Engineer 're-lives' inspection of CTV 'over and over'
The only engineer to inspect the Canterbury Television (CTV) building after the September 2010 earthquake did not follow-up to see if the repairs he had recommended were done.
A royal commission hearing into the collapse of the CTV building in the February 2011 earthquake has continued with evidence from structural engineer David Coatsworth this afternoon.
Coatsworth inspected the building over four hours on September 29 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 in the building.
He did not believe the cracking was indicative of structural damage, but said 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 remedy this, and for the exterior walls, also assist with weather-proofing.
After reading his statement this morning, Coatsworth was questioned closely by lawyer Willie Palmer of Alan Ray Consultants.
Asked if he followed up on whether any action had been taken on his recommendations to carry out repairs, Coatsworth referred to earlier evidence from CTV building manager John Drew about a conversation they had regarding 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 a number of building inspections following the September quake and subsequent aftershocks, and said he assumed the repairs he had recommended for the CTV building had been completed.
He conceded he had 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 earthquake, he still had no idea if the repairs had been done.
A structural engineer who inspected the Canterbury Television building after the September 2010 earthquake found some "eccentricity" in the building, but did not think it was anything out of the ordinary.
He also put faith in the fact the building was constructed in the 1980s, when stringent building codes regarding seismic activity were already in place.
David Coatsworth, a senior structural engineer for CPG New Zealand, this morning opened evidence at a Royal Commission hearing into the CTV building's failure in the deadly February 2011 earthquake.
Struggling to hold back tears, Coatsworth said he had "re-lived" 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, the only structural engineer to inspect the building after the September quake, told the inquiry he carried out a thorough visual inspection of the building, but did not find anything which suggested it had sustained significant structural damage.
The assessment was carried out on September 29.
The building had already been green stickered following a 'level two' 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 if 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 said he had unsuccessfully attempted to get from CTV building manager John Drew and the Christchurch 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 said he observed 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 also isolated from the frame.
However he said 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 earthquake sustaining only minor structural damage.
In his report, which he emailed to Drew on October 8, Coatsworth made a number of 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 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 to other elements.
"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 concluded reading his evidence by offering his condolences to those who lost loved ones in the building's collapse.
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