Civil Engineering Reference
In-Depth Information
The lateral earth pressure diagrams for the 3 and 10-bay frames are those found
at the end of the last expansion cycle. The magnitude of the pressure developed
behind the 3-bay RFERS is similar to the load stipulated by ASCE 7-98, while the
pressure found behind the 10-bay frame is more than 20% larger than the lateral
earth pressure at rest.
The bending moment diagrams for the retaining wall portion of the 3 and 10-
bay RFERS are shown in Fig. 9.32 and 9.45 for the initial backfill stage and the
last expansion cycle, respectively. A substantial increase in the moment magnitude
is found for both frames due to thermal movements.
The bending moment at the first frame level of the 3-bay RFERS is shown to
increase nearly 800% at the end of the last expansion cycle, while its counterpart
for the 10-bay frame was nearly 20 times larger due to thermal expansion.
30
M
bn3
M
bn10
25
20
15
L
b
= 20 ft
φ
10
= 30
o
5
S
c
/S
b
= 4
0
-20
-10
0
10
20
30
Retaining Wall Moment, M, kips-ft
Fig. 9.32
Retaining Wall Moment at Backfill Stage (φ = 30º, All Bays, L
b
=20 ft, S
c
/S
b
= 4)
30
M
en3
M
en10
25
20
15
L
b
= 20 ft
φ
10
= 30
o
5
S
c
/S
b
= 4
0
-20
-10
0
10
20
30
Retaining Wall Moment, M, kips-ft
Fig. 9.33
Retaining Wall Moment at Expansion Cycle (φ = 30º, All Bays, L
b
= 20 ft,
S
c
/S
b
= 4)
