A US structural engineer says he remains confident to this day in an engineer's findings that the Canterbury Television (CTV) building had not sustained significant structural damage after the September 4, 2010, earthquake.
Evidence from California engineer Brian Kehoe opened the royal commission hearing into the CTV building's failure in the February 2011 earthquake this morning.
The building's failure claimed 115 lives.
Kehoe started giving evidence late yesterday and faced questioning from Willie Palmer of Alan Reay Consultants and the commission's assisting counsel Mark Zarifeh.
Kehoe said he endorsed findings from structural engineer David Coatsworth, who spent four hours doing a visual assessment of the CTV building on September 29, 2010.
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 the 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.
Department engineers to give evidence
Also due to take the stand today are two engineers from the Department of Building and Housing who prepared a report into establishing why the relatively modern CTV building had serious structural failures after the fatal February 2011 Christchurch quake.
The CTV Building Collapse Investigation Report, released in January 2012, was written by Dr Clark Hyland of Hyland Consultants and Ashley Smith of Structuresmith and claimed the building failed to meet some building codes.
The Department also investigated the performance of the Pyne Gould Corporation (PCG), Forsyth Barr, Hotel Grand Chancellor buildings.
At least 80 witnesses are being called during the inquriy, which covers the initial building consent issued by 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.