Civil Engineering Reference
In-Depth Information
Both yielding and stability effects must be considered when
σ
a
/F
a
0.15. AREMA
(2008) recommends that, when
0.15, Equation 8.70 (yield criterion)
extended for biaxial bending and Equation 8.76 (stability criterion) should be used
for design as
σ
a
/F
a
0.55
F
y
+
σ
b
x
σ
a
F
b
x
+
σ
b
y
F
b
y
≤
1.0
(8.79)
and
σ
a
F
a
+
σ
b
x
F
b
x
1
−
σ
a
/
0.514
2
E
(K
x
L
x
/r
x
)
2
π
σ
b
y
+
F
b
y
1
2
E
K
y
L
y
/r
y
2
≤
1.0,
(8.80)
−
σ
a
/
0.514
π
where
σ
a
is the normal axial compressive stress,
σ
b
x
is the normal flexural stress
about the
x
axis,
σ
b
y
is the normal flexural stress about the
y
axis,
F
a
is the allowable
axial compressive stress for axial compression only (Chapter 6),
F
b
x
is the allowable
flexural compressive stress for bending only (Chapter 7) about the
x
axis, and
F
b
y
is the allowable flexural compressive stress for bending only (Chapter 7) about the
y
axis.
Equation 8.79 relates to the yield criterion, which is appropriate to consider at
support locations, members with very low slenderness ratios, and locations braced in
the planes(s) of bending. The design of members subjected to axial compression and
bending is usually governed by the stability criterion of Equation 8.80.
8.5 COMBINED BENDING AND SHEAR OF PLATES
Combinedbendingandshearmaybesignificantinthewebsofplategirdersasoutlined
in Chapter 7, Section 7.2.6, concerning the plate girder design.
REFERENCES
American Railway Engineering and Maintenance-of-Way Association (AREMA), 2008, Steel
structures, in
Manual for Railway Engineering
, Chapter 15, Lanham, MD.
Beyer, W.H. (Ed.), 1984,
Standard Mathematical Tables
, 27th Edition, CRC Press,
Boca Raton, FL.
Birnstiel, C., 1968, Experiments on H-columns under biaxial bending,
Journal of Structural
Engineering
, ASCE, (94), ST10, 2429-2450.
Bresler, B., Lin, T.Y., and Scalzi, J.B., 1968,
Design of Steel Structures
, 2nd Edition, Wiley,
NewYork.
Chen, W.F. and Astuta, T., 1977,
Theory of Beam Columns
, Vols 1 and 2, McGraw-Hill,
NewYork.
Chen, W.F. and Lui, E.M., 1987,
Structural Stability
, Elsevier, NewYork.
Culver, C.G., 1966, Exact solution of the biaxial bending equations,
Journal of Structural
Engineering
, ASCE, (92), ST2, 63-84.
Galambos,T.V.,1988,
GuidetoStabilityDesignCriteriaforMetalStructures
,Wiley,NewYork.
