Christchurch engineer deregistered after designing flawed shopping precinct

Christchurch engineer deregistered after designing flawed shopping precinct.
Christchurch engineer deregistered after designing flawed shopping precinct. Photo credit: Katie Todd/RNZ

By Phil Pennington RNZ

An engineer whose design of a multistorey in Christchurch's main shopping precinct was so flawed and "incompetent" the building was immediately an earthquake risk, has been deregistered.

However, the building still stands, and Joo Cho can still work as an engineer, albeit not registered or chartered - though he told investigators he has retired.

Authorities are trying to find out what other designs he may have signed off on.

Cho's structural design mistakes on the narrow eight-storey block at 230 High Street were only spotted by a newly graduated engineer peeking through a fence in 2017.

An Engineering New Zealand disciplinary committee has now found Cho's design "incompetent", barred him from applying for a new registration for two years and ordered he pay $12,500 in costs.

Cho told RNZ he is no longer working as an engineer but would say nothing further, including whether he had any plans to do so in future.

"If his actions had been left unchecked, the safety of the public could have been at risk," the committee findings said.

These show Cho refused to accept reviewers' criticisms and did not make the changes they wanted, and kept maintaining to the end that the building is OK.

However, two in-depth reviews in 2020 "both concluded that the building as built is beyond rehabilitation. This is extremely concerning", the findings said.

"Retrofit is not feasible for the building to be safely used as intended, so the building must be demolished," one of these reviews, for the building's owner, said.

Christchurch City Council is now paying other engineers to see if they can fix the building, hemmed in between two others overlooking the busy mall.

ENZ chief executive Dr Richard Templer said the problems appeared limited to this one building - but they are checking on that.

"We have been in touch with building consent authorities [councils] and Mr Cho's previous employers to recommend a check on any structures signed off by Mr Cho," Templer told RNZ.

They had had no feedback on that since 2020.

Councils do not typically keep easily traceable records of which engineer designs which building and Templer conceded "it's the firms that are more likely to be a conduit to that".

"It's probably worth noting that the design Mr Cho used is uncommon in New Zealand. So we don't think it is something that has been in very many buildings.

"However, as you say, we don't have a register of all buildings ... so we can't be sure. And of course, no one else does, either."

Cho got a Masters in engineering in 1997 and first registered as a chartered professional engineer - among ENZ's highest rankings - in 2008. He worked for the council before setting up his own firm Seismotech Consulting.

The weak licensing system of engineers allows anyone to call themselves an engineer, and to carry on even if deregistered - though if they are not chartered they can no longer sign off Producer Statements. The regime is being tightened, though that will take years.

Templer said since Cho maintained his chartered status through years of checks, it was likely the flawed High St design was an isolated case for him.

The High St block went up even despite the flawed design not being followed in the construction, a series of reviews since 2017 have shown.

Piles, columns, braces and foundations, stairs and seismic calculations all fell short of the Building Code, according to the reviews.

The new engineer who spotted the flaws, told his firm, which raised it with Cho, and told investigators he resisted: "We haven't got that acknowledgement and I might add, we still haven't got that acknowledgement. So that's what prompted me to basically sort of draw a line under it and say 'enough's enough, we need to expose this".

The findings said Cho "was unable to provide us with any evidence that there was any quality assurance undertaken, such as checking of the final design".

Cho defended the design while failing to back that up. He told the investigators he raised the issues with his client "but the client was not willing to pay for a review".

"He told us that he stands by his original design but if he were to design the same building now he would do it differently, resulting in a building that was overdesigned and more expensive.

"Mr Cho told us that he has left engineering and is now retired."

The council issued consent for the structural designs in 2016 and 2017, and accepted Producer Statements signed by Mr Cho to attest the structure was OK. The peer reviewers told investigators they only learned later that Cho had not addressed the design issues they raised.

The council refused to issue a final code compliance certificate in 2018.

The findings shed light on a report by RNZ two years ago that a council engineer's name appeared repeatedly on the plans as "senior structural engineer" at 230 High St. The council denied this was a problem.

The findings say Cho reported this "secondary designer" was working at the council reviewing structural work while working at another company part-time. Cho said the secondary designer "was competent to design the structure" in line with building standards.

But the council told investigators the secondary designer "was not involved with the approval of the building and the assessment for building consent was carried out by an external consultant".

The council asked the building owner Owner Soung Joon Kim for a detailed seismic assessment and has engaged another engineer to do yet another review, this time of the owner's review that recommended demolition.