Draft

3.1Steel 59

HP is a bearingpilesection.

Mis a miscellaneoussection.

Lareanglesectionswhich may have equalor unequalsides.

WTis a T sectioncutfroma Wsectionin two.

10 ThesectionmodulusSxof a W sectioncanbe roughlyapproximatedby thefollowingformula

Sxwd= 10 or IxSx

d

2

wd

2

= 20 (3.1)

andtheplasticmoduluscanbe approximatedby

Zxwd= 9 (3.2)

11 Propertiesof structuralsteelaretabulatedin Table3.1.

ASTM

Desig.

Shapes Available Use y(kksi) u(kksi)

A36 Shapes andbars Riveted, bolted,

welded;Buildingsand

bridges

36 upthrough8 in. (32

above 8.)

A500 Cold formed welded and

seamlesssections;

General structural

purpose Riveted,

weldedor bolted;

GradeA:33;GradeB:42;

GradeC: 46

A501 Hot formed welded and

seamlesssections;

Boltedandwelded 36

A529 Platesandbars

1

2

in and

lessthick;

Building frames and

trusses; Bolted and

welded

42

A606 Hotandcoldrolledsheets; Atmosphericcorrosion

resistant

45-50

A611 Cold rolled sheet in cut

lengths

Coldformedsections GradeC 33;GradeD 40;

GradeE 80

A 709 Structural shapes, plates

andbars

Bridges Grade36: 36 (to4 in.);

Grade50:50;Grade100:

100 (to2.5in.)and90 (over

2.5to 4 in.)

Table3.1:Propertiesof MajorStructuralSteels

12 Rolledsections,Fig. 3.3andweldedones,Fig3.4haveresidualstresses. Thoseoriginate

duringtherollingor fabricationof a member.Themember is hotjustafterrollingor welding,

it coolsunevenlybecauseof varyingexposure. Theareathatcool rstbecomestier,resist

contraction,anddevelopcompressive stresses. Theremainingregionscontinuetocool and

contractin theplasticconditionanddeveloptensilestresses.

13 Dueto thoseresidualstresses,thestress-straincurve of a rolledsectionexhibitsa non-linear

segment priorto thetheoreticalyielding,Fig.3.5. Thiswouldhave important implicationson

the
exuralandaxialstrengthof beamsandcolumns.