Electricity for voestalpine's new electric arc furnace (EAF) in Linz is transported via an underground cable from the substation to the steelworks. The underground route replaces an overhead cable and offers the advantages of minimal impact on the appearance of the plant, shorter cable lengths and technical efficiency. A particular challenge was that suspended RINGER stair towers had to be used to access the 25-metre-deep cables – a special design for this major project.
The project is being implemented using four microtunnels with a total length of 1,700 m, which run at a depth of around 25 m. These are horizontal tunnel connections between vertical shafts that have been constructed at strategically important points on the factory premises. The shafts have a diameter of 12.4 m and serve as access and installation points for the high-performance power cables that will later be routed through the tunnels, cooled by around 20,000 m³ of water circulating in the pipes during operation. This will ensure that the power supply for the EAF will in future be invisible and space-saving, coming from renewable energy sources underground.
Safe access at a depth of 25 metres – with suspended RINGER stair towers
Working at these depths requires the highest safety standards for ascent and descent. That is why the construction company BT Bau GmbH opted for four stair towers from the RINGER modular scaffolding system for access to the four vertical shafts – tailor-made for use under these special conditions.
As classic assembly from the shaft floor was not possible, a special suspended construction was developed in close cooperation with the RINGER technical team, which not only ensured safety but also flexibility and stability. To anchor the stair tower, two HEB260 beams were bolted to the floor, protruding into the shaft. Safety straps attached to these beams secured and stabilised the entire structure.
Parallel to the ongoing excavation of the shafts, the scaffolding was gradually extended downwards in several stages, always secured and adapted to the respective construction progress. This special type of assembly impressively demonstrates how versatile RINGER modular scaffolding is, even under the most demanding conditions.
A scaffolding system for all situations
Thanks to its modular design, RINGER modular scaffolding can be used not only as classic working or protective scaffolding, but also as a stair tower in event areas, de-icing scaffolding, access systems, pedestrian walkways and even as formwork or, as in this case, as a suspended access solution for civil engineering shafts.
In addition, the RINGER modular scaffolding complies with all relevant standards and regulations:
- BauV (Construction Workers Protection Ordinance)
- ÖNORM B 4007 und B 5371
With a high load-bearing capacity, for example through steel decks for loads of up to 600 kg/m², quick connections via wedge locks and the possibility of exact adaptation to the respective construction site situation, it is the ideal solution for complex projects – even under extreme conditions.
