CTV engineer did not check repairs
The only engineer to inspect the Canterbury Television building after the September 2010 earthquake did not follow up to see whether the repairs he had recommended were done.
A royal commission hearing into the collapse of the CTV building in the February 2011 quake continued this afternoon with evidence from structural engineer David Coatsworth.
He inspected the building over four hours on September 29, 2010, and filed his report on October 8, saying the building had not sustained significant structural damage.
However, repairs would be needed to fix "fine cracking" he found in concrete beams and walls.
He did not believe the cracking indicated structural damage, but it would have the effect of reducing the overall stiffness of the building.
He recommended the small cracks be repaired by epoxy injection, which would also assist with weather-proofing for the exterior walls.
After reading his statement this morning, Coatsworth was questioned by lawyer Willie Palmer, for Alan Reay Consultants.
Asked if he followed up on whether any action had been taken on his recommendations to carry out repairs, Coatsworth referred to evidence from CTV building manager John Drew on a conversation they had about contracting repairers to do the work.
While Coatsworth said it was possible that conversation happened, he had no specific recollection of it.
Coatsworth was involved in several building inspections after the September quake and subsequent aftershocks, and he assumed the repairs he had recommended for the CTV building had been completed.
He expected to be involved in the repair work but had not followed up to see if that was going to be the case.
At the time of the February 2011 quake, he still had no idea if the repairs had been done.
CTV building had some 'eccentricity'
Coatsworth earlier told the commission he found some "eccentricity'' in the building but did not think it was anything out of the ordinary.
He put faith in the fact that the building was constructed in the 1980s, when stringent building codes over seismic activity were in place.
Struggling to hold back tears, Coatsworth said he had "relived" the inspection "over and over in my mind, wondering if there was anything I may have missed".
He had examined and re-examined the photos he took.
"I ask myself if there was anything I should have done differently."
Coatsworth told the inquiry he carried out a thorough visual inspection of the building but did not find anything that suggested it had sustained significant structural damage.
The assessment was carried out on September 29.
The building had already been green-stickered after a level 2 rapid inspection by three city council building inspectors.
Coatsworth said he spent four hours in the building.
He began by walking around the outside, then went through each floor room by room, and also on to the roof.
His priority was to see whether the floors, columns or other structural elements had "yielded'' in the September quake.
He did not have copies of architectural drawings of the building's design, which he had unsuccessfully tried to get from CTV building manager John Drew and the city council.
Although he spoke to Drew about damage staff had observed, "I decided what damage to look for".
"I saw every column on every floor,'' he said.
Coatsworth did not perform a vertical alignment survey as part of the inspection. This was usually done when there were signs of liquefaction.
He observed that there was some "eccentricity'' to the building.
There was a disparity between the centre of stiffness and stiffness of mass.
Concrete-block panels on the west wall were isolated from the frame, he said.
However, it was unusual to have a building with no eccentricities at all.
"I was not alarmed by the amount of eccentricity," he said.
Coatsworth found cracks throughout the building, but concluded there was "no evidence of structural failure".
The building had performed well in the September quake, sustaining only minor structural damage.
In his report, which he emailed to Drew on October 8, Coatsworth made recommendations for repairs after discussing what he had observed with colleagues.
This included repairing the fine cracking he had seen through the building as this would reduce its overall "stiffness", as well as falling plaster he found on the ends of concrete beams.
"I do not know whether my recommendation was followed, and if so, what the results were.''
Coatsworth carried out a further inspection on October 19 following a request from Drew after an aftershock.
Apart from two cracks in north stairwell being "slightly larger", he did not think there had been more damage.
"However, as an engineer I do not use the word 'safe'. It is simply not possible to say a building is safe under all circumstances."
He conceded that a layperson might misconstrue that if a building had not been damaged, it meant it was safe.
"It was not my intention to imply this."
Coatsworth ended his evidence by offering his condolences to those who lost loved ones in the building's collapse.
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