CTV inquiry: 200 holes cut in CTV: Driller
A concrete-cutting company owner has outlined his "hazy" memories of work his staff carried out on the Canterbury Television building, including claims his crew cut 200 holes in the structure.
Daniel Morris, the former owner of Knock Out Concrete, outlined his memories of the work to the royal commission today.
He said his staff drilled up to 200 holes into the CTV building, including about 50 into structural concrete beams, some time between 1995 and 2000.
He did not have any records to verify the work, and could not remember who contracted his company to carry it out.
"It was a long time ago. We did a lot of jobs," he said.
Morris said permits obtained to drill the holes were the responsibility of the contractor.
"We were all care, no responsibility. We cut where the main contractor marked. It was up to them to gain permits," he said.
"We were told to just cut through reinforcement if they needed us to."
Morris said this type of work still occurred "around town" today.
When he heard the CTV building had collapsed in the February 2011 quake, he "immediately thought about all the holes that had been cut in the beams".
He contacted the Department of Building and Housing and told it about the hole-drilling work.
"I told them about the size and number of holes drilled. I was not asked for an interview."
Morris said during questioning that it did cause him concern about this type of drilling having an impact on the structural integrity of buildings.
"I used to say, this isn't right ... to the odd foreman," he said.
"It was common cause to be drilling through beams back then, as far as I'm aware."
Morris accepted on questioning that his memory was hazy and he had no records to back up his recollections of work done to the CTV building.
Urban Search and Rescue engineers did not report finding drilled holes in the concrete beams.
Morris said the drilling may have been in the floor.
He had about 20 to 25 people working for him at the time of the CTV job.
He sold the business in 2000.
LACK OF GUIDELINES
Written guidelines and training on what to look for in earthquake damaged buildings to uncover structural damage would be beneficial in New Zealand, an inquiry has heard.
Evidence from United States engineer Brian Kehoe has continued at the royal commission this morning.
During questioning from commission assisting counsel Mark Zarifeh, Kehoe said in the United States there was extensive training available, however there did not appear to be any written guidelines in New Zealand for what engineers and building inspectors should look for in different types of buildings.
"Other than the guidelines for territorial authorities, I don't believe there is anything else," he said.
Zarifeh said a lack of training for inspectors and engineers conducting post-quake rapid assessments, perhaps through lack of opportunity, had "come through very clearly" in the inquiry so far.
Three city council building inspectors, none of them engineers, gave the CTV building a 'level 2' rapid assessment and gave it a green placard after they were assured an engineer would assess the building.
When engineer David Coatsworth assessed damage to the building on September 29, he was not assessing how the building would fare in a further major earthquake event and did not do a seismic analysis.
Kehoe said that in the US, training in assessing earthquake damage and its potential consequences was "widely implemented" in many jurisdictions.
"Anyone who does the inspections is supposed to go through training and have a card or certificate that shows they have gone through [it]," he said.
"Inspections are done with two people and the requirement is at least one of them is trained, in some cases be a licensed engineer but at least have the training."
Kehoe said the impression left after an assessment by Coatsworth on September 29 that the CTV building was safe to occupy was not surprising.
"There was no indication in the statement that if the next earthquake is bigger, there may be a problem."
However, in the US at least, the onus was on the building owner to get damage they were concerned about more extensively assessed.
ENGINEER'S REPORT BACKED
Kehoe he remained confident to this day in an engineer's findings that the CTV building had not sustained significant structural damage after the September quake.
Kehoe had started giving evidence late yesterday and faced questioning from Willie Palmer of Alan Reay Consultants as well as Zarifeh.
Kehoe said he endorsed findings from Coatsworth, who spent four hours doing a visual assessment of the CTV building.
Kehoe said in his evidence that, on the basis of Coatsworth's field notes and photographs taken on the day of his visual inspection, he agreed with the conclusion that damage to the structure of the building was "minor damage at worst" and "for the most part" did not warrant structural repairs.
Coatsworth found cracking and damage in the building. He did not have structural drawings of the building, though he had attempted to get them from CTV building manager John Drew and the Christchurch City Council.
Coatsworth concluded the structural damage was minor and did not require a more detailed structural analysis. He recommended repairing the cracks he found, but did not follow up on whether it was done.
Kehoe agreed during questioning that the building had sustained a "design event", meaning that it had undergone the pressure it was designed to withstand in the September 4 quake.
However this did not necessarily mean it had lost capacity to withstand more.
The results of September 4 earthquake was damage to non-structural elements, he said.
Tenants had raised concerns about the building shaking more after the September earthquake, and that it got worse after the Boxing Day 2010 earthquakes.
The CTV building was not assessed by an engineer after the Boxing Day 2010 quakes.
ENGINEERS TO GIVE EVIDENCE
Two consulting engineers who investigated the performance of the CTV building during the February 2011 earthquake will give evidence at the inquiry today.
Following the deadly quake, the Department of Building and Housing commenced a technical investigation to look at the performance of four relatively modern multi-story buildings in the central business district that has serious structural failures.
They were Pyne Gould Corporation (PCG), Forsyth Barr, Hotel Grand Chancellor and CTV.
Dr Clark Hyland of Hyland Consultants and Ashley Smith of Structuresmith prepared the CTV Building Collapse Investigation Report, issued in January 2012.
Evidence from Hyland and Smith will conclude week two of the eight-week royal commission hearing.
The commission has already heard witnesses who inspected the building before the disaster describe the post-September damage they saw.
This included three Christchurch City Council building inspectors and the only engineer to carry out a structural assessment.
Coatsworth was the only engineer to inspect the CTV building after the quake and he found there was no significant structural damage that would warrant it being closed.
However, he was adamant he never said the building was "safe".
More than 80 witnesses are being called during hearing, which covers 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 Boxing Day quakes in 2010.
The commission has until November 12 to complete its work.
- The Press