Quincentenary Bridge underpass plan involves lanes ‘stilts’

How the new underpass of the Quincentenary Bridge will look.

Authorities at NUI Galway have resurrected plans to build a major underpass of the Quincentenary Bridge – which is likely to involve the construction of temporary lanes on ‘stilts’ for the N6.

The university was granted planning permission in 2013 for the project – to the south of the existing underpass – but it was ‘mothballed’ due to the economic downturn and the route selection process for the N6 Galway City Ring Road (outer bypass).

Now, the €1 million underpass project – 15 metres wide including cycle lanes and footpaths – has been put back on the agenda, with NUIG requesting an extension of time on planning permission for a further five years.

Unless otherwise specified by the Council, a grant of permission expires after five years – the underpass grant will expire in May 2018, unless the local authority grants the further five-year period requested.

The existing underpass which was built in the 1980s is considered totally inadequate to serve the needs of the college or its 20,000-student population.

The new underpass will be located 140 metres south of the existing one – to provide new pedestrian, cyclist and vehicular (including HGVs) links between the north and south campus and will involve the relocation of part of the existing roadway.

The plans include the realignment of the approach road and path under the bridge and a riverside walkway which will become part of the proposed ‘Greenway’ project, eventually linking the playing fields at Dangan with Fisheries Field.

In the application to planners for more time, NUIG said: “Commencement of the works has been prevented due to uncertainty regarding the route selection of the N6 Galway City Ring Road. The on-line route option involved the re-use and enhancement of the existing Quincentenary Bridge.

“This option has since been discounted and the new N6 road project is programmed to be lodged with An Bord Pleanála in the short-term.

“Funding for the project could not be sourced during the duration of the permission due to the prevailing economic conditions and associated lending restrictions. Since the beginning of the recession, government funding for Ireland’s third-level sector has been cut a considerable amount.

“However, having regard to reducing construction costs, and the ‘bottoming out’ of the economic recession, [NUIG] is confident that the proposed new underpass will be constructed in the coming years.”

The carriageway will be 15 metres wide – with a 7m road, two 2m cycle tracks and two 2m footpaths – and will have 5.3m of headroom to accommodate HGVs.

The bridge superstructure alone will take six months to build in three phases so that four lanes for vehicular traffic are maintained at all times:

■ Construction of a temporary footway/cycleway on the northern side of the N6, and close the southern side. The four traffic lanes would then move north, allowing the southern one-third side of the underpass bridge superstructure to be built and finished.
■ Divert the two westbound traffic lanes of the N6 southward onto the Phase 1 part of the underpass bridge. This would allow the middle one-third part of the new bridge superstructure to be built.
■ Construct temporary footway/cycleway on the southern side of the N6. Move the two eastbound lanes of the N6 onto the Phase 2 part of the underpass bridge, which would allow the final third (northern) of the superstructure to be built.

Now, the four lanes of the N6 would be moved back to their final positions, and the embankment beneath the new bridge could be excavated.

When the project goes to tender, a full Traffic Management Plan will have to be drawn up, which is likely to include the suggestion that the new temporary lanes for the N6 be built on ‘stilts’.

In the original grant of permission, planners ordered that lane closures on the Quincentenary Bridge must be aboided and the contractors should consider working at night.

A contract must also be drawn up between the Council and NUIG (and approved by Transport Infrastructure Ireland) which states that the college will finance the entire project, and ensure risks of delays are minimised.

A decision on the extension of time application is due in mid-August, and if approved, the university would have to complete the project by August 2023.