Major steel failure on new Waikato highway revealed in documents

The Waikato River from Cobham Bridge. Photo / File

Documents released under the Official Information Act have revealed a major steel failure on a Waikato highway.

Emails between NZ Transport Agency managers and contractors for the Huntly section of the new Waikato Expressway revealed the bridge file castings were found to be substandard and had 600 huge steel-rod fails.

This was shortly before the Fulton Hogan-HEB joint venture.

Agency senior project manager Kevin Johnson told another manager in an email that these were to be used as "piling and structural support for bridges, flyovers and various structural elements".

The 12m-long, 450mm diameter rods were imported from China.

"They did fail a stringent brittleness test by an independent consultant a few months back," he said.

"But are otherwise in all respects satisfactory."

Instead, they were cut and used with concrete and steel reinforcement in a re-design which was paid for by the contractors.

The emails also showed brittleness tests, or Charpy tests, on the bridge casings returned "massive failure".

Testing in New Zealand also exposed mill and testing certificates from China to be wrong.