1. EXPERIMENTALAND ANALYTICAL STUDY ON
UPLIFT CAPACITY OF HORIZONTAL PLATE
ANCHOR EMBEDDED IN GEO-REINFORCED SAND
GUIDED BY:
PROF. S.P. PARMAR
1
Department of Civil Engineering
DHARMSINH DESAI UNIVERSITY
NADIAD – 387001
APRIL - 2019
PRESENTED BY:-
AKBARHUSAIN B.
(MG-008)
2. CONTENTS
Introduction
General
Objective and scope
Theoretical Background
Aim of the thesis
Literature reviews
Methodology
Results and Discussion
Conclusion and Future scope
References
2
3. INTRODUCTION
Anchors are primarily designed and
constructed to resist outwardly directed
loads imposed on the foundation of a
structure.
These outwardly directed loads are
transmitted to the soil at a greater depth
by the anchors.
3
Ground Anchors
4. Anchors are also used for tieback
resistance of earth-retaining
structures, waterfront structures, at
bends in pressure pipelines.
Each anchors of various types are
now used for uplift resistance of
transmission towers, utility poles,
aircraft, moorings, submerged
pipelines, and tunnels.
4
5. Why Reinforced Sand ?
To improve the uplift capacity of plate anchors.
To enable them to withstand higher stresses and to improve the basic properties of the
foundation material.
The basic mechanism of soil reinforcement
involves generation of frictional between
soil and reinforcement.
Advantages of soil reinforcement such as
Cost saving, increased stability,
easily available, easy handling and storage.
5
6. Objective and Scope
The main objective of the study is to find out the variation in uplift capacity of
plate anchor in poorly graded sand at different relative density and different
embedment ratio.
Also check the pullout capacity of anchor plate with and without use of
geosynthetics.
Check the experimental and analytical different in uplift capacity at different
reinforcement location.
Observe Load-displacement curve relationship.
Embedment depth of anchor plate is 0.3m, 0.45m, 0.6m from top.
6
7. Experimental pullout test is performed on two different densities..
1) Dense 2) Very Dense
To achieve field condition in laboratory, plexiglass tank of 1.2m * 1.2m * 1.2m
size is arranged.
Geonets will put on different position to optimize location of geosynthetics.
After collected Sand sample, To classify these sand sample property, necessary
tests are performed like Grain size distribution test, Specific gravity test,
Relative Index test & Direct shear test.
7
8. Experimental setup for Pull-out Test
8
Plexiglass tank [1.2m * 1.2m * 1.2m size] Arrangement of proving ring and Dial Gauge
9. THEORETICAL BACKGROUND
Anchor plate may be made of steel plates, precast concrete slabs, poured Concrete
slabs, timber sheets, and so forth.
Horizontal anchor plate resist vertically-directed uplifting load.
Inclined plate resist axial pull-out load.
Vertical plate resist horizontally-directed pull-out load.
9
HORIZONTAL INCLINED VERTICAL
11. According to SHAPE:-
According to APPLICATION:-
11
1.CIRCULAR
2.SQUARE
3.RECTANGUALR
A.HORIZONTAL
B.INCLINED
C.VERTICAL
12. AIM OF THE THESIS
Find out the Best location of reinforcement for enhancing the maximum uplift
capacity of plate anchors.
To check the Effect of geosynthetics inclusion on the uplift behavior of plate
anchors.
The effect of Soil density and Embedment depth.
Load-displacement curve relationship.
Comparison of predicted pullout capacity with experimental pullout capacity.
To conduct laboratory tests to obtain soil parameters used in the analysis.
12
13. LITERATURE REVIEWS
PAPER NO. 1.
TITLE Uplift Behaviour Of Horizontal Plate Anchors Embedded
In Geocell-reinforced Sand
AUTHORS A.K.CHOUDHARY, S.K.DASH
PUBLICATION,
YEAR,
VOLUME.
Indian Geotechnical Conference
December 22-24,2013, Roorkee
13
15. It is observed that the ultimate uplift capacity with unreinforced sand is 25.98
kPa, whereas with geocell reinforcement it is 42.4 kPa, 43.1 kPa, and 44 kPa; for
the cases of b/B = 2, b/B = 3, and b/B = 4 respectively.
Tests results indicate that geocell reinforcement increases the uplift capacity of
plate anchors in the order of 1.7 times than that of the unreinforced sand.
However, with provision of an additional layer of planar geogrid right under the
geocell mattresses significantly improves the performance of the plate anchors
both in terms of increased uplift capacity and sustained deformations.
The increase in the uplift capacity of the plate anchor with the combined
application of geocell-planar reinforcement is in order of 2.28 times than that of
the unreinforced case.
15
16. PAPER NO. 2.
TITLE Uplift Behavior Of Plate Anchor With Geosynthetics
AUTHORS N.R. KRISHNASWAMY & S.P. PARASHAR
PUBLICATION,
YEAR,
VOLUME.
Geotechnical Engineering Division, Department Of
Civil Engineering, Indian Institute Of Technology,
Madras (15 May 1993)
16
18. The present study is mainly concerned with the improvement in the uplift
capacity of anchors is in the cohesive and cohesionless soil media with
geosynthetic inclusions.
Two different depths of embedment ratios, Ze/B, 4 and 7.5, which under the
categories of shallow and deep anchors respectively, were tested.
The granular soil used in this investigation was a uniformly graded medium
sand and two types of geogrids and geotextiles were used in these
investigations and their property are presented respectively. Most of the tests
were conducted using a circular plate of 60-mm diameter.
The ultimate uplift capacity of anchors and footing can be increased
significantly by the use of geosynthetics. Introduction of additional layers in
the fill will not contribute to any further increase in the uplift capacity.
18
19. Previous Work Done
Test is performed on loose(35%), medium(60%) and dense
condition(80%) and Results of Laboratory test shows that as the
Embedment ratio & Relative density increases the Uplift load increase.
Meyerhof and Adam’s theory give nearer value of ultimate uplift load for
loose sand but it gives higher value of ultimate uplift load in medium
dense & dense condition of soil in compared with model test’s results in
laboratory.
19
1. “Experimental Study On Uplift Capacity Of Square Plate Anchor In
Sand At Different Relative Density And Embedment Ratio”
- Patel Parth R (2017)
20. The focus of these physical investigations is to include the load-displacement
relationship, variation of peak uplift load with changing embedment ratio and
variation of the break-out factor with the embedment ratio.
Total 18 No of Pullout tests were performed.
Using empirical formula of Meyerhof and Adam’s Theory for circular plate
anchor, Uplift capacity Qu and Nq are find out. Uplift capacity and breakout
factor which are obtained from analytical calculation by F.E.M using Plaxis
and experimental model tests will be compared.
20
2. “Experimental Study On Uplift Capacity Of Axisymmetric Plate Anchor
In Well Graded Sand At Different Relative Density And Embedment Ratio”
-Vivek Soni (2018)
22. LIST OF PULL-OUT TEST
SIZE OF
ANCHOR
PLATE
RELATIVE
DENSITY
EMBEDMENT
DEPTH (m)
GEO-REINFORCEMENT
LOCATION
0.15m *0.15m
70%
0.3
Without Reinforcement
Reinforcement At Top Of Anchor Plate
0.45
Reinforcement At 0.25B From Top Of The
Anchor Plate
85%
0.6 Reinforcement At 0.5B From Top Of The
Anchor Plate
22
23. PROPERTIES
OF
GEONETS
Sr No. Properties Value
1. Form Roll
2. Colour Black
3. Apparent opening size 20mm * 10 mm
4. Thickness of material
EN ISO- 9863
≥ 5 mm
5. Wide width Tensile
strength MD-EN ISO
10319
≥ 13.5 kN/m
23
24. 6. CBR Puncture Resistance- EN
ISO 12236
≥2.2 kN
7. Mass Per Unit Area-
EN ISO 9864
≥ 830 g/m2
8. In plane permeability
EN ISO 12958
Hydraulic gradient (i=1)
@100 kPa
@200 kPa
≥ 0.6 l/m.s
≥ 0.55 l/m.s
9. Price Rs. / Sq.m
24
PROPERTIES
OF
GEONETS
29. Results of Predicted Pullout Capacity
from Analytical calculation
29
1). WITHOUT REINFORCEMENT
74.97
192
405.16
98.82
262.23
548.73
0
100
200
300
400
500
600
0.15 0.3 0.45 0.6 0.75
Load
(kg)
Embedment Depth (m)
70% relative
density
85% relative
density
30. 30
2). REINFORCEMENT AT TOP OF THE ANCHOR PLATE
135.67
286.49
514.44
149.83
323.97
607.99
0
100
200
300
400
500
600
700
0.15 0.3 0.45 0.6 0.75
Load
(kg)
Embedment Depth (m)
70%
relative
density
85%
relative
density
31. 31
3). REINFORCEMENT AT 0.25B FROM TOP OF THE ANCHOR
PLATE
123.05
259.81
497.13
143.06
317.46
590.76
0
100
200
300
400
500
600
700
0.15 0.3 0.45 0.6 0.75
Load
(kg)
Embedment Depth (m)
70% relative
density
85% relative
density
32. 32
4). REINFORCEMENT AT 0.5B FROM TOP OF THE ANCHOR
PLATE
100.24
231.64
434.63
116.023
275.79
547.85
0
100
200
300
400
500
600
0.15 0.3 0.45 0.6 0.75
Load
(kg)
Embedment Depth (m)
70% relative
density
85% relative
density
33. EXPERIMENTAL RESULTS FROM
PULL-OUT TEST
33
0
20
40
60
80
100
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
0
50
100
150
200
250
300
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
Qu V/S Δ For Embedment Depth = 0.3m, Without
Reinforcement
Qu V/S Δ For Embedment Depth = 0.45m, Without
Reinforcement
34. 34
0
100
200
300
400
500
600
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
0
20
40
60
80
100
120
140
160
180
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0.22 0.24 0.26 0.28
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70%Rd 85% Rd
Qu V/S Δ For Embedment Depth = 0.6m, Without
Reinforcement
Qu V/S Δ For Embedment Depth = 0.3m,
Reinforcement At Top Of The Anchor Plate
35. 35
0
50
100
150
200
250
300
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
0
100
200
300
400
500
600
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
Qu V/S Δ For Embedment Depth = 0.6m,
Reinforcement At Top Of The Anchor Plate
Qu V/S Δ For Embedment Depth = 0.45m,
Reinforcement At Top Of The Anchor Plate
36. 36
0
20
40
60
80
100
120
140
160
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0.22 0.24
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
0
50
100
150
200
250
300
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
Qu V/S Δ For Embedment Depth = 0.3m, Reinforcement
At 0.25B From Top Of The Anchor Plate
Qu V/S Δ For Embedment Depth = 0.45m, Reinforcement
At 0.25B From Top Of The Anchor Plate
37. 37
0
100
200
300
400
500
600
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
0
20
40
60
80
100
120
140
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0.22
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
Qu V/S Δ For Embedment Depth = 0.6m, Reinforcement
At 0.25B From Top Of The Anchor Plate
Qu V/S Δ For Embedment Depth = 0.3m, Reinforcement
At 0.5B From Top Of The Anchor Plate
38. 38
0
50
100
150
200
250
300
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
0
100
200
300
400
500
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Load,
Kg
Displacement, cm
Qu v/s δ for different relative density
70% Rd 85% Rd
Qu V/S Δ For Embedment Depth = 0.6m, Reinforcement
At 0.5B From Top Of The Anchor Plate
Qu V/S Δ For Embedment Depth = 0.45m, Reinforcement
At 0.5B From Top Of The Anchor Plate
39. Load-Displacement For Different
Reinforcement Location
39
0
50
100
150
200
250
300
350
400
450
500
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
load,
kg
Displacement, cm
W/O Reinf. Rein. At top Rein. At 0.25B reinforcement at 0.5B
Load V/S Displacement
For Different
Reinforcement Location
At 70% Relative
Density
40. 40
0
100
200
300
400
500
600
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Load,
Kg
Displacement, cm
W/O Reinf. Rein. At top Rein.at 0.25B reinforcement at 0.5B
Load V/S Displacement
For Different
Reinforcement Location
At 85% Relative
Density
41. Load V/S Embedment Ratio At Different
Reinforcement Location
41
0
100
200
300
400
500
600
0.15 0.3 0.45 0.6 0.75
Load,
kg
Embedment ratio, m
LOAD v/s EMBEDMENT RATIO
W/O REIN. REIN. AT TOP REIN. AT 0.25B REIN. AT 0.5B
Analytical Uplift
Capacity Comparison
for 70% Relative
density
42. 42
0
100
200
300
400
500
600
700
0.15 0.3 0.45 0.6 0.75
Load,
kg
Embedment ratio, m
LOAD v/s EMBEDMENT RATIO
W/O REIN. REIN. AT TOP REIN. AT 0.25B REIN. AT 0.5B
Analytical Uplift
Capacity Comparison
for 85% Relative
density
43. 43
0
100
200
300
400
500
600
0.15 0.3 0.45 0.6 0.75
Load,
Kg
Embedment ratio, m
LOAD v/s EMBEDMENT RATIO
W/O REIN. REIN. AT TOP REIN. AT 0.25B REIN. AT 0.5B
0
100
200
300
400
500
600
0.15 0.3 0.45 0.6 0.75
Load,
Kg
Embedment ratio, m
LOAD v/s EMBEDMENT RATIO
W/O REIN. REIN. AT TOP REIN. AT 0.25B REIN. AT 0.5B
Experimental Uplift Capacity Comparison For 70%
Relative Density
Experimental Uplift Capacity Comparison For 85%
Relative Density
44. Predicted Pullout Capacity V/S Observed
Pull-out Capacity For Diff. Relative Density.
44
0
50
100
150
200
250
300
350
400
450
500
550
0 50 100 150 200 250 300 350 400 450 500 550
Observed
pull-out
capacity
(Kg)
Predicted pull-out capacity (Kg)
without
reinforcement
reinforcement at
the top of anchor
plate
rein. At 0.25B
from top of the
anchor plate
rein.at 0.5B from
top of the anchor
plate
Predicted Pull-out
Capacity v/s
Observed Pull-out
Capacity for
70%Rd
45. 45
0
50
100
150
200
250
300
350
400
450
500
550
600
0 50 100 150 200 250 300 350 400 450 500 550 600 650
Observed
pull-out
capacity
()Kg
Predicted pull-out capacity (Kg)
without
reinforcement
reinforcement at
the top of anchor
plate
rein. At 0.25B
from top of the
anchor plate
rein.at 0.5B from
top of the anchor
plate
Predicted Pull-out
Capacity v/s
Observed Pull-out
Capacity for
85%Rd
46. CONCLUSION The ultimate uplift capacity of plate
anchors can be increased significantly
by the use of geosynthetics.
Based on test results, it is observed that
using Geonets reinforcement, the uplift
carrying capacity of the square plate
anchor can be significantly increased
1.4 times than that of unreinforced
case.
Effect Of
Geosynthetics
Inclusion
46
47. Four different configurations of geosynthetic
inclusion, as shown in Fig., were employed during
model test to determine the optimum location of the
geosynthetic inclusion for achieving the maximum
increase in the uplift capacity.
The configuration illustrated by case 2 in Fig.,
where the geosynthetic inclusion was resting
directly on the top of the anchor plate, proved to be
the best location for achieving the maximum
increase in ultimate uplift capacity.
47
Optimum
Location Of
The
Geosynthetic
Inclusion
Reinforcement At Top Of The Anchor Plate
48. The increase in soil density results in a higher
ultimate uplift capacity of anchors both with
and without geosynthetic inclusion.
According to test results, the uplift capacity
of plate anchor increases with the increase in
embedment depth. This increase can be
explained that the thickness of homogenous
zone between anchor and soil surface is
efficient and the uplift capacity increase with
increase of thickness of this zone.
Displacement corresponding to peak uplift
load is higher in larger embedment ratio
compared with smaller embedment ratio.
48
Effect Of
Soil Density
And
Embedment
Ratio
49. Diameter of failure surface is
increased from unreinforced plate
anchor to reinforced plate anchor.
Inclusion of geosynthetic layer
increase the effective area of
anchorage. A clear and distinct
upheaval of soil observed during peak
resistance condition. Maximum
upheaval occurred near the shaft.
49
WITHOUT REINFORCEMENT WITH REINFORCEMENT
50. FUTURE
SCOPE
Vertical Pull-out test can be performed on
sand of different gradation in Dry condition
& Submerge condition.
The experimental pull-out test can also be
performed by keeping different types of
geosynthetic material like geocell, geotextile,
geogrid etc.
Model test should be performed with one or
more layer of geosynthetic reinforcement &
also performed with different size of
geosynthetic reinforcement.
50
51. PLAXIS (FEM based) software has also
feature to analysis uplift force in soil
medium, so comparison can be done with
FEM based software’s results and
experimental results.
Same as vertical Pull-out, Horizontal Pull-
out test can also be performed with some
additional arrangement.
A linear variable displacement
transducer(LVDT) can be placed at top of
the square plate anchor to measure the
vertical displacement and predict the
movement of the anchor plate.
51
52. 52
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Foundations, 18(2): 17- 24.
Indian Standard Institution (1967), “Indian Standard Code Of Practise For Design And
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Baleshwer Singh, Birjukumar Mistri (2011), “A Study On Load Capacity Of Horizontal And
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Reinforcement”. Indian Geotechnical Conference-2010, Geotrendz, December 16-18,2010.
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Plate Anchors in Well Graded Sand at Different Relative Density and Embedment Ratio, MTech Thesis.
53
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Geotechnical Journal, Vol.5, No.4, Pp.225-244.
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Existing Vertical Anchor Plate In Sand”, Computers And Geotechnics 33 (2006) 167–176.
Aparnna E M, Reethi V P (2016), “Influence Of Aggregate Filled Geocell Reinforcement On The
Uplift Capacity Of Anchor Plate”. International Journal Of Engineering Research & Technology,
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PAPER PUBLISHED of THE SAME WORK
Akbar Husain KB, SP Parmar (2021) Experimental and analytic study of the uplift capacity of a
horizontal plate anchor embedded in geo-reinforced sand, IGGEC-21, First Indian Geotechnical and
Geoenvironmental Engineering Conference, pp 1-16.
54