Another bridge too far: Speed and weight limits on Hawke's Bay's Fernhill Bridge

Another of Hawke's Bay's highway bridges is under restrictions with an announcement on Friday of speed and weight limits on the 70-year-old State Highway 50 Fernhill Bridge between Napier and Hastings.

No date for the implementation was provided but in a statement, national highways management agency Waka Kotahi NZ Transport Agency revealed a recent assessment identified the two-lane bridge over the Ngaruroro River as not having the capacity to sustain heavy traffic demands.

The SH50 Fernhill Bridge over the Ngaruroro River between Napier and Hastings - 70 years old and set for speed and weight limits. Photo / Supplied

Six weeks ago the agency also announced restrictions on the 81-year-old Esk River Bridge on State Highway 2 between Bay View and Whirinaki with a 30km/h speed limit, adding to concerns about the highway between Napier, Wairoa and the East Coast.

The Ngaruroro River Bridge is one of several state highway bridges in the Hawke's Bay region that are more than 70 years old and will need to be upgraded in coming years, the agency says.

The bridge, built in 1948, is one of the longest on the Hawke's Bay and East Coast highways network, with approach span and central span lengths 18.29 metres and 24.38m respectively, with a total bridge length of 402.3m.

Central North Island regional manager maintenance and operations Jaclyn Hankin said that while the bridge is currently safe to use, it no longer has enough capacity to sustain heavy traffic demands, in terms of both the number and weight of heavy vehicles.

"We have put a 30km/h speed limit in place, alongside weight restrictions for heavy vehicles, to protect the bridge from overloading and additional wear and tear, and to ensure it can continue to be used safely, while we progress next steps."

Hankin said Waka Kotahi is commencing further investigations and detailed analysis to inform options that will support the application for funding.

"Ongoing inspections will continue, and additional monitoring may be implemented if required," she said.

Further details regarding when the speed and weight restrictions will come into force will be provided in the near future.

Meanwhile, detailed design for the strengthening of the Esk River Bridge is currently under way, and a process to secure a contractor is taking place in the hope of repairs - referred to as "construction" - starting in late January, subject to availability of materials.

The work will be undertaken at night to minimise disruption, but a full closure of the bridge will be required at times, Waka Kotahi says.