The Globe laid bare
If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.
The Globe after the removal of all the sun baffles. Image: Lucien Fortunati.
Picture the general structure of the Globe. In simple terms, the building consists of two spheres, one inside the other. The inner sphere houses the Universe of Particles exhibition and the conference room and is connected to the outer sphere by two access ramps. “Each of these two spheres is made up of eighteen large supporting arcs,” explains Amaya Martínez García of the GS department, who is supervising the Globe renovation project. “These eighteen arcs are supported by braces, which ensure the structure’s horizontal stability. The main aim of the Globe renovation project is to replace the arcs that form the outer sphere.” This work must be done in strict sequence to prevent the structure from collapsing like a house of cards. To ensure that the building remains stable, 75% of the bracing must be in place at all times. The Globe has therefore been divided into four quarters that will be renovated one by one, and a 35-tonne shoring tower has been erected inside to take the weight when the arcs are removed (see the slideshow). One complete quarter of the structure – five 32m arcs (2 x 16m) weighing 6 tonnes each – has been renovated so far.
The new arcs are made of treated pine and so are more resistant to bad weather than the original spruce ones. “To protect the wood even more effectively against bad weather, the new arcs are covered with stainless steel fitted with gutters to drain runoff water, which is the main cause of the deterioration that we have seen occurring to the structural elements of the Globe and its ramps,” explains Martínez García.
The 1650 panels that make up the Globe’s sun baffles were all removed when the renovation work began and have been meticulously examined and assessed – one by one! – by CERN and the design office Charpente Concept. “The 70 sun baffles from the middle section, which had been the most exposed to the weather, needed replacing,” says Martínez García. “The rest will be restored through sanding, coating with a natural oil varnish and replacing certain damaged panels.” The ramps will be completely renovated and treated with a protective resin coating.
If all goes to plan, the Globe will open to the public once more at the beginning of April 2016 and its new frame should last another 40 years.
To see the full-size pictures, click here.
