CTV engineer inexperienced on high-rises
Engineers had their hands "smacked'' if they put anything in a building design that was not absolutely necessary, a royal commission has heard.
Structural engineer David Harding is today giving evidence at a royal commission hearing into the collapse of the CTV building during the February 2011 earthquake, which claimed 115 lives.
Harding prepared the detailed design of the CTV building in 1985, while employed by Alan Reay Consultants.
He told the commission there was no tolerance from developers at that time for "conservative" design, for example including additional steel reinforcing that meant the building more than met the building code.
You would "get your hand smacked" if you put in unnecessary reinforcement, he said.
"If you couldn't justify it being in the building, you had to leave it out.''
The main reason for this was cost, he said.
"The objective was always to reduce the cost where possible, while still complying with the code."
Harding designed the CTV building while employed by Alan Reay, principal of Alan Reay Consultants.
He told the commission that, prior to the CTV design, he had only ever worked on single and two-storey buildings.
He had also spent the five years prior to designing the CTV building working on mainly roading projects for the Waimakariri District Council.
Due to his inexperience, Harding said he relied on Reay for guidance on the CTV design.
Harding said he was told by Reay that the client wanted the CTV building to look like the Contours building, on Durham St.
Due to his inexperience with multi-storey buildings, Reay gave him calculations for Landsborough House, at 287 Durham St, to use as a template.
Harding was also tasked with using a special modelling programme called Etabs to test the CTV design, even though he had never used it before.
The Etabs programme was designed to test how well a building would withstand vertical loadings such as in a seismic event.
Harding said that Reay had a strong hand in all the projects undertaken by the company, and was aware he had not used Etabs before.
Reay would have contact with clients and the architect, prepare preliminary calculations and decide where the major structural elements would go.
Harding would be shown the preliminary drawings and would then do the structural calculations, which he then gave to the draughtsmen so they could complete their drawings.
In earlier evidence, Reay said that he accepted his firm would be responsible for the CTV building failure were any shortcomings found in Harding's work.
ARCHITECT MAY APPEAR
The architect who designed the CTV building may be required to appear before the royal commission for cross-examination this week.
Alun Wilkie submitted a written statement to the inquiry, which was read this morning.
Wilkie said in his evidence that he had no involvement in the structural design of the CTV building, as this was solely up to engineers.
He only had architectural drawings for the building. Files relating to design and construction of the building had "long since been destroyed".
Wilkie stated the architectural design of the building was a "standard developers office building".
It was "very much in the mould of what developers constructed in that period". It was rectangular, with each floor a repeat, open plan with the lift shaft walls, toilets, lifts and stairwells grouped together.
Wilkie said he had no involvement in the observation of any structural work. The seismic performance of a building was "always'' up to the structural engineer.
He could not recall ever going to the CTV site while the building was being constructed.
"Suffice to say, to the best of my recollection, I cannot recall having any concerns about any aspect of the contractors work.''
Prior to design of the CTV building, Wilkie had not worked with Alan Reay Consulting Engineers before the CTV project.
Assisting counsel Stephen Mills QC said Wilkie had been overseas, but could still be required to appear at the hearing for questioning.
"If it has to be arranged, it will be arranged,'' he said.