CTV needed a critical eye - engineer
Christchurch Earthquake 2011
A "critical eye" should have been cast over the Canterbury Television building, given the engineer's inexperience, an inquiry has heard.
The Canterbury earthquakes royal commission has heard evidence that the building's principal designer, David Harding, had limited experience with multi-level design and his employer, Alan Reay, did not check the plans.
Structural engineer Arthur O'Leary today told commissioners that failing to check a junior designer's work was "not something I would have done".
He could not comment on Reay's decision, but said Harding's competence would be a determining factor.
Commission chairman Justice Mark Cooper asked O'Leary if, in his experience, it was "usual or unusual" for plans to not be checked.
"The calculation wouldn't necessarily have been checked. A second [person] would have gone through the drawings to see if they looked right and were coherent," O'Leary said.
"It was before the days of formal QA [quality assurance], but it would be unusual for someone not to cast a critical eye over at least the drawings."
It was possible the larger firms in which he worked acted differently to smaller firms, he said.
Cooper asked O'Leary what conclusion he would have drawn had he been asked to check whether the plans "felt right".
A building with a sheer-wall structure "should be OK", given Christchurch's "moderate seismicity", O'Leary said.
"I don't know whether that was the common attitude in Christchurch, but it is a possibility the attitude was, 'It's a sheer-wall structure, it'll be OK as far as ductility is concerned'."
Cooper asked O'Leary whether he would have wanted more detail on the calculations had he been checking the building.
"I think I would have asked a few questions, yes," he said.
Harding's experience was relevant in determining whether his calculations should have been checked, O'Leary said.
"If it had been you, would you have left it to the unsupervised decision-making of somebody who hadn't designed a building such as this before?" Cooper asked.
O'Leary said he would not.
O'Leary earlier told the hearing the building was non-compliant at the time it was permitted, and some internal beams, beam-column joints and the north-wall connection did not meet the code.
The faults would have been "difficult to pick up", although an experienced reviewing engineer may have found them.
O'Leary said the south sheer wall may have separated from the floor slab earlier in the collapse sequence than expected.
Willie Palmer, the lawyer for building designer Alan Reay Consultants, asked if that was likely to have occurred before column failure.
"It would not surprise me," O'Leary said.
Today's evidence is focused on code compliance.
Structural engineers Douglas Latham and John O'Loughlin will also give evidence, and an expert panel will discuss elastic response spectra analysis.
More than 80 witnesses will be called during the eight-week hearing, which will cover the initial building consent issued by the Christchurch City Council, the construction and design, identification of a structural weakness in 1990, and the assessment after the September 4 and Boxing Day quakes in 2010.
The hearing was expected to finish this week, but was likely to continue next week because of time lost during the proceedings.
The commission has until November 12 to complete its work.
- © Fairfax NZ News
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