Wellington Library attains 63% of earthquake rating but building code is wrong!

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Fred99

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#2233696 9-May-2019 14:06

geoffwnz:

Quakes are not all the same. Even the two Chch ones were very different with lateral movement in one and up-thrust in the other.

Both were primarily lateral movement (strike slip). There was upthrust / vertical acceleration in both quakes, a big difference was one went off nearly directly under a city, the other one didn't.

The extremely high (2.2 horizontal / 1.8 vertical) measurements in the Chch quake were outliers from one instrument close to the epicentre.

PGA in the CBD was about 0.8g. That's about what Wgtn should get every 50 years or so, and it essentially obliterated most the Chch CBD.

Sorry - I don't agree about "uniqueness" of the Kaikoura event WRT impact on Wgtn buildings. Long period movement with moderate acceleration is what should be expected and allowed for. A direct hit by something like the Darfield quake under the Wgtn CBD would be absolute disaster.

DjShadow

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#2233753 9-May-2019 14:41

The one thing that the Council has been quiet on is the Reading Cinemas / Courtenay Central complex in Wellington, been shut since early Jan but no word 5 months on.

Also I notice Queensgate in Lower Hutt has signs on all their entry doors indicating this is an earthquake at-risk building which is a little unnerving, still don't get how a building only 14ish years old (cinema end) was built so far below code.

mattwnz

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#2233765 9-May-2019 14:55

sbiddle:

The Kaikoura earthquake has fundamentally changed a *lot* of things that we thought we knew about earthquakes. The lateral forces and the way that the ground moved was very different to any quake we'd had previously - and the consequences were significant.

Many buildings constructed with precast slabs and beams saw movement (Stats house being the classic example) that was never foreseen or allowed for in many designs. This resulted in a lot of work with MBIE who released a lot of information around this late last year.

The initial report into the library several months ago showed that it still met 100% of NBS in many areas, however the same precast floors and beams that were 100% of NBS using some testing and lateral forces are now dangerous when this new information is used to calculate how they will perform.

The library closure is merely the tip of the iceberg. This particular issue is going to be huge, and we're only in the early days of it.

My understanding from speaking to a different council about a different earthquake closed building, is that the thresholds / requirements are a lot stricter with public buildings that house the public. So not sure if it is necessarily the tip of the iceberg, unless classifications, standards, laws, change. But it could be the tip of the iceberg for public buildings, as I understand this type of floor construction is quite common.

sbiddle

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#2233769 9-May-2019 15:09

DjShadow:

The one thing that the Council has been quiet on is the Reading Cinemas / Courtenay Central complex in Wellington, been shut since early Jan but no word 5 months on.

Also I notice Queensgate in Lower Hutt has signs on all their entry doors indicating this is an earthquake at-risk building which is a little unnerving, still don't get how a building only 14ish years old (cinema end) was built so far below code.

Queensgate has been a risk every since the quake - there had been lots of rumours floating around even after the demolition that many other parts of the complex were not great either - and when Stride wouldn't deny this you pretty much knew it was true.

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