On Wednesday 18 August, the final main tunnel breakthrough took place on the Dublin Port Tunnel, Eire. Contractor Nishimatsu has excavated two road tunnels with a total length exceeding 4.5km over the past two years.

After 15 years of planning, work began on the US$866M tunnel, which links the port to the new M1 motorway, in May 2002. The Herrenknecht TBM bored through limestone that was subsequently crushed to be used as the road surface for the tunnels.

Each of the twin tubes, one for northbound and one for southbound traffic, will house dual carriageways. Future work involves construction of the roads and fitting out the tunnels, which are expected to be operational by 2006 said reports.

Road haulage groups are campaigning for the operating height of the motorway within the tunnels to be raised from 4.65m to 5m in order to accommodate large trucks. Irish Transport Minister Seamus Brennan told reporters that health and safety consultants had argued that any alterations to the size and shape of the route could have severe safety implications.

He added when talking about the reports’ conclusions, “any change in the tunnel at this stage would be unsafe and that is some really compelling advice”. Although not detailed in the accounts, it seems reasonable to consider that changes to the design at this late stage could circumvent the overall design brief and cross-checking process.

Brennan said a final decision to changes on the tunnel profile would be made in early September, along with a ruling on whether trucks higher than 5m should be banned from the State’s roads.