AS3600 - Section 5 Fire Design
AS3600 - Section 5 Fire Design
(OP)
Hi all,
Just wanted to raise a point with the current (amended) Section 5 of AS3600.
Currently there is a big discussion in the office, about 600 x 300 columns in the basement of a 5 storey apartment complex.
"Back in the day" this column size was pretty stock standard, however now according to the new Section 5, the minimum dimension now needs to be 350mm for 2 hour fire rating with neta about 0.5, which of course isn't ideal from an architectural and parking space perspective.
The senior engineers think that the fire section just keeps getting more conservative with each amendment and update.
What are your thoughts on Section 5?
Nearly all carparks up until last year would technically fail the current fire section of our code (with 600 x 300 columns).
Just wanted to raise a point with the current (amended) Section 5 of AS3600.
Currently there is a big discussion in the office, about 600 x 300 columns in the basement of a 5 storey apartment complex.
"Back in the day" this column size was pretty stock standard, however now according to the new Section 5, the minimum dimension now needs to be 350mm for 2 hour fire rating with neta about 0.5, which of course isn't ideal from an architectural and parking space perspective.
The senior engineers think that the fire section just keeps getting more conservative with each amendment and update.
What are your thoughts on Section 5?
Nearly all carparks up until last year would technically fail the current fire section of our code (with 600 x 300 columns).





RE: AS3600 - Section 5 Fire Design
http://www.nceng.com.au/
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
http://www.nceng.com.au/
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
as to the other question:
As3600 Cl5.3.1 will send you to the euro-code where they will show a calculation of amount of ignored concrete which sets the a depending on grade of steel ect. This will enable you to have small sections however you may need larger covers and more steel. Basically it will allow you to have more options than the table allow.
http://www.nceng.com.au/
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
RE: AS3600 - Section 5 Fire Design
Unfortunately, it's a Class 3 building with more than 3 storeys (Type A), thus the basement carpark doesn't comply with the relevant concession. I don't think it matters much anyway, a fire engineer will probably be engaged anyway.
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
Also, if your columns are braced and less than 3m you can assume an effective length of 0.5Lu in determining phi Nu which increases the capacity by about 20% (if you have a slender column) and hence will reduce your neta.
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
Cl 5.6.3 (AS3600:2009, Amendment 2)
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
Sure does, this is the wording in the code:
"The effective length of a column under fire conditions may be assumed to be equal to the effective length at normal temperatures in all cases. For braced building structures where the required FRP is greater than 30 min, the effective length may be taken as 0.5Lu for all cases"
I'd be interested to understand the rationale when/if the Commentary is released.
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
From my understanding Nu varies with ku and thus isn't a single figure like Nuo or Nub?
RE: AS3600 - Section 5 Fire Design
Plot your interaction curve for the column under standard temperature conditions. Then draw a line from 0.0 through your design M*, N* point until it crosses the Interaction curve. It is the value of phi Nu at the intersection point
RE: AS3600 - Section 5 Fire Design
Thank you for clearing that up.
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
https://www.dropbox.com/s/gyw1dilnpk1pe08/Eurocode...
RE: AS3600 - Section 5 Fire Design
Just quickly perusing the document, seems as though alot of our fire code is an adaption of EC2...
I'm looking for methods to justify more slender elements (particularly walls + columns), will EC2 methods help achieve that?
I notice AS3600 formulas look similar but there are some additional multipliers/factors in there that push it to being more conservative?
(Also - the link only provides the PDF, I can't find anything that helps me add you on Linkedin!)
RE: AS3600 - Section 5 Fire Design
RE: AS3600 - Section 5 Fire Design
https://www.dropbox.com/s/4o7mwow972cs49b/Lecture%...