My pèroblema is that just in nc2008 I found nothing on aluminum structures for this I thought I had to report to ec9.
from a bit of experience that I believe that the various coefficients of contemporaneity should be different from those of steel. . .
However I thank you for the answers and if there are others I am always grateful.. .
Hi.
Hello inventor
I read your post and promptly respond: it's only been 2 years.
It is true: ntc 2008 contain nothing on aluminium.
- in ntc at point 4.6 indicates aluminum as non-traditional material whose use is subject to the approval of the superior council of llpp.
- on this point a circular has been issued by the Ministry of the LPs which has clarified that no prior authorisation is required for the use of aluminum.
- in relation to the calculation, the eurocode 9 must be used or, alternatively, the instructions cnr dt 208/2011 instructions for the design, execution and control of aluminum structures.
calculation considerations
calculation of aluminum structures is different from the calculation of steel structures because:
1) the elastic module is 700000 kg/cm2 (while the steel is 2.100.000).
This involves deformations more than 3 times than steel.
for this reason the verification formulas for the instability of aluminium rods are slightly different from those of verification of the academy.
2) the material is strongly influenced by welding.
aluminium is a very ductile material. the yield is fixed conventionally to the deformation 0.2 %.
in the first pages of the eurocode 9 there are the mechanical characteristics of the numerous aluminium alloys. the structural one in general is the en aw-6082 t6.
the acronym t6 indicates the heat treatment. the type of treatment affects the mechanical properties.
welds alter the material.
It is necessary, therefore, to take into account the fact that the welding, even small, along a rod alters the mechanical characteristics. in the calculation is taken into account by means of certain parameters that are absent in the verification of steel.
in conclusion:
the calculation of the efforts of a beam or an aluminium pillar is identical to that of steel rods.
what changes is the mode of verification of auctions.
as an example of sending a verification of local instability made with Eurocode 9 where welds are taken into account. (This is a verification of the compressed current of an American beam litec)
hello, next (in 2 years).
verification diflation of aluminium rods according to ec9 #5.9.4
test reticular rod
Axial project action at slu nd = kg 2232
design time at slu md = kgm 0
material en aw-6082 t6
yield voltage fy = kg/cm2 2500
elastic module 3.2.5 e = kg/cm2 700000
safety factor 5.1.1 gammam1 = 1,1
tube profile 50x2
profile area af = cm2 3,01
verification axis y
inertia section jy = cm4 8.7
wely elastic resistance module = cm3 3,48
plastic resistance module wply = cm3 4,59
radius inertia iy = cm 1,7
length rod ly = cm 50
beta-y bond coefficient = 1
length of free inflection loy = 50
snellezza asta loy/iy lamda-y = 29,4
3,14*(e/fy)^0,5 lamda1 = 52,56
lamdas=lamda/lamda1 lamdas = 0.55
parameter
= 0,7 = 0,7
reduction factor for flexional instability
(fi^2+lamdas^2)
parameter that takes into account the presence
localized welds wo wo = 0.75
parameter that takes into account the presence
localized welding wx 5.9.4. wx = 0,75
shape factor for the bending it holds
account of instability and softening a2 = 0.56
resistant axial action
nrd=af*fy/gammam1 nrd = kg 6840
resistant moment
mrd=a2*wel*fy/gammam1 mrd = kgm 44,29
5.9.4
verification 0.56 + 0 = 0,56 < 1 ok
