ABSTRACT
The Large Hadron Collider (LHC) is the most recent and powerful accelerator constructed on the CERN site. The LHC consists of a 27 km circular tunnel, about 100 m underground, with eight sites positioned around the tunnel’s circumference. High-Luminosity LHC (HL-LHC) is a new project aiming to upgrade the LHC, at Point 1 (ATLAS in Switzerland) & Point 5 (CMS in France), in order to maintain scientific progress and exploit its full capacity with new underground and surface structures. The paper describes the HL-LHC design developed by the JV ORIGIN in Point 1 represented by Setec (France), Rocksoil (Italy), and CSD Eng. (Switzerland), & JV LAP in Point 5 represented by Lombardi (Switzerland), Pini Swiss (Switzerland), and Artelia (France).The construction works contracts were awarded in March 2018. The execution of the underground works started in April 2018 and is scheduled to be finished by the end of 2021.
