Civil Engineering Reference
In-Depth Information
Similar results were found for frames with bay lengths of 20 feet. Fig.7.16
illustrates the lateral earth pressure obtained from the analysis of 5 frames. The
results for the rigid frame with a single bay and a column to beam stifness ratio of
1 are not shown given that the numerical calculation could not be completed due
to the collapse of the soil body.
7.2.5 Four-Story Rigidly Framed Earth Retaining Structures
7.2.5.1 Backfill Soil with 30º Internal Friction Angle
The analysis results of four-story rigid frames are presented herein. Fig.7.17 below
illustrates the lateral earth pressure developed behind frames with bay length of 10
feet. The analysis results shown are consistent with their counterpart discussed
earlier for three-story frames, where the lateral earth pressure developed behind
the frames with lower lateral stiffness is found to be inline with the Coulomb
active earth pressure, while the earth pressure developed behind the stiffer frames
was more comparable to the slightly larger soil load stipulated by ASCE 7-98. In
all cases, however, the lateral earth pressure found from the analysis was
substantially smaller than the lateral earth pressure at rest.
40
σ
hn1
σ
hn3
σ
hn6
σ
hn10
σ
hn15
σ
hn20
Coulomb
35
30
ASCE 7-98
BOCA, SBC, IBC
25
20
L
b
= 10 ft
φ
K
0
15
= 30
o
10
S
c
/S
b
= 1
5
0
40
σ
hn1
σ
hn3
σ
hn6
σ
hn10
σ
hn15
σ
hn20
Coulomb
35
30
ASCE 7-98
25
BOCA, SBC, IBC
K
0
20
L
b
= 10 ft
φ
15
= 30
o
10
S
c
/S
b
= 4
5
0
0
0.5
1
1.5
2
2.5
3
σ
h
, kips/ft
2
Fig. 7.17
Lateral Earth Pressure behind Four Story Frames (
L
b
= 10 ft, φ = 30º)
