The segments erectors are made up of a fixed structure and a moving one, both made of electro-welded structural metalwork and machined on machine tools.
The fixed part consists of two longitudinal beams on which the sliding guides of wear-resistant material are mounted. The mobile part, instead, comprises a fixed ring and a rotating one controlled by two planetary drives with sprockets coupled with the fifth wheel coupling with internal teeth. The segments that make up the ring are 4: the “invert” segment, or base segment, that weighs 7.5 tons, and three segments (two shoulder segments and a key segment) each weighing 6 tons.
The erectors are equipped with a mechanical pick-up unit in order to grasp segments. The mechanical pick-up unit grasps and retains segments for the entire duration of the positioning operations with three independent movements:
- Swinging = 5°
- Pitch = 5°
- Roll = 5°
A prob-drill is also provided with the erectors for carrying out additional drilling operations.
Erectors technical data:
- Total beams length = 7,000 mm
- Overall rotation = 220° on both sides
- Rotational speed = 2 rpm/minute
- Maximum load = 7,500 Kg
- Weight = 32,000 Kg
- Intrados diameter = 6,300 mm
The Tunnel Boring machines in question, for which the segments erectors were intended, will have a cutter head 6.5 metres wide and will be used to drill a hydraulic tunnel for the promising hydroelectric project “Gemeinschaftskraftwerk Inn”. The project will involve the construction of a water supply network in Tyrol, comprising a hydraulic tunnel about 22.6 km long that will be drilled using two hard rock double shield TBMs. The network will take 4 years to complete (2014-2018) and the hydraulic tunnel will produce about 400 GWh of electricity a year from renewable sources, providing energy for more than a hundred thousand homes.
Below photos of the erectors completely assembled at Galbiati workshops.