Aluminium design to AS 1664.1 Australian Code

[IH1980]

Hi,

Hoping someone can give me a little advice. I am looking at alu design to the Aus codes, which is a new code to me (1664.1). I have experience with BS EN 1999 and the old BS 8118 for alu design.

My first problem is that the grade is 6082 T6, which isn't listed in the code. Advice on the Australian Alu Council website suggests using the data for 6351 grade, but it doesn't list 6351-T6 under welded alloys either, and my section is welded. Not sure how to progress this!

Secondly, what is the purpose of Section 4.7, weighted averages? I am looking at a truss, formed from CHS. As far as I can see, in section 3 I will be looking at overall buckling and local buckling (e.g. 'flange, or wall' rippling) so what does the weighted average check do?

Thanks, Ian.

 

[186skier]

Per the AAMA 2010 - ADM1 - Aluminum Design Manual,

6082-T6 T6511 Extrusion (Unwelded)

Fty=38ksi
Fcy=38 KSI
Ftu-45 KSI
E=10,100 KSI
kt=1

I just purchased a copy of this manual so I learning my way through it. I recommend getting a copy. But it's not cheap.

Not sure about your second question.

 

[apsix]

I've always used the T5 value for 6351 from Table 3.3(B).
The welding destroys the temper so I don't think it matters much what the original temper was.

 

[IH1980]

I had arrived at using the 6351 values, i figured it was the best bet. I didn't really want to pick values from outside the code if I could help it , although if I have a problem I will look to other values if there are higher.

Apsix - have you some experience in AS alu design? I have sorted out most of my problems except one, which is the 'S2' limit for tubular products. i cannot work out S2 because typically you need to use the intercept of two equations (typically yield stresses 2 and 3 for slenderness), but stress 3 always comes out huge. It doesn't make sense because because the first stress is high relating to low slenderness as you'd expect, then it reduces slightly for the seconds, then jumps up by a factor of 10 for the third, which by rights should be the lowest! This means the graphs never intersect. I have another engineers calc where he has the same problem, so I wonder if it is a mistake in the code?