Civil Engineering Reference
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2
qL
L
L
8
(a) Simply supported beam-column
(b) Propped cantilever
q
q
N
L
L
(c) Continuous beam-column
Figure 7.20
Examples 6-8.
7.8.3 Example 8 - non-linear analysis
Analyse the non-linear elastic in-plane bending of the two-span beam-column
showninFigure7.20c,andshowthatthemaximummoment
M
max
maybeclosely
approximated by using
qL
2
/
8
≈
(
1
−
0.18
N
/
N
cr
,
y
)
M
max
(
1
−
0.49
N
/
N
cr
,
y
)
while
N
≤
N
cr
,
y
, in which
N
cr
,
y
=
π
2
EI
y
/
L
2
.
7.8.4 Example 9 - in-plane design
A7.0 m long simply supported beam-column, which is prevented from swaying
and from deflecting out of the plane of bending, is required to support a factored
designaxialloadof1200kNandfactoreddesignendmomentsof300and150kNm
which bend the beam-column in single curvature about the major axis. Design a
suitable UB or UC beam-column of S275 steel.
7.8.5Example 10 - out-of-plane design
The intermediate restraints of the beam-column of example 9 which prevent
deflection out of the plane of bending are removed. Design a suitable UB or
UC beam-column of S275 steel.
7.8.6 Example 11 - biaxial bending design
The beam-column of example 10 has to carry additional factored design end
moments of 75 and 75 kNm which cause double curvature bending about the
minor axis. Design a suitable UB or UC beam-column of S275 steel.
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