In recent months, a number of jobs have showcased how gantry crane systems can provide a viable and, often important, alternative to traditional construction cranes.
Lifting firms across Europe have employed gantry crane systems to lift loads in situations where restricted sites and impassable locations meant crawlers, mobiles and rough terrains were unsuitable to carry out the lifts.
This type of application has long been seen at docksides and in factories, where gantry systems, such as RTGs and EOT cranes, perform work that ordinary cranes might not be able to fulfill. From loading and unloading Super Post- Panamax cargo ships, to moving steel coils and sheets in metal processing plants, they offer a suitable alternative lifting solution for many situations.
Now, they are making their way out of the quay and out of the factory and onto more conventional construction job sites.
Overhead work
This was the case in Limal, Belgium, when a railway cutting needed to be covered in order to protect nearby urbanisations from noise pollution created by the train tracks.
The roof structure was constructed from concrete girders, each with a weight of 80t, set every six metres. The weight and size of the concrete girders meant they could not be transported so were fabricated on site and, to add to the complexity of the construction, the tracks beneath were to remain operational to minimise disruption to traffic; a first in Belgium.
Construction firms Galère and CEI-De Meyer, both part of the Royal BAM Group of companies, worked together to construct the roof, and called on Belgium’s own Europa-Levage to provide it with a suitable lifting solution for this unique job.
Europa-Levage supplied an overhead travelling crane equipped with two 40t capacity hoists, both Verlinde Eurobloc VT5 chain models, to the site. The beam of the crane straddled the tracks, and as the concrete girders were moulded between the legs of the crane, the hoists, running along the gantry, lifted the minto position where they were fixed with corbelling.
The gantry crane system used in Limal was designed to work completely independent of the electricity network and without any external cabling. An electricity generator was fitted directly to the bridge of the crane, providing the power for all functions, while a radio remote control was installed to operate movement of the crane as it travelled and installed the girders.
Dam maintenance
In neighbouring France, French firm Meije utilised a semi gantry crane to allow essential maintenance work to be carried out on a hydroelectric dam in Truel, southern France. The gantry crane was installed along an 80m-long runway atop the dam, which allowed French electricity company EDF to service the gates of the hydroelectric dam.
The gates are serviced every 10-15 years, with surfaces stripped and repainted, and seals changed. The work is also part of a programme to renovate and raise the dam road to protect it against flooding. To allow this work to happen, the water needs to be held back from the dam in order to permit maintenance teams access in dry conditions. Cofferdams, watertight enclosures, are slid in vertically to dam the water off upstream of the gates and allow work to happen. Up to three cofferdams can be stacked together to seal off the dam.
Meije’s gantry system was installed to allow the cofferdams to be positioned, again using Verlinde hoists to lift and move the components. Like Europa- Levage, which equipped its gantry crane with technologies to eliminate all external cabling, Meije introduced a number of technologies and techniques to ease the lifting work.
During initial handling, two tandem hoists were used with two attachment points, helping stabilise the cofferdams, particularly during vertical movement. And a specially designed automatic release system was devised for the work that overcame the problems caused by installation under water.
This featured a fixed lifting beam fitted with two lifting hooks that used a balance trigger mechanism to automatically unhook the beam from the cofferdam. Once the cofferdam was in position, a counterweight tripped a lever that unhooked the cofferdam.
Meije’s semi gantry system allowed all handling of the cofferdams to be performed by a single machine, replacing the traditional two pieces of equipment: one for storage and the other for positioning. Using this gantry system, two operators were able to isolate the gates in four hours. This reduced both time and cost to EDF during this essential maintenance operation.
Eiffel Tower
Elsewhere in France, in the capital Paris, access was also an issue for Société d’Exploitation de la Tour Eiffel (SETE), the company operating the Eiffel Tower, as it renovated the hydraulic elevators running up the monument.
Hydraulic systems, press cylinders and accumulator cylinders of the west elevator were swapped out by SETE; the first time in 100 years of operation they have been replaced. They have been replaced by components that are as technically similar as possible to the original equipment, in line with the wishes of tower creator Gustave Eiffel.
French construction firm Baudin Chateauneuf was tasked with this work, and called on a 17m-long gantry crane to carry old components out, and new components into the tower.
The gantry was installed through a gap in the metal framework of the tower, and equipped with radio-controlled hoists that are able to pick and carry the 16m-long and 20t hydraulic systems.
While the west elevator is the first to be renovated, the second hydraulic elevator is to be renovated in a similar way in due course.
Through these applications, European lifting firms demonstrate how gantry systems can be employed as an alternative to traditional solutions. Across a variety of locations and environments, from carrying loads in and out of world famous landmarks to keeping commuters on the move, they show their capabilities to the lifting industry, with design and technological innovations helping overcome even the most demanding questions asked of them.
