New bridge through Mayo village give green light by An Coimisiún Pleanála

AN Coimisiún Pleanála have given the go ahead to Mayo County Council to demolish and construct a new bridge along the N58 in Straide.

Last year, Mayo County Council applied to An Coimisiún Pleanála for permission to carry out rehabilitation works to the Straide River Bridge which is located along the N58 in the village of Straide between Ballyvary and Foxford.

The proposed development is to increase the load carrying capacity and structural integrity of the bridge and will involve the demolition of the existing bridge superstructure and replacement with a new single span deck.

The River Moy Special Area of Conservation is immediately downstream of the site and as a result, Mayo County Council had to conduct an Environmental Impact Assessment Screening report for the proposed development which found that 'no significant adverse impacts to the receiving environment will arise because of the proposed works'.

In his report to An Coimisiún Pleanála, the inspector Niall Haverty stated that based on the information submitted, surveys carried out analysis provided, he was satisfied that the proposed development would not delay or prevent the attainment of the conservation objectives of the River Moy SAC and adverse effects on site integrity can be excluded and recommended that the development be approved.

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The Commission stated they were satisfied that the proposed development would not adversely affect the integrity of the European Site, in view of the site’s conservation objectives and approved the development subject to seven conditions.

During the demolition and reconstruction phase, it is proposed to close the N58 at Straide for up to six months with a traffic management plan to be put in place.

Southbound traffic will be diverted from the N58 north of Straide onto the R321 regional road before joining the N5 west of Bohola. N58 northbound traffic joining from the N5 will instead be diverted further east along the N5 onto the R321 west of Bohola before joining the N58 north of Straide. The total length of the diversion will be approximately 11km.

As part of an assessment of ten bridges in Mayo carried out in 2023, it was found that the existing Straide River bridge structure has a reduced 7.5 tonne load capacity due to bond failure between the concrete and steel beams with significant cracking, delamination and spalling visible to the deck slab.

It was proposed to replace the deck slab to provide a structure with a full load capacity to improve the structural integrity for the safety of road users. Following consultation with the Office of Public Works and Inland Fisheries Ireland, it was decided the existing pier and concrete apron will be demolished to improve conveyance through the structure with a new reduced height concrete apron constructed to maintain the existing low flow channel.

The proposed replacement deck would be formed of precast prestressed concrete beams with an in situ concrete deck infill and will have an approximate clear span of 10.8 metres and an approximate width of 11.8 metres.

In preparation for the demolition and reconstruction of the bridge, a three dam dewatering system will be erected in the river and it is proposed that all fish will be relocated downstream of the works area.

When the bridge has been rebuilt, it is proposed that the N58 will be partially reopened with a single lane closure to alternate as required for the remaining works.