Extra mile

To understand what holds the world together at its core calls for the utmost technological achievements: particles are accelerated to almost the speed of light and brought to collision. The heart of the facility is the three-cell, 1,100-metre-long ring tunnel with walls and ceilings up to 6.3 metres thick. The technical installations – 520 ventilation systems, enormous electromagnets, highly sensitive detector chambers, thousands and thousands of kilometres of power and data cables, underground crane systems, dozens of heavy-duty and fire brigade lifts – all this cannot be transported 20 metres underground and then assembled, but is created in a complex interlocking sequence with the shell construction.

2-metre-thick and 11-metre-tall walls with 6-metre thick slabs are not common. There is so much steel built in that you cannot even pass a finger through the reinforcement, and normal concrete does not flow through it. To ensure that construction progressed in an economical way, one half of each slab formwork was moved through the stationary part to the next section after striking. When the construction site was divided in an unscheduled way, the complete formwork set had to be doubled in a very short space of time. These represented extreme challenges that were solved together with the contractor.