Mayo motorists to potentially face six months of traffic diversions along N58

Motorists in north Mayo could face up to six months of traffic diversions between Ballyvary and Foxford if permission is granted to demolish and construct a new bridge over the N58 in Straide.

Mayo County Council have applied to An Coimisún Pleanala 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.

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.

Damage evident to both the south and north span of the Straide River Bridge

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.

READ: Emergency Mayo bridge works lead to multi-week road closure

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.

An Environmental Impact Assessment Screening report for the proposed development found that 'no significant adverse impacts to the receiving environment will arise because of the proposed works'.

In the planning report to An Coimisiún Pleanála, Mayo County Council stated that the proposed development will provide a significantly improved and safer road bridge in line with planning policy, and is in the interests of the proper planning and sustainable development of the area.

The case is expected to be decided by An Coimisiún Pleanála by the middle of next February.