Aerolift offers several solutions for lifting and handling precast tunnel segments. In this article we like to share our scope of supply for the tunnel boring machine (TBM) industry. Our vacuum lifting devices are applied in various places in the process from concrete to tunnel. We offer solutions for production and storage facilities, but also for transport handling and inside the tunnel boring machine!
To handle by vacuum technology you don’t need embeds or any other lifting facilities. This means no damage due lifting facilities and no investment in embeds and the labour to fix them into the concrete. With Aerolift vacuum lifting devices you reach return on investment (ROI) within a year of operation.
With an Aerolift vacuum lifting device you can demould both tunnel segments and keystones easy and fast. Moreover, due to the divided lifting force of a suction pad it is possible to demould freshly poured concrete after a curing period of 8 till 10 hours. If you demould with embeds, the curing time is at least 24 hours.
The concrete tunnel segments are poured with the convex arch facing upwards (extrados), but delivered to the TBM with the arch facing down (intrados). This means the tunnel segments and keystones need to be turned 180 degrees. In the movie above turning is performed by a standalone turner. In the production facility all vacuum lifting devices are able to lift tunnel segments both intrados and extrados. This is possible due to an adjustable suction pad suspension.
In the movie the tunnel segments are turned with a standalone turning device. We also developed vacuum lifting devices which not only demould, but also turn the segments 180 degrees. Which vacuum lifting solution is required all depends on the situations and requirements of the customer.
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 also developed vacuum lifting solutions for inside tunnel boring machines. To come up with a good solution we not only looked at the technical aspect, but also in which environment the vacuum lifters need to operate. The space inside the TBM is very limited and dirty and also the extreme force of the TBM itself should be taken into account. Despite of this extreme situation the vacuum lifting devices need to last for many years with limited maintenance!
A vacuum lifting device which moves tunnel segments and keystones from transport to the erector. During handling the suction pad of the lifting device is able to turn 90 degrees to meet erector’s position. The rotating function is integrated in the vacuum handling device to limit the number of needed equipment.
We also developed vacuum lifting solutions which operate as part of the erector. It is important that the control system fits perfectly with the control system of the TBM. Both tunnel segments and keystones are picked up by the vacuum lifting device and positioned in the tunnel wall. To meet all required positions the device is able to turn 360 degrees! This is possible because the vacuum pump is placed in the TBM as separate unit. The tunnel segments are manually fixed with bolts. In order to gain access to the bolt holes of the keystone, the middle suction pad is able to retract and extend.
In the picture below you the middle suction pad extended.
The vacuum lifting device above has three suction pads. If a tunnel segment is lifted all three suction pads are active and if a keystone is lifted only the middle suction pad needs to be active. We developed an automatic keystone recognition. This system ensures the entire suction pad is active when lifting a normal size tunnel segment (no keystones). This is a safety provision to prevent human mistakes.
Most of the advantages of vacuum handling are already discussed in the text above. Below I list all the advantages of vacuum handling in the TBM industry:
More information about our vacuum lifting devices for the tunnelling industry? Contact our team.
