Green Stone installs its first prefabricated lift shaft

"We dreamed it, so we did it", smiles  Romeo Martins, Stability studies Manager and Technical director of Green Stone, as the Giorgetti Group company has just succeeded in the challenge of installing a prefabricated lift shaft... in 5 minutes, watch in hand. Which is also the first time a Luxembourgish company has made such a piece.

The synergy of our skills

This performance is the result of a long and meticulous preparation. "For more than 20 years, the management and I have had the idea of producing prefabricated elements," says our engineer. Hence the launch on 15 September 2020 of Green Stone, our company specialising in the prefabrication of walls (especially in Poroton®), which is produced in Bastogne, Belgium. The plan is to also produce concrete parts. "In Luxembourg, you can order prefabricated walls, slabs and staircases, but not lift shafts. Why not? Because it is a very heavy element and requires special equipment to move it," he explains. But thanks to the Giorgetti Group's large fleet of machines, this is no longer a problem. All that was missing was a place to produce them.

The opportunity came at the beginning of the year, when CDCL joined our group. Located in Leudelange, the construction company next to our logistics centre has a hall equipped with a crane. The perfect place for Green Stone to launch its new activity!

"The traditional methods consist in using formwork panels or laying precast walls. But space is limited, it is more technical and takes longer to build. It takes about two days," says our engineer. With the prefabricated lift shaft, the benefits on the building site will be significant in terms of planning, labour and costs. 

And finally, after many months of study and preparation, the teams from Green Stone and the Lean & Methods department of Félix Giorgetti met on 18 October to install their first prefabricated concrete lift shaft.

11 tons of concrete

You could feel the stress and excitement  among the employees involved in this delicate operation. There is indeed a lot at stake for the future. "This is very important for us," confirms Alex Giorgetti, who is responsible for our logistics centre and process optimisation. If the test is successful, we can develop the prototype and standardise it for all our future projects. The time savings will be significant. For the Monza residence, our goal is to finish the shell in four months!"

If the test is successful, we can develop the prototype and standardise it for all our future projects. The time savings will be significant.

And as the mobile crane lifts the first lift shaft a few centimetres, the assembly holds its breath for a few seconds, before accompanying the 11-tonne piece to the truck. The other two elements (a second shaft and a dry area) are then moved in a more relaxed atmosphere. The convoy then cautiously sets off for the Monza residence site in Wickrange.

5 minutes flat

Less than an hour later, the moment of truth has arrived. "We sized the tower crane specifically to carry this load," says Romeo Martins. Before the eyes of the entire construction site, the lift shaft rises and flies over theconstruction site. The crane does not waver, the team accompanies the object to its final position. The whole operation took only 5 minutes. A record that was greeted with applause from the site!

A concrete sealant will then be poured into the integrated recesses to weld the parts together and to the slab. 

Of the three lift shafts that will be built in the Monza residence, two will be prefabricated. The third will be built in the traditional way, in order to measure the resources needed to build each one. While waiting for the figures, we can already welcome the development of this new solution, which will be decisive for our future projects!