Civil Engineering Reference
In-Depth Information
b
n
b
e
b
e
or
3
n
t
z
t
f
t
w
Noncomposite
steel beam
Transformed
composite section
(a)
(b)
+
+
=
Fy
M
D
1
M
D
2
S
LT
M
AD
S
NC
S
ST
Steel beam
Composite
Composite
Combined stresses
b
e
3
n
b
e
n
(c)
Stages 1 and 2
Stage 3
Stage 4
Figure 7.1
(a-c) Steel section properties and their respective stress diagrams.
which was later adopted by AASHTO load and resistance factor design
(LRFD) specifications (2013), recommend that the full slab width half-
way between adjacent girders can be counted as the effective width for
the concrete slab. Calculation of the effective widths and their respective
section properties will be shown in the example of Section 7.3. For each
of the loading stages described earlier in this section, a distinct set of
section properties exists and must be used in their respective analyses to
properly ascertain design forces and deflections to evaluate strength and
serviceability criteria.
Steel I-girder can be made of rolled beams or welded plate girders. For
typical bridges, fabricators usually prefer rolled beams. Generally, rolled
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