Page 25 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

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PROPERTIES OF STRUCTURAL STEELS AND EFFECTS OF STEELMAKING AND FABRICATION

STRUCTURAL STEELS, STEELMAKING, AND FABRICATION 1.23

FIGURE 1.12 Typical residual-stress distributions (+ indicates tension and − compression).

When loads are applied to structural members, the presence of residual stresses usually causes
some premature inelastic action; that is, yielding occurs in localized portions before the nominal
stress reaches the yield point. Because of the ductility of steel, the effect on strength of tension mem-
bers is not usually significant, but excessive tensile residual stresses, in combination with other con-
ditions, can cause fracture. In compression members, residual stresses decrease the buckling load
from that of an ideal or perfect member. However, current design criteria in general use for com-
pression members account for the influence of residual stress.
In bending members that have residual stresses, a small inelastic deflection of insignificant mag-
nitude may occur with the first application of load. However, under subsequent loads of the same
magnitude, the behavior is elastic. Furthermore, in “compact” bending members, the presence of
residual stresses has no effect on the ultimate moment (plastic moment). Consequently, in the design
of statically loaded members, it is not usually necessary to consider residual stresses.

1.15 LAMELLAR TEARING

In a structural steel member subjected to tension, elongation and reduction of area in sections normal
to the stress are usually much lower in the through-thickness direction than in the planar direction.
This inherent directionality is of small consequence in many applications, but it does become important
in design and fabrication of structures with highly restrained joints because of the possibility of

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