Civil Engineering Reference
In-Depth Information
The pressure is subsequently found to be larger behind the remainder of the
RFERS, increasing in magnitude with the increase in frame length and number of
bays. The 10-bay frame is found to retain a pressure slightly smaller than the earth
pressure at rest, while the pressure behind the 15-bay frame is found to be slightly
larger. The magnitude of the lateral earth pressure developed behind the 20-bay
frame, on the other hand, is more than twice the Coulomb's active earth pressure,
and nearly 30% higher than the lateral earth pressure at rest. The pressures behind
these 3 frames are also larger than their counterparts presented latterly.
The retaining wall bending moments found at the end of the initial backfill
stage and the last expansion cycle are shown in Fig. 9.14 and 9.15, respectively.
30
L
b
= 10 ft
φ
= 30
o
M
bn1
M
bn3
M
bn6
M
bn10
M
bn15
M
bn20
25
20
S
c
/S
b
= 4
15
10
5
0
-40
-30
-20
-10
0
10
20
30
40
Retaining Wall Moment, M, kips-ft
Fig. 9.14
Retaining Wall Moment at Backfill Stage (φ = 30º, All Bays, L
b
=10 ft, S
c
/S
b
= 4)
30
L
b
= 10 ft
φ
M
en1
M
en3
M
en6
M
en10
M
en15
M
en20
25
= 30
o
20
S
c
/S
b
= 4
15
10
5
0
-40
-30
-20
-10
0
10
20
30
40
Retaining Wall Moment, M, kips-ft
Fig. 9.15
Retaining Wall Moment at Expansion Cycle (
φ
= 30º, All Bays, L
b
=10 ft, S
c
/S
b
= 4)
The magnitude of the bending moment in the retaining wall portion of the
single, 3 and 6-bay frames are found to vary slightly between the two stages of
analysis, with the larger variation obtained for the frames with the larger number
of bays. The bending moments at the first frames level of the 10, 15 and 20-bay
