Opal Tower - Sydney Australia 28

[CivilEngAus]

https://www.news.com.au/national/ns...s/news-story/dad28af4aad5ff11cf968102635824f9

https://www.smh.com.au/national/nsw...ns-building-may-collapse-20181224-p50o4b.html

This could be an interesting and developing story in Sydney Australia. A 34 storey near new residential apartment tower in Sydney has been evacuated this afternoon over fears it is in structural distress with cracking noises heard during the day and one or more cracks developing; emergency services are treating it as a major incident.

Given we already have some of the toughest building codes in the world (although little to no registration requirements for engineers) it will be interesting to see how this plays out and what the crack(s) looks like to cause such a major emergency response.

 

[degenn]

TomFh and DeGenn,

if you want some reading on it,

Hi Rapt

Are you aware that this paper suggests using the current (2009) rules for mu=2.

 

[rapt]

DeGENN.

Seeing it was written before the 20018 code was written, it could not really tell you to use it. But it does say somewhere that this is being revised in the 2018 code.

3 of the 4 authors were on sub-committees or contributed to the 2018 code development.

 

[rapt]

DeGenn,

Actually it says "Current Code"!!

Most of the requirements in that summary table have been included in the 2018 code. Many were not in the 2009 code!

 

[QSIIN]

Degenn,

I think it is important to understand, as we've been discussing in the other thread, that mu and sp are actually a function of the design, detailing and behaviour of your structure. Not the other way around. Therefore, this article recommends using limited ductile values, but that is still subject to the design, detailing and behaviour of your structure.

The article points out that many designers choose mu and sp of 2 and 0.77, but then proceed to detail with low reinforcement% and in some cases, low ductility mesh. In the latter case, it's hard to argue to have a ductile structure when reinforcing with low ductility reinforcement.

As RAPT has said, a lot of what is in this article has been adopted to the 2018 3600, such as the fourth category of non-ductile structure.

 

[rapt]

Part of the problem with the code is that there are specific provisions in the earthquake section of the code that over-ride the general design provisions, especially for walls and columns in sections 10 and 11.

Section 14.4, 14.6 and 14.7 all control wall design and detailing for earthquake situations, including boundary elements, minimum reinforcement and confinement.

Also, this discussion should probably move to AS/NZ code forum.

If someone wants to continue it, start a thread there.

 

[hokie66]

Another report on the Opal Tower.

https://www.abc.net.au/news/2019-04...l-tower-unoccupied-four-months-later/11002796

 

[RVAmeche]

unfortunately engineers don't work as quickly as we'd hoped they would

That's a frustrating quote. Engineers are reviewing the designs and proposed solutions to make sure it's actually okay, in a residential building no less. What do they expect, to recalculate a single equation to say everything will be great?

 

[hokie66]

Consider the source.

 

[RVAmeche]

Sure, I just would've hoped a published quote would be something like "the process is taking longer than expected" or something like that.

 

[hokie66]

Well, a quote is a quote, like it or not.