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AS4100 Standard Grades and
Sections
Asst. Prof. Hang Thu Vu
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Lecture outline Industry uses AS4100 for general urose steel structure analysis
and design. !ithin "IV#$111% we will refer to this standard as the&ain design code. 'eneral &aterial roerties to use for design to AS4100
(iscuss availa)le standard grades and sections for design toAS4100
'rades* overview of availa)ility. +ield stress and tensile strength Sections* overview of availa)ility. ,ffects of shaes on section
caacity against loading actions Study the &eanings% usages and how to co&ute section
ara&eters I% -% S
ending of steel &e&)ers in elastic and lastic ranges Second &o&ent of area I ,lastic section &odulus - Plastic section &odulus S
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Basic parameter values and adjustment
for elevated temperatures
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Standard Grades
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Designation of Grades
Table 2.1 in AS4100. This ta)le gives values of yieldstress and ulti&ate tensile strength for steelroducts that co&ly with the re/uire&ents of AS%AS-S &anufacturing standards
Standard grade usually starts with the nu&)er of thestandard then characters and digits to stand for thegrade. ,2a&le* AS-S $35.1 $60#0
ote* AS-S 1654 uses a different syste& ofgrade designation. 7efer to AS-S 1654 Section
1.4
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Hot-rolled and cold-form grades Hot8rolled roducts 9lates and sections: are in
grades ;00% ;60% $00% $60% 400% 460% 600.These &ay )e o)tained with notch ductile/ualities 9with suffi2 #0 or #16: andor weather8resistant /ualities 9with refi2 !7:. !eatheringsteels are in 'rade $60 only
Hot8rolled welded sections are roduced fro&AS-S $3< lates= oularly in 'rades $00%400% !7$60
"old8for&ed hollow sections are with refi2es ".They are roduced in 'rades ";60% "$60% and"460. They &ay co&e with notch ductile #0/uality
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Hot-rolled and cold-form grades
(ata for design to AS4100 for
the &ost co&&only used
sections and lates in 'rades;60% $00% $60
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alues of !ield stress f!
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#$istence of residual stress
Tis of flanges and &iddle of we) cool and harden% &ore
/uic?ly than the rest of the cross8section.
The harder arts are in a state of co&ression. The>unctions% )eing held )y the harder arts and una)le to
contract as far as they would otherwise% are laced in
tension.
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Standard sections and plates
Steel roducts are rovided in standard siesand shaes. or &aterial availa)ility and cost
asect% it is reco&&ended to use standard
sections in your design. elow are funda&ental
sections
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Standard sections and plates
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#ffects of s"apes on mem%er strengt"
It is o)served that steel is roduced in various sections.
These include BlateB% Brounds% )ars and rodsB% BanglesB%BchannelsB and BI8sectionsB.
The I8sections are roduced as B)ea&B sections with I yy
&uch less than I22and Bcolu&nB sections with Iyyof closer
value to I22. Cost of these sections are roduced )y rolling red hot
steel. Cost sections have arallel flanges 9the BuniversalB)ea& and colu&n sections% and the channels:. So&eBtaer flangeB Is and channels are also roduced.
It is ossi)le to &a?e very large sections 9e.g. for )ridge)ea&s: )y welding late into the for& of an I or )o2.#engths are availa)le fro& a &ini&u& of 3 &etres to a&a2i&u& of $0 &etres. 7efer to Ta)le ;% DneSteel BHot7olled and Structural ProductsB% 6thed.
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#ffects of s"apes on mem%er strengt"
However% if )uc?ling occurs% the )uc?ling loadthat the &e&)er can withstand deends onsecond &o&ent of area I22and Iyy.
As the colu&n )uc?le a)out the a2is which is ofwea?er I% it is i&ortant to have I22and Iyyofsi&ilar &agnitude 9Eniversal colu&ns: whenthere is no lateral )racing for wea? a2is
&
&
'(kL
EIP
cr
=
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#ffects of s"apes on mem%er strengt" Bending* stress in a )ea& deends on the second
&o&ent of areaI
The )ending &o&ent which a )ea& can carry )efore itsflange starts to yield is CF-fy% where - is the elastic&odulus.
If the &o&ent is increased further% yielding sreadsthroughout the cross section. Total collase occurs at a&o&ent CFSfywhere S is the lastic section &odulus9study later:.
I
My=
ma$y
IZ=
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)ompare section properties for sections
of same amount of material Area A F 13000 &&;
Sread &aterial further away fro& neutral a2is to
&a?e rectangle% I shae 9310 E 1;6:% truss
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Bending of steel mem%er in elastic and
plastic ranges
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*evision+ Structural anal!sis
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*evision+ Structural anal!sis
!e want to calculate the &a2i&u& values ofactions 9&o&ent% shear force% a2ial force ..:for &e&)er design
ree )ody diagra&
Vertical reaction Ay% e/uivalent load P. At thecut of distance fro& left end* shear force V%)ending &o&ent C
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*evision+ Structural anal!sis The reaction at A is The e/uivalent oint load at a distance 2; fro& A is Ta?e &o&ent a)out the cut%
orce e/uili)riu& for y direction%
Ca2i&u& shear force haens at end Ca2i&u& )ending &o&ent haens at &iddle
wLAy&
1=
wxP=
&&
1
0&&
1
&wxwLxM
xwxwLxM
=
=+
wxwLV
wxwLV
=
=+
&
1
0&
1
wLV&
1
ma$=
,
&
ma$
wLM =
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Bending of a %eam mem%er
ending stress J22of the cross8section of a )ea& varies along the)ea& height
The )ea& is under &a2i&u& stress when CFC&a2and yFy&a2Fd;
The e2tre&e fi)re of the cross8section starts to yield when J22F fy.Hence% the &o&ent caacity that a cross8section can ta?e is
Z
M
I
My==
ZfM yy=
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Bending of a %eam mem%er
!hen the whole cross section yields the &o&ent
caacity increases to Cs. or design urose 9lower )ound of lasticity:% strain
hardening is ignored. The &aterial is ter&ed as ure
lasticity 9see )elow figure:.
It is assu&ed that the &a2i&u& stress that anywhere in
the cross section can reach is fy9see )elow figure:
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Bending of a %eam mem%er
- is ter&ed elastic section &odulus
S is ter&ed lastic section &odulus
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Second moment of area
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ormulae Second Co&ent of Area* also ?nown with other na&es
Second Co&ent Df Inertia% Area Co&ent of Inertia The &athe&atical e/uations to calculate the Second
Co&ent of Area *
y is the distance fro& the neutral a2is 22 to aninfinitesi&al area dA
2 is the distance fro& the neutral a2is yy to aninfinitesi&al area dA
=
=
A
yy
A
xx
dAxI
dAyI
&
&
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#$ample 1+ *ectangular section
( )
1&
,,..
.
..&
&
.&
&
&&
bdI
ddbybbdyydAyI
xx
d
d
d
dA
xx
=
+====
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#$ample &+ Hollo/ sections
7ectangular hollow sections
I sections
1&1&
.
&&
.
11 dbdb
Ixx =
1&&
1&
.. chbdIxx =
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#$ample .+ )ircular sections and
)ircular "ollo/ sections
4
4rIxx
=
( )4
&
4
14 rrIxx =
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eutral a$is (A' of non-s!mmetric
sections !hen the section is non8sy&&etric% we need to find the
location ycof the neutral a2is with resect to a datu&
which is usually chosen at the )ase of the section
The sign shows the contri)utions fro& all nele&ents of the cross section.
=
==n
i
i
n
i
ii
c
A
hAy
1
1
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2arallel a$is t"eorem The second &o&ent of area for the whole section
with resect to the located neutral a2is is calculatedfro& the Parallel A2is Theore&
I* the second &o&ent of area
Ii* the second &o&ent of area of ele&ent ith
Ai* area of ele&ent ith
di* distance )etween the neutral a2is of ele&ent ith
and the neutral a2is of the whole section
=
+=n
i
iii dAII1
&
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#$ample+ )alculate 3$$for section
d1F 610 8 $36.6 F 144.6 &&
d;F $36.6 8 ;60 F 116.6 &&
I22F ;002;0$1; K ;002;029144.6:;
K 102600$1; K 10260029116.6:;
Hence
I22F ;64%6;;%;60 &&4
=
+=n
i
iii dAII1
&
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#lastic section modulus
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ormulae
Elasticsection modulus- of a )ea& is the ratio of
a cross sectionLs second &o&ent of area I to the
distance of the extreme compressive fibrefro& the
neutral a2is
The elastic section &odulus &ar?s the yield oint ofthe &aterial when the &ost outer fi)re starts to yield
due to )ending &o&ent CyF-fy
ma$y
IZ=
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2lastic section modulus
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Define location of t"e 2A
The lastic neutral a2is PA% which is also referred to as
the e/ual area a2is% is the a2is that slits the cross
section into two e/ual areas. These areas refer to the
e/ual a&ount of fi)res yielded under co&ression and
tension resectively. or sy&&etric section% the lastic and elastic neutral
a2is coincide. They are the a2is through the centroid of
the section.
or non8sy&&etric section% location y the PA withresect to a datu& which is usually chosen at the )ase
of the section is defined
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)alculate S
S is co&uted as the su& of &o&ent of ele&ent
areas a)out the PA
S* the lastic section &odulus
Ai* area of ele&ent ith
ei* distance )etween the neutral a2is of ele&ent ith
and the lastic neutral a2is of the whole section.
==n
iiieAS 1
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#$ample+ section
yF$00
S F 9;00 2 40 2 1;0: K 9100 2 40 2 60: K 9$002 40 2 160:
Hence% S F ;530 2 10$&&$
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e$t lecture
Investigate the loads acting on the structure
in ter&s of Per&anent load 9dead load:
I&osed load 9live load: #oad factors to co&ly with li&it state design and
&e&)er design to AS4100
7eadAS-S 110.1*;00;