The Dublin Port Tunnel involved the construction of twin road tunnel linking the commercially important Dublin Port to the ring road around Dublin, thereby diverting movement of heavy good vehicles through the City Centre. The tunnel alignment passed beneath the Dublin Area Rapid Transit (DART) Railway lines, a key commuter route. The railway embankment was built on very poor ground, and to construct the tunnels assure the safety of passenger trains, a pipe-arch support structure was required, and within which tunnel excavation was undertaken using small headings. The pipe arch structure was constructed by pipe jacking interlocked, 1.22m dia x 16mm thick, Grade 355 steel tubes of 60m length.
GCG was engaged by Charles Haswell Ltd as part of their design team for the Construction Design and Build Joint Venture. Our role in the DART crossing included providing on-site geotechnical expertise during the ground investigation, pipe jacking work and ground treatment works, and then acting as the Design Team Leader at Haswell’s office for completion of the tunnel excavation and support design. Years later, GCG provided technical support to the contractor during the claims arbitration process.