Trenchless crossing
Linear Shoring secured the starting pit
With the laying of a new underground power supply line from the city’s central substation to its northern substation, “Innsbrucker Kommunalbetriebe AG” has completed the inner-city electricity supply network and improved supply reliability throughout the entire urban area. The scope of the construction work included crossing Salurner Straße.
The work was performed by Kraft & Wärme Rohr- und Anlagentechnik GmbH, with TEERAG-ASDAG as subcontractor. Particularly in view of the difficult traffic situation at the site, which included a high volume of road traffic as well as public buses and a tramline, the client decided to install the ducts needed to house the 110 kV power lines under the busy area of the intersection using a trenchless procedure.
The starting pit required to install the drilling equipment needed to be 3.10 meters wide and 7.80 meters long. In contrast to the original plan, the pit was not secured with conventional sheet piles, but with the Linear Shoring system from Emunds+Staudinger of thyssenkrupp Infrastructure. Apart from economic aspects, the main reason for the decision was a significant technical point: Rather than ramming the sheet piles, the installation of the Linear Shoring meant far less vibration in and around the construction site.
The shoring project on Salzdahlumer Straße had to be performed in a very limited space and without interrupting traffic.
Sensible alternative
With Linear Shoring, the shoring panels are held in vertically installed rails, allowing them to slide past one another. Once installed, they form an overlapping shoring system. The crucial design characteristic of the Linear Shoring system is the rigid boogie car, which ensures that the width of the trench during installation and removal remains constant at every stage of construction, a factor that ensures the process is both smooth and cost-effective.
As a rule, sheet piles are used to shore up the ends of the starting pit. As the struts of the shoring systems can only be used longitudinally to apply pressure and tension and cannot be horizontally loaded, so- called trench-end shoring adapters are integrated in the Linear Shoring system. Similar to the boogie car, they are guided in the steel section of the Linear Shoring soldiers, can be raised upwards at any time and close push to the trench-end edge of the shoring system.
Using this method, the sheet piles can be supported against the cross struts, which are resistant to bending.The crossing of Salurner Straße was completed within the scheduled time window, as planned.
Facts & figures
| Client | Innsbrucker Kommunalbetriebe AG |
| Scope of supply | Overlapping Linear Shoring consisting of Linear Shoring soldiers, interior and exterior shoring panels, interior and exterior top panels, and end shoring, including trench-end shoring adapters |
Facts & figures
| Client | Innsbrucker Kommunalbetriebe AG |
| Scope of supply | Overlapping Linear Shoring consisting of Linear Shoring soldiers, interior and exterior shoring panels, interior and exterior top panels, and end shoring, including trench-end shoring adapters |