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AS 2870 vs NCC 1
- Thread starter LiamJS
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- #2
Retrograde
Structural
What are the actual disrepancies? Which tables in particular are you talking about?
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- #5
Thank you for your answers.
For example :
Stiffened Raft Class S Articulated Full Masonry: AS2870 Figure 3.1=500mm vs NCC 2019 Table 3.2.5.4b = 400mm
Another example:
Stiffened Raft Class M Full Masonry: AS2870 Figure 3.1=950mm vs NCC 2019 Table 3.2.5.5a = 800mm
There are others but I gave two examples. Another thing is that the standard is in "Pending Revision" status, and this makes things more confusing.
For example :
Stiffened Raft Class S Articulated Full Masonry: AS2870 Figure 3.1=500mm vs NCC 2019 Table 3.2.5.4b = 400mm
Another example:
Stiffened Raft Class M Full Masonry: AS2870 Figure 3.1=950mm vs NCC 2019 Table 3.2.5.5a = 800mm
There are others but I gave two examples. Another thing is that the standard is in "Pending Revision" status, and this makes things more confusing.
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- #6
Retrograde
Structural
I confess that I had no idea those tables are in the NCC. I have always just used AS 2870.
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- #8
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1
- #9
The NCC and Australian Standards are written by different groups who have different opinions and different goals.
Regarding the tables, I remember the divergence started with AS2870-2011. If you look at the earlier versions of AS2870 then they should be the same. You would have to confirm this, but I remember there being some big drought in the eastern states which caused cracking of walls on clay sites and this led to AS2870 designs becoming heavier. I think the NCC may have disagreed with the change and left it as is.
Most companies I know kept the original design that they had been using for decades and didn't follow the upgrade.
Hope this helps.
Regarding the tables, I remember the divergence started with AS2870-2011. If you look at the earlier versions of AS2870 then they should be the same. You would have to confirm this, but I remember there being some big drought in the eastern states which caused cracking of walls on clay sites and this led to AS2870 designs becoming heavier. I think the NCC may have disagreed with the change and left it as is.
Most companies I know kept the original design that they had been using for decades and didn't follow the upgrade.
Both the NCC tables and AS2870 are deemed to comply. Therefore following those tables is not mandatory.
Hope this helps.
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- #10
Thank you for the background story. That explains the confusion. Existence of two deemed to comply solution is really messed up. Then one should do calculations to go below any of them.
Another point is about which one is binding legally. While engineering part is not clear, legal part will be more confusing. They should solve this as soon as possible.
Neither of them are legally binding since they are both deemed to satisfy solutions. Unfortunately the structure of the NCC and the law is not taught in university. I would recommend reading up on Part A2 of the NCC (including "expert judgement") as it will put you ahead of at least 90% of engineers
Not quite same but I take BPEQ case below to be requiring 2870 with no room for judgement. Recommendation treated as mandatory requirement. Sounds like footings had no actual problem.
bpeq.qld.gov.au
Board v A
An engineer is reprimanded for unsatisfactory professional conduct in preparing slab and footing designs
bpeq.qld.gov.au
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