Though the long-term fix for a 97-year-old bridge in Tararua remains unknown, the cheapest option for ratepayers may be replacing the structure entirely.
By Rebecca Hogan of Local Democracy Reporting
Alfredton bridge has been open with restrictions since the middle of August, after it was completely closed in April when engineers found cracking within the structure of the critical route east of Eketāhuna.
Future repair and strengthening work for the bridge would cost anywhere from $2.6 million to $5.6m according to preliminary estimates provided by engineers to the Tararua District Council.
In total, the district council had spent roughly $80,000 this year on Alfredton bridge.
Tararua Alliance manager Daniel Erard said $22,000 had been spent on maintenance, $35,000 went towards a structural assessment and testing, and another $22,000 for the installation of barriers, necessary signage for restrictions and line-markings.
Erard said “we can’t comment on what the final solution might be”, but Tararua Alliance was preparing a business case for NZTA which would be ready by the end of the year.
The council would keep the community updated on the transport agency’s response.
Last week, NZTA cut funding for Tararua’s road network from 2027 – a move estimated to cost ratepayers nearly $1.3m over three years.
Without including costs associated with realigning the road, the current high-level estimate available for a full replacement of Alfredton bridge was $2.5m.
Engineers identified specific issues with carbonated concrete throughout the bridge as a contributing factor to the structure’s deterioration and said treating this concrete would cost more than replacing the structure.
Assessments were underway to weigh up the costs and benefits of each option and the risks of retaining the nearly century old bridge.
For now, only vehicles under 3.5 tonnes could cross – allowing school vans, which had been forced to take longer, alternative paths, to return to their original route – and it was restricted to a 10km speed-limit.
Alfredton school children were caught in the middle of the months long closure earlier this year, with some school buses forced to add an extra 30 minutes to the journey with the bridge closed.
Around 15% of the bridge’s daily users were heavy vehicles.
To further protect the bridge, the council recently installed signage to help prevent heavy vehicles entering the intersection.
– LDR is local body journalism co-funded by RNZ and NZ On Air.
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