The FERMI@ELETTRA Free-Electron-Laser (FEL) project at the ELETTRA Laboratory of Sincrotrone Trieste, currently under construction and commissioning, will comprise a linear accelerator and two FEL beamlines. Two identical magnetic chicanes for bunch length compression will be installed in the linear accelerator (LINAC) tunnel. The first bunch compressor, at 300 MeV, has been recently installed and commissioned while the production and installation plan of the second one (at 600 MeV) is being defined. The chicane mechanical design has been achieved in collaboration with the supplier, Rial Vacuum srl. In this paper, the chicane mechanical design and the movable vacuum chambers are presented.