Spectacular (re)construction

On Place de la Gare in Luxembourg City, the joint venture between Félix Giorgetti, CDCL and Poeckes is transforming the shell of CFL's historic headquarters.

The project involves the construction of a new 24,000 m² building to house the group's 1,200 employees, while preserving elements typical of the architecture of the period, such as its façades, frescoes and monumental staircase. And at the current stage of the works, that's almost all that's left of the old building, as the site entered its most complex phase a few weeks ago.

As a reminder, the old structure consisted of two buildings. The first, six storeys high, was completely demolished, with the exception of its façade.

The second, ten storeys high, was completely gutted and then rebuilt from the inside out, including the slabs, while preserving the exterior walls. An ingenious methodology was used to achieve this.

  "We divided the surface into four distinct zones, explains Josu Puelles, works manager. First we demolished zones 1 and 3 to their full height, while zones 2 and 4 ensured the stability of the structure. Then we pour new slabs before repeating the operation."

At the same time, the team carried out delicate earthworks under the building to incorporate two new basement levels. The site machinery, transported by crane, had to operate in extremely confined spaces, making the operation as impressive as it was complex.

On the left, beneath the stabilised facade, earthworks are continuing towards Rue du Fort Neipperg. Here, teams are digging down to -2, and even -3 in some places.

To protect neighbouring buildings and ensure the continuity of rail traffic, a vibration and ground movement monitoring system has been put in place.

"In the event of an alert, we immediately adjust our methods. For example, we use a hydraulic cutter, which is less aggressive than a jackhammer, to work in particularly hard rock" explains our site manager.

Cramped space

On the right, along the quays, construction of the extension to the head office has already begun. Here again, the task is proving difficult because of the configuration of the site. Between the existing building and the railway tracks, working space is reduced to a minimum. 

"Because of its 3.5 m overhang above the tracks, the building will have a mixed metal and concrete structure. We only have a small footprint, which means we can optimise the surface area while guaranteeing the solidity of the structure", explains our site manager.