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TUNNEL CONSTRUCTION : HANDLING SEGMENTS
Segments are curved prefabricated concrete or cast iron arc shaped elements assembled by compression to form the coating of tunnels (train, subway, road, pipe, water etc)
The process consists of coating the tunnel with rings of concrete consisting of 6 to 8 segments assembled together.
Generally modern structure retaining methods are sufficient to ensure the final stability of the excavation in rocky ground. Nevertheless some terrain changes with time (swelling, mineral creep, clay consolidation etc). In this case it is necessary to assemble segments to form a permanent coating for the tunnels.
In the course of the construction of tunnel prefabricated reinforced concrete segments 30 to 40 centimeters thick are bolted together to form the coating. Seals are then placed between the segments of a ring and between successive rings in such a way that the process operates continuously. First objective to achieve the strength required to resist high compression quickly.
The manufacture of segments is a significant operation which requires the creation of a large manufacturing plant and very significant handling means, given the weight and size of these bulky loads. Indeed, the weight of a single segment can vary from 3 to 17 tonnes. On site lifters have many uses in the plant and in storage areas, standalone vacuum lifters and storage grabs are frequently used by our customers as well as stripping lifters, turners, triple clamps or tables.
To facilitate the gripping, the positioning and the installation of these segments directly in the tunnel boring machines, also produces customized segment erectors rotating 360*.