No evidence of CTV steel reinforcing
MARC GREENHILL
Last updated 15:50 24/07/2012

STACY SQUIRES/Fairfax NZ JOHN MANDER: The United States engineering professor's evidence continues at today's inquiry into the CTV building collapse.

An apparent lack of steel reinforcing in some of the Canterbury Television building's structural elements was a concern, an inquiry has heard.

Professor John Mander, a Cantabrian now working in the Department of Civil Engineering at Texas A&M University, today told the Canterbury earthqaukes royal commission that he could see no evidence of spiral reinforcing in the beam-column joints.

The building was unlikely to be code-compliant without the steel reinforcing.

"From the forensic evidence, it's hard to see clues that there was some steel. You would see even if the concrete turned to rubble in the joints it would probably leave the steel behind," Mander said.

Evidence of the longitudinal steel could be seen, he said.

"It may well be that the way the beams were interlocked, and then the order in which the concrete was poured, there was no opportunity to actually put the steel in."

The absence of "drag bars" used to connect to the building's core in levels two and three probably contributed to the collapse, he said.

Mander was earlier rebuked for refusing to give a view on whether the CTV building was code-compliant.

The witness earned the ire of  commission chairman Justice Mark Cooper for refusing to answer a question from counsel Stephen Mills.

Mills asked Mander whether in his opinion the CTV building was "in all respects" code-compliant at the time it was permitted.

"If my understanding is correct, if the city council gave a permit to it, then it complied," Mander said.

"Every engineer knows that despite what may be permitted, there is inevitably going to be errors and omissions in every job. Some of them are small, some of them are large and some may come to light later on."

Pressed for his view on the code compliance, Mander said he would not give a personal view because "if the council considered it be OK, that's OK".

Cooper said: "Now just a minute; you can't say, 'I'll say I won't give a view'. Do you have one or not?"

"I don't have a view on that," Mander replied.

Asked again whether aspects of the design were code-compliant, Mander said it was possible some were not and the design "certainly wasn't best practice".

There had been a "liberal" interpretation of the code by the designers, he said.

"My own personal view is I wouldn't have designed it quite like it is,'' he said.

''I wouldn't teach students to [design] it like that either, but that seemed to be a fairly common practice, so evidently the council must have thought it was OK."
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...  he could see no evidence of spiral reinforcing in the beam-column joints....

"It may well be that the way the beams were interlocked, and then the order in which the concrete was poured, there was no opportunity to actually put the steel in."

The absence of "drag bars" used to connect to the building's core in levels two and three probably contributed to the collapse, he said.

These statements indicate that there was a specific type of deformed rebar not used in critical joints - ie it was absent.