The CTV building could have gone through 100 major earthquakes and not been checked more thoroughly, a US expert says.
Californian Brian Kehoe has supported conclusions by Christchurch structural engineer David Coatsworth that the six-storey building was sound after the magnitude-7.1 quake of September 4, 2010.
Today he told the royal commission hearing into its February 22 collapse, which killed 115 people, that without evidence of structural damage, Mr Coatsworth was right not to do more invasive analysis.
"It's done all the time," he said.
"We would've done the exact same thing."
It could have gone through 100 earthquake events, and if no structural damage could be seen, then there was no need to look at it more closely, Mr Kehoe said.
The American structural engineer maintained that the building did not need to be red-stickered, and he agreed with Mr Coatsworth's October 2010 findings that it had performed well in the massive shaking.
Workers inside the Christchurch office block have given evidence that the building felt "sick" after the September quake, which sparked the killer Canterbury earthquake sequence.
Mr Coatsworth, of CPG New Zealand Ltd, was the only structural engineer to inspect the building before it came down in February last year.
He noted minor damage in his visual inspection, and green stickered the building - a decision that has haunted him ever since.
Yesterday he told the hearing that he keeps wondering whether he could have done things differently.
"I have examined and re-examined the 120 photographs that I took, and read and reread my notes and my report," he said.
Mr Coatsworth was unable to obtain structural drawings for the building from building manager John Drew or the Christchurch City Council when carrying out his inspection on September 29, which would have been "highly desirable".
New Zealand could follow the United States' lead in how rapid assessments are carried out, Mr Kehoe concluded.
Training was better in his homeland, and he thought the placarding system could be clarified so the public and building owners knew exactly what a red, yellow, or green sticker meant.
Whether a green placard means a building is 'safe to occupy' has been a point of contention so far throughout the hearing, which started last week.
Mr Kehoe accepted Justice Mark Cooper's observation that New Zealand places "much more reliance" than America on council inspections.
The royal commission hearing, which is trying to establish what happened to the CTV building before it collapsed, continues.
It is scheduled to last eight weeks.
