The Eye of the Fish

Leviathan
November 15, 2016

Hero Engineers

Engineers sometimes get a bad press, but I think it is worth singing their praises today. While we have all been huddled inside by the fire (or, if you don’t have a fire, then huddled by the cat), our Structural Engineering buddies have been slogging it out, going round town, inspecting buildings. Late at night, possibly all night long, down darkened corridors with potentially falling masonry, I just want to sing out how lucky we are and how well they are doing. So to does the China News, who published this photo of some of the intrepid engineers doing their rounds yesterday in the early hours of the morning. Thanks Alistar! Thanks Chris! Thanks other blokes I can’t quite see! Hope you got to use that deadly looking hammer on some recalcitrant doors. Somehow, having these folk assessing our buildings makes me feel just a little bit safer. And after all, isn’t that what engineers are there for?

City engineers inspect buildings in the central business district in Wellington on early November 14, 2016, following an earthquake centred some 90 kilometres (57 miles) north of New Zealand's South Island city of Christchurch.  A powerful 7.8 magnitude earthquake rocked New Zealand early November 14, the US Geological Survey said, prompting a tsunami warning and knocking out power and phone services in many parts of the country.  / AFP PHOTO / Marty Melville

City engineers inspect buildings in the central business district in Wellington on early November 14, 2016, following an earthquake centred some 90 kilometres (57 miles) north of New Zealand’s South Island city of Christchurch.
A powerful 7.8 magnitude earthquake rocked New Zealand early November 14, the US Geological Survey said, prompting a tsunami warning and knocking out power and phone services in many parts of the country. / AFP PHOTO / Marty Melville



The only slightly frustrating thing about all this is that they are presumably sworn to secrecy about the structural defects they find, and so we end up knowing nothing about it. Even down the pub, their lips are sealed, and we have to rely on media reports, which let’s face it, are as unreliable and sensationalist as saying Hillary Clinton will win the election. Of concern to me is that there are reports that the Stats building on the waterfront has had a floor collapse and “pancake”, and that Te Papa is still closed till tomorrow. Why so? How so? The Stats building, if I remember when watching its construction many years ago, has a concrete and steel frame construction, with an integral steel/concrete composite floor. How can this possibly have collapsed? Surely that’s just media bullshit. The ceiling might have broken free, I can believe that (its happened again at BNZ I reckon), but how can an entire area of floor just detach itself, without the rest of the building coming down as well? Seems…. highly unlikely. Yet this article on Stuff says it has. Perhaps it was just a huge pile of census forms that someone had to file, stacked in a big heap, that broke the floor. Will we ever know?
stats-the-old-way
The front doors broke free on the BNZ building, which is hardly a big deal, yet the press are reporting that the building there is suffering major damage as well. Really!?! Again?!? After last time!?! Perhaps, after all, it is not such a good idea to build down there on the waterfront…

Leviathan
15 - 11 - 16

From the DomPost website:
“Statistics New Zealand said on Monday evening that damage to the building may mean staff are not back in its headquarters for a year, but CentrePort had refused to answer questions, amid reports that parts of the building had “pancaked”. In a statement released by public relations firm SenateSHJ, CentrePort chief executive Derek Nind said that both Statistics House and Shed 39 – home of the Greater Wellington Regional Council (GWRC) – required more detailed inspections. Nind said the upper floors of the Statistics House, which had recently been upgraded, performed well, but there was substantial damage elsewhere.
“A small part of the ceiling on the ground floor and the first floor have partially dislodged after two concrete beams became separated from the exterior wall of the building.”
CentrePort has not said exactly how “small” the piece of ceiling which collapsed was. So far CentrePort has not responded to requests to interview Nind.”

starkive
15 - 11 - 16

uh-oh

http://www.stuff.co.nz/national/86497605/concerns-over-building-stability-in-central-wellington

Leviathan
15 - 11 - 16

The Fire Chief said “A major vertical beam has shorn”

Ummm, what the HECK is a vertical beam? Does he mean a column? I mean, a two year old could get that right. And this guy is the fire chief? Heaven help us!

Leviathan
16 - 11 - 16

The situation at the former ICI house (Stephenson and Turner, 1962ish) is getting more and more interesting. Is there is an over-reaction by the authorities in closing down the entire street and the neighbouring buildings, in case of the collapse of the building? The real question is – is it in real danger of collapse? No one here at the Eye of the Fish knows, and I haven’t been into that building for years, so we can’t say, although if what the Fire Chief says is true – and if a “vertical beam” is actually a column, and if a column really has shorn completely off, then it is in serious problem territory.

Now of course buildings have structural redundancy built into them so even if one column is removed, the building should still be able to stand up on the remaining columns (or else there would be instant structural collapse any time a column was damaged), but that would stress the other columns out even more.

I suspect that what has happened is this: the building has an eccentrically placed core, from what we can tell from the photos, and that means that it is a similar plan to the collapsed CTV building in Chch, which killed over 100 people, mostly Chinese language students all on one floor. It was an absolute tragedy, and so must not be allowed to happen again. But the CTV building was badly designed from the start, and then badly built, and had already had a patch-up job or two. The core was placed at one end, and large voids for stairs and lifts and ducts meant that the floor diaphragm did not connect well to the shear walls in the core. On this ICI House building, the core is entirely separate, and so bracing must be taken care of some other way. There are no large diagonal braces on the building, so the resistance must be from Moment frame connections. In other words, the joints between columns and beams must be stronger than usual, probably at both sides and hopefully the end opposite from the core as well.

If the broken column is 4 floors down from the top, then the danger is that the top 4 floors could fall over, or into the street. In my humble opinion, that’s pretty unlikely, but not enough info, so i can’t tell. This is not the Twin Towers, there has been no plane full of fuel cutting off half the columns, and there are no CIA operatives ready to blow it up. Most likely we have a long slow wait for demolition.

dennychups
17 - 11 - 16

ICI was built in 1965. It has a seismically separated circulation tower, one of very few of this building type. It has nothing in common with the CTV. It will be sad to loose yet another heritage building to an earthquake.

Leviat
17 - 11 - 16

The Architectural Centre has just published a quick – but highly informative – history of the ICI House, here:
http://architecture.org.nz/2016/11/17/ici-house/

There are many more stories still to be told on the building, mainly concerning the many, mostly abortive, attempts to add to the building, and to make a profit for the developer. None of them came about. Most of the designs were pretty bad – and rightfully declined by the Council, but would it have been better they had been built, rather than now, as it seems, a prime candidate for demolition.

Levi
18 - 11 - 16

Probably a little bit predictable: now that slightly less excitable engineers have had a chance to inspect the errant “vertical beam” inside (known to most intelligent people as a column), they have discovered that the building is in fact not “likely to collapse” any minute into the street after all.

http://www.stuff.co.nz/dominion-post/news/86551826/molesworth-st-to-reopen-threat-downgraded-for-building

After the quake – The Wellingtonista
18 - 11 - 16

[…] catastrophic structural failure. Eye of the Fish has some informed, measured discussion about the Stats and ICI buildings, and a rather more passionate rejoinder to calls for a red zone. [Update: this Herald article by a […]