Work includes the construction of an excavation pit up to 8m deep comprising a contiguous pile wall with wood and shotcrete panelling in the north as well as a secant pile wall in the west. In the east and south, the encompassment of the excavation pit is provided by the existing walls of the underground garage. The retaining structure works are being carried out at the same time as the demolition of the existing building.

The secant pile wall is being constructed on the temporarily supported ceilings of the basement floors. The piles have a diameter of 750mm and 880mm.

"The tie-back work, including wallings for existing walls of the underground garage, is very labour-intensive. And archaeological digs in the course of excavation work in the northern area of the excavation are also anticipated," said Bauer project manager Andreas Hertenberger.

Further, the underground garage walls are underpinned with DSV bodies. In the southwest area of the excavation pit, pipe bracing with lengths of up to 30m are installed.

Bauer's tasks also include the construction of wells and the dewatering system. For the latter, an approximately 500m long drainage pipe to the Rhein river was installed that transports water at a rate of 4,800m³/h.

A Bauer BG 24 H is in use as well as a Klemm KR 704, KR 702 and a KR 806 rig for the anchor drilling work. Work began in early April this year and the completion of the entire new building, with a height of 69.5m and 17 stories, 182 parking spaces for cars and 208 parking spaces for bicycles, is planned for August 2022.

Got a story? Email: duncan.moore@aspermontmedia.com