Upload
donga
View
229
Download
3
Embed Size (px)
Citation preview
http://www.iaeme.com/IJCIET/index.asp 1050 [email protected]
International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 10, October 2017, pp. 1050–1063, Article ID: IJCIET_08_10_109
Available online at http://http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=8&IType=10
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication Scopus Indexed
DYNAMIC LATERAL EARTH PRESSURES ON
BASEMENT WALLS INDUCED BY HARMONIC
GROUND MOTIONS
Widjojo A. Prakoso
Civil Engineering Department
Universitas Indonesia, Depok, Indonesia
Rustama Berangket
Civil Engineering Department
Universitas Indonesia, Depok, Indonesia
Feny Yuzanda
Civil Engineering Department
Universitas Indonesia, Depok, Indonesia
ABSTRACT
In recent years, a number of publications on dynamic lateral earth pressures
acting on basement walls induced by seismic ground motions has appeared due to
good performance of basement walls during relatively large earthquakes. The main
concern is whether the current methods would provide excessively conservative lateral
earth pressures. In this paper, the 2-D plane strain dynamic finite element models
were used to examine the lateral earth pressures acting on 2-story concrete basement
walls. The seismic ground motions were constant-peak, harmonic ground motions;
three different peak acceleration values were considered. The Mohr-Coulomb
constitutive soil model was used in the analyses to represent a sands deposit. The
observed parameters were the horizontal wall acceleration, the lateral earth pressures
and their changes, and the lateral total thrusts (PAE). The overall results showed the
complex nature of the dynamic soil-structure interaction of basement structures. Some
of the findings include the effect of limiting soil tensile strength on the envelope of
change in lateral earth pressures (∆pAE), the non-linear increase in and complex
distribution of ∆pAE with an increase in the peak input acceleration, highly non-linear
relationship between PAE and wall acceleration, a discussion on phase difference, and
the effect of the embedment wall depths.
Keywords: Basement, Horizontal Acceleration, Lateral Earth Pressure, Dynamic Finite
Element.
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground Motions
http://www.iaeme.com/IJCIET/index.asp 1051 [email protected]
Cite this Article: Widjojo A. Prakoso, Rustama Berangket and Feny Yuzanda,
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground
Motions, International Journal of Civil Engineering and Technology, 8(10), 2017,
pp. 1050–1063
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=10
1. INTRODUCTION
The Indonesia seismic building code [1] requires that basement walls be designed against the
increased lateral earth pressures associated with seismic ground motions. However, the code
does not specify any methods to estimate the increased pressures. In recent years at the
international level, this topic has attracted discussions due to good performance of basement
walls during relatively large earthquakes (e.g., [2, 3, 4, 5]). Many different design estimation
methods have been proposed in the literature (e.g., [4]). One of the concerns is whether the
typical estimation methods would yield in overly conservative the increased pressures.
These studies examined different factors affecting the increased dynamic lateral earth
pressures. As an example, Winner and Prakoso [5] examined the effects of seismic ground
motion parameters and soil constitutive models on the dynamic lateral earth pressures behind
basement wall and the wall bending moments; the basement structures considered had no
embedded walls. They found that the pressures and bending moments are dependent on the
peak value and frequency of the input acceleration. The pressures are also dependent on the
limiting soil tensile strength provided by the soil cohesion, but the bending moments are
relatively independent of the soil tensile strength.
The objective of this study is to identify the dynamic lateral earth pressures acting on
basement walls for different peak input acceleration and for different wall embedment depths.
For this paper, the seismic ground motions considered are synthetic, harmonic ground
motions with constant peak acceleration values. The basements considered is a 2-level, 8 m
deep basements typically constructed in Jakarta area; no pile foundations are considered in the
basement model. This paper describes the finite element model used and cases evaluated, as
well as the numerical results, particularly in terms of the lateral earth pressures and wall
acceleration
2. RESEARCH METHOD
The research method was to employ two-dimensional, finite element models to examine the
increased lateral earth pressures. The assumed geotechnical conditions were a 25 m thick
sands deposit overlying an engineering bedrock. The depth and width of the concrete
basement considered are 8 m and 18 m, respectively. The thickness of the basement concrete
wall is 0.6 m, while the embedment depths was varied from 4 m to 10 m (total wall length 12
m to 18 m).
The typical 2-D plane strain finite element model is shown in Figure 1. Fifteen-node
triangular finite elements were used to model the soils, and concrete walls; the number of
elements was 1,018 elements. Much finer elements were used for the basement walls and the
soil directly behind the walls in order capture the increased pressures and bending moments
(See Figure 1.). Beam elements were used to model the basement structural elements (e.g.,
columns and beams).
The constitutive soil model used for all the soil elements was the Mohr-Coulomb
constitutive soil model. The soil was assumed to be medium sands, and the properties were
adapted from [6] for convenient model verification purposes. The soil properties are given in
Table 1. The constitutive model used for the basement wall elements was the elastic model;
the properties are given in Table 2. The structural elements were assumed to remain elastic
Widjojo A. Prakoso, Rustama Berangket and Feny Yuzanda
http://www.iaeme.com/IJCIET/index.asp 1052 [email protected]
throughout the analyses; the properties of these elements are given in Table 3. Interface
elements were used between the soil elements and the wall elements. Absorbent boundaries
were specified for the sides to avoid spurious reflection during dynamic analyses. The
damping used was the Rayleigh damping model with factors of α = 0 and β = 0.0022,
representing a damping ratio of about 5% [7]. The geotechnical finite element software used
was Plaxis 2-D version 8 [8].
The input seismic motion reported in this paper was a constant frequency, constant
amplitude harmonic acceleration. The harmonic acceleration was 3 Hz and 4 second long (12
cycles). The range of the peak ground acceleration was varied from 0.2 g, 0.5 g, and 0.7 g.
The typical harmonic acceleration time history is shown in Figure 2. The acceleration was
applied using the prescribed displacement option at the base of the mesh. The dynamic
calculations were performed in 1,000 dynamic calculation steps (∆t = 0.004 s). The observed
outputs include the wall acceleration and bending moments, as well as the lateral earth
pressure behind wall. The dynamic calculation was performed after the static construction
stage (basement excavation, wall and structure installation).
Figure 1 Finite element mesh (top), wall and soil nodes (bottom-left), wall and soil stress points
(bottom-right)
Table 1 Soil properties
Soil Property Symbol Value Unit
Unit weight γ 17 kN/m3
Modulus E 40 MN/m2
Friction angle φ 35 degree
Cohesion C 0.2 kN/m2
Poisson’s ratio υ 0.33 -
Rinterface R 0.7 -
Table 2 Wall properties
Soil Property Symbol Value Unit
Unit weight γ 24 kN/m3
Modulus E 20 GN/m2
Thickness T 600 mm
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground Motions
http://www.iaeme.com/IJCIET/index.asp 1053 [email protected]
Table 3 Structural element properties
Soil Property Symbol Value Unit
Unit weight γ 24 kN/m3
Modulus E 20 GN/m2
Beam
dimensions
Bf 3500 mm
Bw 300 mm
H 600 mm
Spacing 6 m
Column
dimensions
B 400 mm
H 400 mm
Spacing 6 m
Figure 2 Typical input acceleration (3 Hz, 4 second long)
3. RESULTS
3.1. Model Verification
The model verification was conducted by checking the resulting static lateral earth pressures
(pA) and the resulting dynamic wall acceleration. The static pressures examined were the
pressures along the basement at the end of construction stage. Figure 3 shows the resulting
pressures, and also the Rankine active earth pressure line and the at-rest lateral earth pressure
line. These lines were determined based on the soil friction angle of 35°. It can be seen that
the resulting pressures at the upper wall part were about the same as the Rankine active line to
depth of about 4 m. The pressures then increased to about the same as the at-rest line at depth
of 4 m. Subsequently, the resulting pressures decreased to the Rankine active line at the wall
tip level.
The resulting dynamic wall acceleration is compared directly with the peak input
acceleration in Figure 4. For lower acceleration values, the wall acceleration was higher than
the input acceleration, indicating amplification of the ground motions. However for higher
values, the former became lower than the latter, indicating de-amplification of the ground
motions. The general trend shown is similar to that published in [6]. In addition, a dynamic
model verification for a soil retaining system has been given in [9].
-6
-4
-2
0
2
4
6
0 1 2 3 4
Inp
ut
Acc
ele
rati
on
(m
/s2)
Time (s)
Widjojo A. Prakoso, Rustama Berangket and Feny Yuzanda
http://www.iaeme.com/IJCIET/index.asp 1054 [email protected]
3.2. Basement Wall Acceleration
The time history of the horizontal basement wall acceleration for input acceleration = 0.2 g is
shown in Figure 5 (top), while that for input acceleration = 0.7 g is shown in Figure 5
(bottom). Three monitoring locations are considered: 0.67 m (about top floor slab level), 4.0
m (middle floor slab level), and 8.0 m (bottom floor slab level). In general, the absolute
values of maximum and minimum wall acceleration are relatively the same, following the
pattern of the input harmonic acceleration. The peak wall acceleration values were greater
than the peak input acceleration. The amplification factors could then be calculated as the
ratio of peak wall acceleration to peak input acceleration. Table 4 summarizes the
amplification factors at top and bottom floor slab levels. As expected, the amplification
factors at top floor slab level were greater than those at bottom floor slab level, and the factors
for input acceleration = 0.2 g were greater than those input acceleration = 0.7 g.
Figure 3 Static model verifications
Figure 4 Dynamic model verification
0
2
4
6
8
10
12
14
16
18
0 20 40 60 80 100 120
De
pth
(m
)
pA (kPa)
Basement Level
Emb. Depth = 4 m
Emb. Depth = 6 m
Emb. Depth = 8 m
Emb. Depth = 10 m
Active (Rankine)
At-Rest
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.2 0.4 0.6 0.8
Wa
ll A
cce
lera
tio
n (
g)
Input Acceleration (g)
Emb. Depth = 4 m
Emb. Depth = 6 m
Emb. Depth = 8 m
Emb. Depth = 10 m
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground Motions
http://www.iaeme.com/IJCIET/index.asp 1055 [email protected]
Table 4 Amplification factors
Depth (m) Input acc. = 0.2 g Input acc. = 0.2 g
0.67 2.845 1.697
8.00 1.934 1.445
The wall acceleration maximum value at depth of 8 m for input acceleration = 0.2 g was
about 3.5 m/s2, while that for input acceleration = 0.7 g was about 10 m/s
2. The increase in
wall acceleration appears not to be linearly proportional to the increase in the peak input
acceleration.
It is clear that there was a phase difference between the peaks of horizontal wall
acceleration; for example, the peak at depth of 8.0 m occurred first, followed subsequently by
that at depth of 4.0 m and 0.67 m. This suggests that, although it was of high stiffness (t = 0.6
m, supported by 3 levels of floor slabs), the basement did not act as a completely rigid body.
The time history of the horizontal wall acceleration (at bottom floor slab level, input
acceleration = 0.5 g) for basements with different wall lengths beneath the excavation level or
wall embedment depths (4 m, 6 m, 8 m, and 10 m) is shown in Figure 6. It can be seen that
the acceleration of walls with different embedment depths was relative similar to each other.
Therefore, it can be concluded that the embedment depths had a minor effect on the wall
acceleration.
Figure 5 Horizontal wall acceleration at different depths: Input acceleration 0.2g (top) and 0.7g
(bottom)
-15
-10
-5
0
5
10
15
0 1 2 3 4
Wal
l Acc
eler
atio
n (m
/s2 )
Time (s)
z=0.67m z=4.00m z=8.00m
-15
-10
-5
0
5
10
15
0 1 2 3 4
Wal
l Acc
eler
atio
n (m
/s2 )
Time (s)
z=0.67m z=4.00m z=8.00m
Widjojo A. Prakoso, Rustama Berangket and Feny Yuzanda
http://www.iaeme.com/IJCIET/index.asp 1056 [email protected]
Figure 6 Horizontal wall acceleration: Effect of wall embedment depths
3.3. Lateral Earth Pressures
The time history of the total dynamic lateral earth pressures (pAE) acting on the basement wall
for input acceleration = 0.2 g is shown in Figure 7 (top), while the corresponding time history
of change in lateral earth pressures (= total dynamic lateral earth pressure – static lateral earth
pressure, ∆pAE) is shown in Figure 7 (bottom). It is noted that a positive pressure is a
compressive pressure. Five monitoring locations are considered: 0.85 m (about ground surface
level), 1.8 m (about midway between top and middle floor slabs), 4.0 m (middle slab level),
6.2 m (about midway between middle and bottom floor slabs), and 7.9 (slightly above bottom
floor slab). In general, pAE and ∆pAE followed harmonic nature of the input acceleration time
history. In all observation points, pAE remained in compression. The envelope of ∆pAE was
relatively symmetrical (absolute values of maximum and minimum change in pressures
relatively the same).
The time history of pAE for input acceleration = 0.7 g is shown in Figure 8 (top), while
∆pAE is shown in Figure 8 (bottom). The minimum values of pAE were about zero due to
limited soil tensile strength, and the resulting ∆pAE was not symmetrical. This condition was
observed for relatively shallow stress points (0.85 m and 1.8 m). The difference in results for
input acceleration = 0.2 g and 0.7 g suggested that the general trend of ∆pAE would be
affected by the soil tensile strength.
-15
-10
-5
0
5
10
15
0 1 2 3 4
Wal
l Acc
eler
atio
n (m
/s2)
Time (s)
ED = 4 m ED = 6 m
ED = 8 m ED = 10 m
0
100
200
300
0 1 2 3 4
pA
E(k
N/m
2)
z=0.85m z=1.82m z=4m
z=6.18m z=7.92m
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground Motions
http://www.iaeme.com/IJCIET/index.asp 1057 [email protected]
Figure 7 Lateral earth pressure acting on basement wall (0.2g): Total pressure (top) and change in
pressure (bottom)
The maximum value of ∆pAE for input acceleration = 0.2 g was in the order of 45 kPa,
while that for input acceleration = 0.7 g was in the order of 135 kPa. The increase in ∆pAE
appears not to be linearly proportional to the increase in the peak input acceleration.
It is clear that there was a phase difference between the peaks of ∆pAE. For input
acceleration = 0.2 g, the first local peaks of ∆pAE for depths = 0.8 m and 1.8 m occurred at
slightly different times, but ∆pAE for depths = 4.0 m, 6.2 m, and 7.9 m decreased and reached
the local minimum values at slightly different times. A moment latter, the first local peaks of
∆pAE for depths = 4.0 m, 6.2 m, and 7.9 m occurred at slightly different times, but ∆pAE for
depths = 0.8 m and 1.8 m decreased and reached the local minimum values at slightly
different times. Nevertheless, the harmonic nature of pAE could clearly be seen. For input
acceleration = 0.7 g, a similar trend could be observed. However, the harmonic nature of pAE
and ∆pAE became less clearer.
The time history of ∆pAE (at middle floor slab level, input acceleration = 0.5 g) for
basements with different wall embedment depths is shown in Figure 9. It can be seen that
∆pAE of walls with different embedment depths was relative similar to each other, or in other
words, the embedment depths had a minor effect on ∆pAE.
-100
0
100
200
0 1 2 3 4
Δp
AE
(kN
/m2)
Time (s)
z=0.85m z=1.82m
z=4m z=6.18m
z=7.92m
0
100
200
300
pA
E(k
N/m
2)
z=0.85m z=1.82m
z=4m z=6.18m
z=7.92m
Widjojo A. Prakoso, Rustama Berangket and Feny Yuzanda
http://www.iaeme.com/IJCIET/index.asp 1058 [email protected]
Figure 8 Lateral earth pressure acting on basement wall (0.7g): Total pressure (top) and change in
pressure (bottom)
Figure 9 Change in lateral earth pressure: Effect of wall embedment depths
The distribution of ∆pAE with depth for five (5) conditions is shown as Figure 10 (top) for
input acceleration = 0.2 g. In the first and second conditions in which ∆pAE at depth = 0.8 m
and 1.8 m was maximum respectively, ∆pAE decreased with depth, and ∆pAE even became
negative. In the third through fifth conditions in which ∆pAE at depth = 4.0 m, 6.2 m, and 7.9
m was maximum respectively, ∆pAE was relatively uniform to depth of about 6 m, and it
increased with depth. The maximum ∆pAE values for all conditions were relatively the same.
The distribution of ∆pAE with depth for five (5) conditions is shown as Figure 10 (bottom)
for input acceleration = 0.7 g. In the first and second conditions, ∆pAE remained relatively
uniform to depth of about 2 m, then decreased with depth to depth of about 4 m, then
remained relatively uniform to depth of about 7 m, and finally increased. In the third through
fifth conditions, ∆pAE was relatively uniform to depth of about 3 m, and it increased with
depth. The maximum ∆pAE values for all conditions increased gradually from the first to the
fifth conditions. In addition, the use of ∆pAE envelope for both input acceleration values
would lead to a very conservative design.
-100
0
100
200
0 1 2 3 4
Δp
AE
(kN
/m2)
Time (s)
z=0.85m z=1.82m z=4m
z=6.18m z=7.92m
-100
0
100
200
0 1 2 3 4
∆∆ ∆∆p A
E(k
N/m
2 )
Time (s)
ED = 4 m ED = 6 m
ED = 8 m ED = 10 m
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground Motions
http://www.iaeme.com/IJCIET/index.asp 1059 [email protected]
For a given condition in Figure 10, the distribution with depth and maximum value of
∆pAE for input acceleration = 0.2 g were not linearly proportional to those for input
acceleration = 0.7 g. For the first condition, the distribution of ∆pAE could be negative in the
lower wall part for 0.2 g case, but that for 0.7 g case was all positive. For the third condition,
the distribution of ∆pAE decreased in the upper wall part, but increased in the lower wall part,
with an increase in peak input acceleration. For the fifth condition, the distribution of ∆pAE up
to depth of 3 m was relatively similar for both cases, but that below that depth was
significantly different.
3.4. Lateral Total Thrusts
The change in lateral earth pressures (∆pAE) can be subsequently integrated to obtain the
lateral total thrusts (PAE). The time history of PAE can also be obtained. Figure 11 (top) shows
the time history of PAE for input acceleration = 0.2 g, while Figure 11 (bottom) shows that for
input acceleration = 0.7 g. The harmonic nature of PAE could clearly be seen. For the
considered cases, the dynamic thrust appears to be stable after time about 2 seconds. For input
acceleration = 0.2 g, the maximum and minimum PAE values in the stable time period were
about 200 to 250 kN/m and 50 to 100 kN/m, respectively. For input acceleration = 0.7 g, the
maximum and minimum PAE values in the stable time period were about 500 to 550 kN/m and
200 to 250 kN/m, respectively. The increase in maximum and minimum PAE values, as well in
the increase in difference between the maximum and minimum PAE values, appear not to be
linearly proportional to the increase in the peak input acceleration.
0
1
2
3
4
5
6
7
8
-40 0 40 80 120 160
De
pth
(m
)
∆∆∆∆pAE (kN/m2)
z = 0.85 m (t = 1.016 s)
z = 1.82 m (t = 3.691 s)
z = 4.00 m (t = 1.880 s)
z = 6.18 m (t = 2.562 s)
z = 7.92 m (t = 1.900 s)
Widjojo A. Prakoso, Rustama Berangket and Feny Yuzanda
http://www.iaeme.com/IJCIET/index.asp 1060 [email protected]
Figure 10 Distribution of lateral earth pressure with depth for five conditions: Input acceleration 0.2g
(top) and 0.7g (bottom)
Figure 11 Lateral total thrusts: Input acceleration 0.2g (top) and 0.7g (bottom)
0
1
2
3
4
5
6
7
8
-40 0 40 80 120 160
De
pth
(m
)
∆∆∆∆pAE (kN/m2)
z = 0.85 m
(t = 0.976 s)
z = 1.82 m
(t = 1.952 s)
z = 4.00 m
(t = 3.498 s)
z = 6.18 m
(t = 3.855 s)
z = 7.92 m
(t = 3.867 s)
-200
0
200
400
600
0 1 2 3 4
PA
E(k
N/m
)
-200
0
200
400
600
0 1 2 3 4
PA
E(k
N/m
)
Time (s)
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground Motions
http://www.iaeme.com/IJCIET/index.asp 1061 [email protected]
4. DISCUSSIONS
The absolute values of maximum and minimum wall acceleration were relatively the same in
each case of input acceleration = 0.2 g and 0.7 g, following the pattern of the input harmonic
acceleration. The peak wall acceleration values were greater than the peak input acceleration.
The amplification factors (= peak wall acceleration / peak input acceleration) at top floor slab
level were greater than those at bottom floor slab level. The factors for input acceleration =
0.2 g were greater than those input acceleration = 0.7 g, consistent with outputs from other
soil retaining system studies [e.g., 6].
The time histories of change in lateral earth pressures (∆pAE) for both input acceleration =
0.2 g and 0.7 g had different characteristics. The envelope of ∆pAE for the former was
relatively symmetrical, while that for the latter was not symmetrical due to the minimum
values of pAE about zero due to the limiting soil tensile strength. This behavior is consistent
with the behavior observed in [5].
The distribution with depth and maximum value of ∆pAE were also examined. for input
acceleration = 0.2 g were not linearly proportional to those for input acceleration = 0.7 g. Not
only the values, the shape of the distribution with depth of ∆pAE varied considerably,
indicating a complex nature of the soil-structure interaction of basement structures.
Nevertheless, the use of ∆pAE envelope for both input acceleration values would lead to a very
conservative design.
Figure 12 Relationship between total thrust and wall horizontal acceleration: Input acceleration 0.2g
(top) and 0.7g (bottom)
-100
0
100
200
300
400
500
600
-8 -6 -4 -2 0 2 4 6 8
Tota
l Th
rust
(kN
/m)
Wall Acceleration @ 4 m (m/s2)
-100
0
100
200
300
400
500
600
-8 -6 -4 -2 0 2 4 6 8
Tota
l Th
rust
(k
N/m
)
Wall Acceleration @ 4 m (m/s2)
Widjojo A. Prakoso, Rustama Berangket and Feny Yuzanda
http://www.iaeme.com/IJCIET/index.asp 1062 [email protected]
The lateral total thrusts (PAE) could be examined against the horizontal wall acceleration.
Figure 12 shows PAE taken from Figure 11 and wall acceleration taken from Figure 5. For the
stable time period after 2 seconds, the relationship between PAE and wall acceleration is
highly non-linear for both input acceleration = 0.2 g and 0.7 g, although the latter appears to
be at a higher complexity level. A negative wall acceleration (to left of the model) caused the
maximum PAE, while the positive acceleration caused the minimum PAE in the stable time
period. This behavior emphasizes the complex nature of the soil-structure interaction of
basement structures.
It was observed that there was a phase difference between the peaks of horizontal wall
acceleration at different depths. Furthermore, it was also observed that there was a phase
difference between the peaks of ∆pAE. At certain depths, the difference could be significant,
an increase in ∆pAE at a certain depth accompanied with a decrease in ∆pAE at a different
depth and vice versa. This phase difference was clear, although the wall had a relatively high
stiffness (t = 0.6 m, supported by 3 levels of floor slabs). The harmonic time history pattern of
∆pAE became less apparent for a higher peak input acceleration, possibly due to the soil linear
behavior. This phase difference was also observed in centrifuge test results [10] and other
numerical simulations [6]. Nevertheless, the relationship between PAE and wall acceleration
suggests that the phase difference might not be of great importance in the overall behavior.
The time history of the horizontal wall acceleration and that of ∆pAE for basements with
different wall lengths beneath the excavation level or wall embedment depths (4 m, 6 m, 8 m,
and 10 m) were shown in Figures 4 and 9. In both figures, the acceleration and ∆pAE of walls
with different embedment depths were relative similar to each other. Therefore, it can be
concluded that the embedment depths had a minor effect on the wall acceleration and ∆pAE.
5. CONCLUSIONS
The absolute values of maximum and minimum wall acceleration were relatively the same in
each case of input acceleration = 0.2 g and 0.7 g, following the pattern of the input harmonic
acceleration. The peak wall acceleration values were greater than the peak input acceleration.
The amplification factors (= peak wall acceleration / peak input acceleration) at top floor slab
level were greater than those at bottom floor slab level. The factors for input acceleration =
0.2 g were greater than those input acceleration = 0.7 g, consistent with outputs from other
soil retaining system studies [e.g., 6 The 2-D plane strain dynamic finite element models were
used to examine the lateral earth pressures on 2-story basement walls induced by constant
peak value, harmonic ground motions. The soil constitutive model used was the Mohr-
Coulomb model with very limited tensile strength to represent a sands deposit. Four different
embedment wall depths were also considered. The overall results showed the complex nature
of the dynamic soil-structure interaction of basement structures. Some highlighted qualitative
points are as follows:
• The envelope of ∆pAE was dependent on the peak input acceleration due to the
limiting soil tensile strength.
• The increase in horizontal wall acceleration, ∆pAE, and PAE appeared not to be
linearly proportional to the increase in the peak input acceleration.
• The relationship between PAE and wall acceleration was highly non-linear, and the
complexity appears to increase with a higher input acceleration.
• A phase difference was observed in horizontal wall acceleration and ∆pAE.
• The embedment wall depths had a minor effect on the wall acceleration and ∆pAE.
Dynamic Lateral Earth Pressures on Basement Walls Induced by Harmonic Ground Motions
http://www.iaeme.com/IJCIET/index.asp 1063 [email protected]
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the partial support from the 2017 PITTA research grant
provided by Universitas Indonesia.
REFERENCES
[1] Badan Standarisasi Nasional (BSN). Tata cara perencanaan ketahanan gempa untuk
struktur bangunan gedung dan non gedung (Indonesia seismic resistance building code),
2012. (in Indonesian)
[2] M. Lew, N. Sitar, L. Al-Atik, M. Pourzanjani and M.B. Hudson, Seismic earth pressures
on deep building basements, SEAOC 2010 Convention, 2010.
[3] M. Taiebat, E. Amirzehni and W.D.I. Finn, Seismic design of basement walls: evaluation
of current practice in British Columbia, Canadian Geotechnical Journal, 51, 2014, pp.
1004-1020.
[4] N. Sitar and N. Wagner, On seismic response of stiff and flexible retaining structures, 6th
International Conference on Earthquake Geotechnical Engineering, 2015.
[5] A.B. Winner and W.A. Prakoso, Behavior of basement wall subjected to synthetic
harmonic ground motions, 3rd International Conference on Earthquake Engineering and
Disaster Mitigation, 2016.
[6] A. Athanasopoulos-Zekkos, V.S. Vlachakis and G.A. Athanasopoulos, Phasing issues in
the seismic response of yielding, gravity-type earth retaining walls – Overview and results
from a FEM study, Soil Dynamics and Earthquake Engineering, 55, 2013, pp. 59-70.
[7] E. Guler, E. Cicek, M.M. Demirkan and M. Hamderi, Numerical analysis of reinforced
soil walls with cohesive and granular backfills under cyclic loads, Bulletin of Earthquake
Engineering, 10, 2012, pp. 793-811.
[8] Plaxis B.V. Plaxis 2D – Version 8, A.A. Balkema Publishers, 2002.
[9] W.A Prakoso and H. Kurniawan, Seismic Amplification of Double-Sided Geosynthetic-
Reinforced Soil Retaining Walls, 6th International Conference on Earthquake
Geotechnical Engineering, 2015.
[10] S. Nakamura, Reexamination of Mononobe-Okabe theory of gravity retaining walls using
centrifuge model tests, Soil and Foundations, Vol. 46 pp. 135-146, 2006.
[11] A.S. Vijay Vikram and Dr. S. Arivalagan, A Short Review on the Sugarcane Bagasse with
Sintered Earth Blocks of Fiber Reinforced Concrete, International Journal of Civil
Engineering and Technology (IJCIET) Volume 8, Issue 6, June 2017, pp. 323-331.