Complete renovation of the downstream reser-voir on the Sösetalsperre dam in the Harz

For the single-sided new reinforced concrete facing structures LOGO.3 wall formwork combined with supporting jacks are in use.

Demolition before new construction

Before renovation of the reservoir outlet could start, BST Becker Sanierungstechnik GmbH had to demolish all operating facilities, drive towers and the machine bridge. With the existing wing walls, the damaged sections were partially demolished by Wannenwetsch GmbH employing high-pressure water jet technology at up to 2600 bar.

Formwork planning to support work preparation and construction

Based on the construction drawings, the formwork experts in Steinach took charge of formwork planning for the general contractor, the Wernigerode subsidiary of the U&W Group, enabling construction work to progress in stages, each using about 280 m² of the LOGO.3 wall formwork system for casting the wing walls and pile structures.

For single-sided formwork on the wing walls, LOGO.3 is secured with supporting jacks. This involves the use of 2 x 3.00 m, 12 x 4.00 m, 4 x 6.00 m and 5 x 8.00 m high supporting jacks.

Particular attention had to be paid during the formwork planning stage to the fact that wing walls are inclined vertically and angled horizontally, with the top edge of the walls diminishing in height and needing to be incorporated in the pile structures.

All this was taken into account during the formwork planning stage, as the formwork drawings demonstrate clearly.

To create the correct angles of inclination, concrete upstands were planned and built as the rear support point for the supporting jacks for some of the concreting sections.

To be able to concrete the facing structures on the wing walls in no more than 2 phases, supporting jacks were planned in at heights of 8.0 metres, as shown in section 7 – 7. Platform brackets are planned in for all concreting sections, in each case on the upper formwork panel to create a safe working platform for concreting work.

Combination rails and double channel walers are planned to cover the joints between formwork panels. In addition, back and lifting forces anchoring were included in the formwork planning process.

"Thanks to this service from PASCHAL we can handle the installation of formwork for this renovation job, promptly and to a good standard", explained Johannes Frankenfeld, the site manager.