7/25/2019 AISC Design Checks

1/22

111Equation Chapter 1 Section 1Allowable Strength Design Checks

Specification for Structural Steel Buildings (AISC !"1"#

($or doubl% S%&&etric ISections in !D structures#

'ist of s%&bols

Ae effectie net area ) net reduction factor for slender

Ag gross crosssectional area of &e&ber ele&ents

Aw area of web )a net reduction factor for web

Cblateraltorsional buckling

&odification factor

)s net reduction factor for flange

*pc web plastification factor

Cw warping constant * pg bending strength reduction factord oerall depth of the section

rteffectie radius of g%ration for

lateraltorsional bucklingE +oung,s &odulus

$cr critical stress r -- radius of g%ration . -a-is

$e elastic buckling stress r %% radius of g%ration . %a-is

ft flange thickness S- elastic section &odulus . -a-isfw flange widthS-c

elastic section &odulus referred to

co&pression flange$u specified &ini&u& tensile strength

$% %ield stress of steel S% elastic section &odulus . %a-is

/ shear &odulus of steel 0 shear lag factor h web height less the fillets &a- &a-i&u& shear force

h" distance between flange centroids n allowable fle-ural strength

I- &o&ent of inertia . -a-is wh web height

I% &o&ent of inertia . %a-is wt web thickness

2 torsional constant dX input ector

3

1

effectie length factor at start node 4- plastic section &odulus . -a-is3! effectie length factor at end node5pw

li&iting slenderness for a co&pact

web3 web plate shear buckling coefficient

36 length factor for torsional buckling5rw

li&iting slenderness for a non

co&pact web' length of the ele&ent

7c-aailable fle-ural strength in &a8or

a-is

7c%aailable fle-ural strength in &inor

a-is

7&a- &a-i&u& bending &o&ent

7p plastic &o&ent capacit%

7r- bending &o&ent in &a8or a-is7r% bending &o&ent in &inor a-is

7%c %ield &o&ent in co&pression flange

9&a- &a-i&u& a-ial force:c; :n aailable a-ial strength

:n allowable a-ial strength

:r; :a required a-ial strength

1

7/25/2019 AISC Design Checks

2/22

1< Design checks for ele&ent a-ial force and bending &o&ent

1

(a# ?hen

"

c

P

P @

A1c

P

P Assu&ing 36 1

7/25/2019 AISC Design Checks

7/22

reduced effectie width be

beis deter&ined as follows

when

1

7/25/2019 AISC Design Checks

8/22

d< Check no&inal co&pressie strength>If :nQ :a> check (J# L3@ else> check (J# $ails in co&pression

e< *eturn :nF< If fl S or web S

9et reduction factor calculations>

a< If fl 9S> )s 1

7/25/2019 AISC Design Checks

9/22

i *pc 7p; 7%c

ii< ?henpw

>>

1p p pw p

pc

yc yc rw pw yc

M M M

M M M

=

b< ?hen I%c; I% " *pc 1

7/25/2019 AISC Design Checks

14/22

< $or sections with slender flanges@

!

"

7/25/2019 AISC Design Checks

15/22

iii< Co&pression flange local buckling

7n *pg $cr S-c1< for sections with co&pact flanges@ the li&it state of co&pression flange local

buckling does not appl% 1 1 C 1 check (!# fails in shear