Strengthening of a rail bridge over the Parthe in Leipzig-Thekla

Thekla is a district in the northeast of Leipzig. It is bordered to the south and southeast by two rail lines, and to the east and northeast by the A 14 autobahn. The river Parthe flows through Thekla.

An over 100-year-old, 15 meter wide rail bridge crosses the Parthe. It no longer met modern requirements and had to be strengthened to take higher loads. This was to be done by applying additional concrete to the underside of the arched brick bridge. The job involved numerous challenges.

The river under the bridge had to be covered because the river and the land are conservation areas, so pollution with concrete had to be avoided. Because of the arch and the reinforcements for the additional concrete, the scaffold was assembled in four segments, each with formwork, next to the existing structure and then pulled under the bridge on teflon-coated sections.

The client then completed the 25-meter cantilever arch with a lateral formwork structure so that a 50-cm-thick concrete layer could be applied to the underside of the bridge. The formwork had to hold the shape until the concrete itself could support the loads of the bridge after setting. After the concrete had hardened, the scaffolding was hydraulically lowered and pushed out from beneath the structure.

The cantilever spanning of the Parthe River with our scaffolding met all requirements for nature and water protection. In addition, this is a new method for strengthening arched bridges. Deutsche Bahn has many of these structures, which require a special concrete formulation. The method is now proven and can be used for other projects of this type.