The lack of independent checking on steel for highways has come to light after a two-year fight to get information off the Transport Agency.

Photo: Supplied / NZTA

Documents that the agency has been forced to release to RNZ by the Ombudsman have revealed the agency did not require independent tests of the steel on the Huntly section of the new Waikato Expressway.

They also show the agency had no requirement for independent steel testing at the Transmission Gully highway being built near quake-prone Wellington, and that there was a general lack of oversight of steel buying for the country's major highway projects.

RNZ first sought information two years ago, shortly after revealing that 1600 tonnes of brittle imported steel had forced the redesign of bridges on the Huntly Bypass.

The agency blocked multiple Official Information Act requests, primarily citing commercial sensitivity.

Read emails between agency managers and Huntly's contractors released under the Official Information Act here and here

The newly-released emails show the agency managers had not been told by Huntly's contractors, a Fulton Hogan-HEB joint venture, about the 1600-tonnes of bridge pile casings that returned a "massive failure" on brittleness tests, until RNZ asked about the failure.

The 600 huge steel tubes could not be used in the bridges as planned but had to be cut in half and used alongside additional steel reinforcing and concrete in a re-design the contractors paid for.

A contractor emails that the brittleness "would show up as bits breaking off the top of the steel pile" during a large earthquake.

The emails show the fallout from Huntly triggered a look at at least two other projects: Transmission Gully, and Mackays to Peka Peka, which are linked sections of State Highway 1 from Wellington to the Kāpiti coast.

Agency managers in early June 2016 discussed how neither of these two projects had any requirement for independent steel testing in their contract.

That's despite Transmission Gully's steel casings needing to hold up loads - they are "structural" - unlike Mackays to Peka Peka where the steel is primarily used to pour concrete into.

The contractors had "already confirmed that some of the casings are structural but at this stage they do not intend to carry out any independent testing", manager Chris Hunt wrote.

A day later the other manager said the contractor's designer was getting a brittleness test done, and perhaps other tests; but this was off their own bat.

"We [the agency] had no requirement for independent testing in our PRs [Principal's Requirements] as far as I have determined," manager Peter Simcock said.

At Huntly, it was the bridges manager for the joint venture who got the testing done in New Zealand.

"The decision to test the casings was instructed by me," Shane Wilton said by email. "The PRs and specifications do not require independent testing of the casings. Only mill certificates were required."

The New Zealand testing exposed the mill and testing certificates from China as wrong.

The local supplier at Huntly was listed major Steel & Tube; but who it dealt with in China has been kept secret till now by the Transport Agency.

The newly-released documents show the mill was Lingyuan Iron & Steel; according to Reuters, this mill usually only supplies China's domestic market, which is usually not the same as export grade.

The mill is not currently certified by the Australasian Certification Authority (ACRS) for steel.

The fabricator Tianjian Pengzhan Steel Pipe does have a relevant current international licence.

Only one of the two testing labs used in China, Test Center of Huludao Steel Pipe Industrial, is currently properly accredited; it appears the chemical testing of the Huntly bridge steel was by an unaccredited lab, Hongrun Materials Testing.

Steel & Tube said in media statements in 2016 that international lab SGS did a third, pre-export inspection. But these documents show that was only a visual check.

'Prudent' to insist on formal measures on testing

The emails show that after the Huntly failings, the Transport Agency chief executive Fergus Gammie, who had only just taken on the job, was briefed on steel.

Apart from Huntly, no other steel problems had been identified, the agency's principal structures engineer Nigel Lloyd said.

But then he pointed out the gap that existed because the agency had "no formal measures" to require extra tests in New Zealand, and it "may be prudent" to insist on this.

"Although the Transport Agency follows the appropriate New Zealand standard, we propose that an independent review be undertaken of the compliance requirements," Mr Lloyd wrote.

The agency declined to be interviewed but said in a statement it had reviewed its processes in 2016 and issued new mandatory rules on verifying steel for highways in May 2017.

“Many projects have instituted appropriate measures to address the risk of counterfeit mill certificates, independent laboratory test certificates, and shipping documents being issued for steel components that may subsequently fail during erection or in service,” it said in its technical advice about the 2017 changes.

“However, there have been inconsistencies in the approach across previous Agency projects.”

At Transmission Gully, the imported steel was coming from internationally accredited mills, and samples from every batch were being tested in New Zealand, it said.

As for telling the public in 2016 that it had had "no similar problems" with steel elsewhere, and not mentioning the failed steel tubes, the agency said: "The Transport Agency stands by this statement, which was made in the context of the issues experienced with the sub-standard steel used in the early stages of the construction of piles on the Huntly section of the Waikato Expressway."

This is an edited version of the original story as a result of new information being provided to RNZ by the Transport Agency on 8 June.