay Cables as Stabilization Cables for Germany’s largest temporary Bridge

Context

Recently, the largest temporary bridge ever erected in Germany was built between Rottenbuch and Bad Bayersoien north of Garmisch-Partenkirchen. With a total span of 266m, the steel truss bridge crosses the Ammer Gorge, accommodating the through traffic of 10,000 vehicles per day so that the historic Echelsbach Bridge can be partly rebuilt.

The temporary bridge consists of a modular construction system, weighs nearly 1,300t and is supported by 3 piers. The structure was assembled on site near Bad Bayersoien and was pushed across the gorge in 9 phases using hydraulic strand jacks.

Scope

DYWIDAG supplied a total of 16 Type DG-P19 DYNA Grip® Stay Cables including hydraulic dampers, 6 Type MER 6-3 DYWIDAG Monostrand tendons and 32 Type WR DYWIDAG Post-Tensioning Bars. Furthermore, DYWIDAG installed the hydraulic dampers and carried out vibration measurements on all stay cables.

Solution

In this case, the lower cable anchors were not attached to the superstructure, but anchored to the ground using DYWIDAG Ground Anchors and a transition structure consisting of steel bearing plates and DYWIDAG Post-Tensioning Bars. Additionally, due to their height, the piers had to be temporarily secured with monostrand tendons during the construction stage.

The biggest challenge during cable assembly was the fact that all working areas were very difficult to access. The bridge spans over a 70m high valley, the slopes of which are very steep and densely vegetated on both sides.

Since the lower anchors were only partly accessible by crane, some of the material and equipment had to be moved across the jobsite manually. On the pier heads, the working areas were also very narrow and only accessible by means of a crane basket.