CTV building collapse - facts and opinions

[ralf-nz]

In this week's magazine of our professional engineering organisation IPENZ:

'This week there have been several more media reports on the collapse of the CTV building during the Christchurch earthquake on 22 February.
While many of those interviewed have indeed been experts, there is an agreed process for determining in detail what went wrong, and we are confident the expert panels assembled by the Department of Building and Housing and Royal Commission will do a thorough job.
On Monday, the TVNZ Breakfast programme interviewed engineer John Scarry. Mr Scarry stated that the CTV building did not comply with the Building Code – again, there is a process in place to determine what happened, and we simply cannot say yet whether Mr Scarry’s assertion is correct.
...
We are committed to supporting the current investigation process into building performance during the Christchurch earthquakes, and appreciate your patience. No doubt many more opinions and hypotheses will be presented in the coming months.'

[JandM]

Slim pickings in the news this week, that they're trying to make something out of nothing?

[ralf-nz]

Slim pickings in the news this week, that they're trying to make something out of nothing?

I don't know!
I don't watch these programmes, where this and similar 'facts' were 'reported', but other people told me that breakfast tv, close up, campbell live etc. did something on this topic this week...

[Hesh]

I vaguely remember watching something on Tele about this. They had one prof (structural engineering) from one of the US universities talking about the CTV building. This prof also used to teach at University of Canterbury.

[Duncan74]

Someone came out and said that the reinforcing mesh on the floor wasn't connected to the core with the lift shaftsby strong a enough connection. That strong connection was mandatory according to building code. They asserted that this was clear by the images of the lift cores remaining upright the building frame and floors collapsed and no longer attached.

But what the comment made in the first post on this thread is raising is that there's a lot more that needs to be established before you get from the picture to the facts. Are teh assumptions related to the design correct, and was there ever assumed to be a structural connection there. Was there a failure in one location that then resulted in a sequential shearing of other connections. Were repairs underway to damage caused by the first quake that left the building vulnerable? These things need to be checked in detail and in a rigourous and systematic manner. Jumping to one seemingly obvious cause may ultimately delay the establishment of the full picture that in reality is likely to be some combination of several issues. And it's very hard for people to research all thses things in any case, but with the glare of the media at this stage reporting on half truths (and sometimes just incrorrect data or interpretations of that data) then it makes the process even harder.

[ralf-nz]

I vaguely remember watching something on Tele about this. They had one prof (structural engineering) from one of the US universities talking about the CTV building. This prof also used to teach at University of Canterbury.

Given this the more issues I have. It seems this guy went to the media instead to the Royal Commission. Why? What for?

[Super_BQ]

Given this the more issues I have. It seems this guy went to the media instead to the Royal Commission. Why? What for?

I saw the program on TV. It appeared that the TV program seeked professional advise by travelling to the US to find more information. By showing the details to this person (who appeared to have a long history in earthquake engineering), it was clear he pointed out the problems with the design of the CTV building.

The issue that sparked my interest is CCC engineers questioned this issue about insufficient ties to the lift shaft. However in the usual manner, city councils will turn a blind eye if a 3rd party engineer can prove the design is sufficient. Ie. producer statements. If there's any changed to the way we build in NZ, the local city councils need to have more authority in what will work or at least raise the standards of the minimum code for such designs (to leave room for more tolerances).

Were repairs underway to damage caused by the first quake that left the building vulnerable?

The professor also mentioned that even after the September earthquake, the likelihood of the steel coming apart in the concrete can not easily be known. Yes it could be compromised but how could you prove it was what he was saying (ie. x-ray eyes? can't just look at the surface cracks) He suggested that modern buildings should be built like today's vehicles that have built-in sensors that will measure tolerances (that could indicate breaking points).

CCC downtown planners are suggesting a low-rise re-build. I question when is the likelihood that Christchurch will have another earthquake disaster?

[ralf-nz]

However in the usual manner, city councils will turn a blind eye if a 3rd party engineer can prove the design is sufficient. Ie. producer statements. If there's any changed to the way we build in NZ, the local city councils need to have more authority in what will work or at least raise the standards of the minimum code for such designs (to leave room for more tolerances).

That is just shy of being derogatory to our profession! But only just!!