First German Project featuring Clevis Anchorages: The Markkleeberg Stay Cable Bridge
Recently, a new stay cable bridge crossing the B2 Federal Road was built for pedestrians, cyclists, emergency vehicles and utility vehicles in the town of Markkleeberg south of Leipzig. The bridge re-establishes the connection between Gaschwitz and Markkleeberg, which had been destroyed for a former open pit mine.
The new structure was designed as a fanned out, asymmetric, 63.81m long stay cable bridge with a superstructure consisting of a steel framework grid and a composite concrete slab. The two cable planes are accommodated in a fan by an approx. 33m high, H-shaped pylon that is slightly inclined towards the east and are anchored via the suspension cables at the eastern abutment.
The symmetric design of the roadway support results in equal stay cable forces in both cable planes as well as identical longitudinal main girders. The three DYNA Grip® Stay Cable pairs with 19 strands each in lengths of 47m, 36.5m and 27.5m were actively stressed using the Con-Ten method.
The two 27.5m long DYNA Grip® Stay Cables with 55 strands each that were installed as tiebacks did not have to be individually stressed. They were stressed by applying the tension forces in the three DYNA Grip® Stay Cable pairs. The DYNA Grip® Stay Cables with 55 strands are tied back in the abutment via 16 post-tensioned, 47mm Ø, 6.5m long DYWIDAG Bar Tendons.
All tendons were produced on the jobsite in advance. During one weekend, the B2 Federal Road was closed, and the bridge girders were installed and welded. Afterwards, the DYNA Grip® Stay Cables were installed using two cranes and a hoisting platform.
The stay cables are attached to the pylon via Clevis Anchorages. This special, space saving anchorage was used for the first time in Germany and for the first time for a smaller structure. Furthermore, external viscous dampeners were installed at the bridge deck to prevent excessive cable oscillation.
The Markkleeberg Stay Cable Bridge is the first project for which the general type approval could be used that was issued by the German Institute for Construction Technology, DIBt for the DYNA Grip® Multistrand Stay Cables. Consequently, in contrast to previous German stay cable projects, no project specific individual approval was required for the stay cable system, and the approval was provided quickly and easily.