Civil Engineering Reference
In-Depth Information
30
25
20
15
L
b
= 20 ft
φ
U
hen1
U
hen3
U
hen10
10
= 30
o
5
S
c
/S
b
= 1
0
0
0.2
0.4
0.6
0.8
1
Horizontal End Column Movement, U
h
, ft
Fig. 9.26
End Column Movements at Expansion Cycle (φ = 30º, All Bays, L
b
= 20 ft,
S
c
/S
b
= 1)
The horizontal deflection of the end column of the 3-bay frame, on the other
hand, is found to increase by nearly 10% due to thermal expansion movements,
while the horizontal deflection of its counterpart of the 10-bay frame is found to
nearly double at the end of the last expansion cycle. By comparing the horizontal
movements of the retaining wall portion of the three RFERS shown in Fig. 9.20
and 9.21 to the end column movements, it is apparent that the entire potential
thermal expansion strains of all three frames occur at the free end, in the direction
away from the soil mass.
The bending moment diagrams of the end column at the initial backfill stage
and the last expansion cycle are shown in Fig. 9.27 and 9.28, respectively.
The magnitude of the bending moments is found to increase at the end of the
last expansion cycle, particularly at the first and second frame levels. The relative
increase in moment magnitude is found to be largest for 10-bay frame, and
smallest for the single bay frame.
30
M
bn1
M
bn3
M
bn10
25
20
15
L
b
= 20 ft
φ
10
= 30
o
5
S
c
/S
b
= 1
0
-20
-10
0
10
20
30
End Column Moment, M, kips-ft
Fig. 9.27
End Column Moment at Backfill Cycle (
φ
= 30º, All Bays, L
b
= 20 ft, S
c
/S
b
= 1)
