Civil Engineering Reference
In-Depth Information
43′ 4″
40′ 0″
3′ 0″
4 5pa.
θ 9′ 4″ = 37′ 4″
(a)
Transverse section
3 1/2″
3 1/2″
W
10″
1′ 7″
(b)
Section through semi-integral abutment
Figure 16.6
(a, b) Sample design of a semi
-
integral abutment.
Beam/girder spacing along the skew can be calculated with
S
Beam
cos 30
L
=
(16.1b)
°
With beam spacing
S
= 2.84 m (9.33′) and bridge skew angle of 30°,
L
= 3.28 m (10.77′).
Then, by assuming continuous beam along the abutment with supports
at girder lines, the moments, shears, and reaction under triangular earth
pressure can be calculated as
2
(
)(
)
2
Max positive moment
:
M
pos
=
0 08
.
wl
=
0 08 11 6
.
.
klf
10 77
.
ft
(
)
=
107 6
.
ft-kip
145 9
.
kN-m
2
(
)(
)
2
Max negative moment
:
M
neg
=
0 10
.
wl
=
0 10 11 6
.
.
klf
10 77
.
ft
(
)
=
134 6
.
ft-kip
182 5
.
kN-m
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