The 4.5km long Dublin Port Tunnel is Europe's longest urban motorway tunnel and the largest civil engineering contract ever awarded in the Republic of Ireland.

Design and supervision

The NMI Consortium, which includes Nishimatsu, Mowlem and Irishenco, appointed Grontmij, in association with Haswell Consulting Engineers, to carry out the design. Grontmij was responsible for the design and site supervision of all aspects of the cut and cover sections, including the passageways connecting the buildings, the positioning of all emergency niches, space proofing of the tunnel and the detailing of the architectural finish of the portals at either end.

Mechanical and electrical works

Grontmij is also responsible for the design and site supervision of all surface works including motorways, slip roads, bridges, buildings and river works. In addition, Grontmij is responsible for the design of the mechanical and electrical works and the various tunnel control systems.

Grontmij worked from project inception in 2001 until completion in 2006, designing over 65% of the finished tunnel. The tunnel was opened on 20 December 2006 by Irish Prime Minister Bertie Ahern.