Handling tunnel segments

Handling tunnel segments by vacuum technology. Aerolift designs customised lifting solutions for the complete handling process of precast tunnel segments. The lifting solutions are used during production, transhipment and in the tunnel boring machine (TBM). The unique features of vacuum handling are highly suitable to handle concrete products, such as tunnel segments.

Why choose vacuum handling

Specially for concrete products, vacuum offers many interesting advantages compared to other lifting methods:

  • Demoulding after 8 to 10 hours
  • Demoulding, lifting, and turning by one lifting device
  • Efficient during handling and the use of storage space
  • No damage or deformation to the tunnel segment
  • Less chance of cracks in the concrete
  • Easy and fast handling
  • Reuse of the same mould
  • Reduced chance of accidents, because no one has to be near the load before, during or after handling
  • Very safe due to the high safety standards of vacuum handling

Handling tunnel segments during production

Vacuum handling is very efficient for processes with a repetitive nature, like the production of tunnel segments. After 8 to 10 hours of hardening time the tunnel segment can be demoulded, thanks to the divided surface pressure of a suction pad. The mould stays intact and can be used again immediately. The tunnel segments are produced extrados, with the convex arch facing upwards. However, the tunnel segments need to turn 180 degrees for storage purposes. A vacuum turner enables you to demould, lift and turn in one movement.

We also designed a standalone turner. Demoulding, lifting and internal transport to and from the standalone turner is done by a vacuum lifter. The vacuum lifer is provided with an adjustable suction pad suspension. Enabling the lifter to lift the tunnel segments both extrados and intrados.

Handling a stack of precast tunnel segments

To handle a stack of precast tunnel segments we designed a clamp lifting device. The device is used to handle tunnel segments from the production or storage facilities to a truck. Or to carry the stack down the tunnel shaft into the TBM area.

Aerolift clamping device to handle a stack of tunnel segments

TBM equipment

Aerolift designs TBM equipment to lift, transport and turn tunnel segments inside the tunnel boring machine. In such design we not only look at the technical aspects, but also the environment in which the vacuum lifters need to operate. The space inside a TBM is very limited and dirty. Moreover, the extreme forces of the TBM itself needs to be considered. And despite the extreme situation, the vacuum lifters need to last for many years with limited maintenance.

TBM equipment to move tunnel segments to the erector

After a stack of tunnel segments is lowered into the tunnel shaft, they are transported to the TBM by a trolley rail. Next, one by one the tunnel segments are picked up and transported to the erector by a vacuum lifting device. During the transport to the lifting device rotates the tunnel element 90 degrees to meet the erector’s position. The rotating function is integrated in the vacuum handling device to limit the number of needed equipment.

Vacuum segment erector

A second vacuum lifting device operates as part of the erector. The control system fits perfectly with the control system of the TBM, enabling the possibility to pick up a tunnel segment to position it inside the tunnel wall. The vacuum segment erector is able to turn 360° to position the tunnel segment in any required position. This is possible because the vacuum pump is placed in the TBM as separate unit. All tunnel segments are fixed manually with bolts. In order to gain access to the bolt holes of a keystone, the central suction pad is able retract and extend.

Lifting keystones and tunnel segments

All vacuum lifting devices for the tunnelling industry are provided with three suction pads. If a tunnel segment is lifted all three suction pads are active. Keystones are lifted by turning off the outer suction pads. We designed a keystone recognition to prevent human mistakes. The system ensures all suction pads to be active when lifting a tunnel segment.