The Narrows Bridge may remain closed for months and a temporary one-lane bridge erected in its place while work is done to stabilise the riverbanks.
The NZ Transport Agency (NZTA) closed the Tamahere, SH21 bridge across the Waikato River last Thursday after it had been reduced to one lane since August 31. Today the agency advised the bridge would be closed until further notice.
NZTA Acting State Highway Manager Michelle Te Wharau said in a statement that the Narrows Bridge would remain closed until the river level dropped and a further assessment could be made of bank erosion damage.
The NZTA would start work this week to address the erosion and scouring issues that were identified before the bridge’s closure last Thursday, she said. This work involved drilling numerous reinforcing rods into the adjacent steep river banks and is expected to take up to four months to complete.
Once completed, the soil nailing, as it is known, would help stabilise and strengthen the river banks to protect the Narrows Bridge from further erosion.
The NZTA had also started immediate preparations to lay the foundations for a temporary one-lane bailey bridge in case the remedial works or other circumstances required the Narrows Bridge to remain closed, Te Wharau said.
The laying of new bridge foundations would enable a bailey bridge to be installed, if required, immediately downstream of the existing bridge within the fastest possible timeframe.
“We wish to assure people that the Narrows Bridge itself is structurally sound,” Te Wharau said. “The focus our concern is the erosion and scouring of the adjacent river bank.
“As much as we understand the inconvenience that closing this bridge has caused [for] the nearby residents and travelling public, the safety of the people using this bridge is our highest priority.”
People travelling to Hamilton International Airport on SH21 from the Tamahere side of the city are advised to allow approximately 30 additional minutes for their journey. The recommended route to and from the airport during the Narrows Bridge closure is via SH3 (Ohaupo Road). Detour signs are in place.