Experimental and Micromechanical
Computational Study of Pile Foundations
Subjected to Liquefaction-Induced Lateral
Spreading - Task 1 (1g Tests)
S. Thevanayagam, UB
Research Progress – Year 1
Feb. 12, 2007, 2-4 pm; UB-VTC
PI: R. Dobry, co-PI’s: A. Elgamal, S. Thevanayagam, T. Abdoun, M. Zeghal
UB-NEES Lab: A. Reinhorn, M. Pitman, J. Hanley, SEESL-Staff
Tulane: Usama El Shamy
Students & Staff: UB (N. Ecemis, B. Raghudeep, Q. Chen) and RPI (J.
Ubilla, M. Gonzalez, V. Bennett, C. Medina, Hassan, Inthuorn)
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Structural Engineering and Earthquake Simulation Laboratory
Agenda

Level Ground Liquefaction Test – LG-0
Test Name (correction – Test in Nov.06 was LG-0; No LG-1 test done)
 Instrumentation & Specimen Preparation
 Sensor data Interpretation
 Draft Results – Discussion


Report Preparation Status – Test LG-0
Rough Draft completed
 Final - Due April 1, 07

Schedule

& Budget Status – Year 2
Sloping Ground, Single Pile, Group Pile
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Structural Engineering and Earthquake Simulation Laboratory
Test LG-0

Objectives
Actuator Controls (X, Y & Rotation)
 Sand Pumping (Target Dr ~40-50%)
 Feasibility of Inducing Liquefaction
 Safety Checks
 Instrumentation placement & operational Checks


Instrumentation
Accelerometers (33 on rings, 8 inside soil, --- on Shaking Base)
 ShapeAccel Array (4 arrays, 3x24 sensors/array)
 Piezometers (15)
 Potentiometers (18 on rings, 3 on ground surface)
 Video (4)

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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Test Summary
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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Test Preparation
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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Sensor Names & Locations
East – Reaction Wall & Actuators; PO-Potentiometer; PW – Piezometer; S – Accelerometer in soil; L –
Accelerometer on ring; B – accelerometer on shaking base; Red triangle – Shape Accel Array
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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Instrumentation
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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Instrumentation Table
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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Bucket Density Data
• Water Depth Varied slightly ~ 1 to 2.5 ft (tighter control needed in future)
• Nearly Consistent slurry
• Slurry Discharge through a Horizontal Diffuser
• Delivery Pipe - Vertical inside sand box & Moved Horizontally by crane to
spread the discharged sand
• About 4 Days to Fill about 5m sand
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Structural Engineering and Earthquake Simulation Laboratory
CPT Locations
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Structural Engineering and Earthquake Simulation Laboratory
CPT Testing
Read-out Box
Electrical standard friction cone:
Tip area= 15cm2
Friction sleeve area=200 cm2
The CPT tip resistance and side friction
data recorded at 4” depth intervals during
penetration.
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Structural Engineering and Earthquake Simulation Laboratory
Inferred Relative Density Profile
Relative Density, Dr (%)
0
20
40
60
80
100
0
2
4
Depth, (ft)
6
8
10
12
14
Jamiolkowski, 2001
Schmertmann, 1976
16
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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Sensor Data
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Structural Engineering and Earthquake Simulation Laboratory
Reference & Feedback Actuator Accelerations
0.4
a4
Acceleration (g)
0.3
a3
0.2
0.1
0.0
a1
a2
Reference
Acceleration
a1=0.01 g (5 sec)
a2=0.05 g (10 sec)
-0.1
-0.2
a3=0.15 g (10 sec)
-0.3
-0.4
0
10
Time (s)
20
30
a4=0.3 g (10 sec)
0.4
0.3
Acceleration (g)
0.2
0.1
Feedback
Acceleration
0
-0.1
-0.2
-0.3
-0.4
0
10
20
Time (s)
30
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Structural Engineering and Earthquake Simulation Laboratory
Base Shaking - Actuator Forces
Act1 Load Cell
15
Force (Kip)
10
5
0
-5
-10
-15
0
10
20
Time (s)
30
Act2 Load Cell
15
Force (Kip)
10
5
0
-5
-10
-15
0
10
20
30
Time (s)
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Structural Engineering and Earthquake Simulation Laboratory
Differential Force in Actuators
15
Force (Kip)
10
5
0
-5
-10
Act1-Act2 Force
-15
0
5
10
15
20
Time (s)
25
30
35
Actuators 1 and 2 appear to lag one another; May need fine tuning…..
But, this fine tuning may wait….
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Structural Engineering and Earthquake Simulation Laboratory
Sample Results

X&Y Accel. (on Ring and Soil) (Total soil Depth=16ft)


X&Y Accel. (on Ring)





PW13 (@ EL. 2.5 ft)
PW14(@ 7.5 ft)
PW15(@ 12 ft)
PW3(@ 14 ft)
ShapeAccelArray (SAA40019_12_21)




ay/ax at different time zones
4 PPT’s


Variation of PGA with depth at different time zones on ring
X&Y Accel. (on Base Plate)


@ EL. 4 ft, 8.5ft, 12.5ft and 16ft
Stress-Strain Curve
Stress-Time
Strain-Time
3 Potentiometers (@ top of soil; EL.16 ft)



PO1
PO2
PO3
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Structural Engineering and Earthquake Simulation Laboratory
Acceleration of soil and ring 5 @ EL. 4ft
Acceleration of the Soil and Ring @ 5ft above base plate
0.3
S5x
Lw5x
Acceleration (g)
0.2
0.1
0
-0.1
-0.2
-0.3
0
2.5
5
7.5
10
12.5 15
17.5
20
22.5 25
27.5
30
32.5 35
37.5
Time (s)
Data obtained from Pacific DAQ (time lag ~2.5s? – This will be resolved before VTC meeting on 12th)
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Structural Engineering and Earthquake Simulation Laboratory
Acceleration of soil and ring 5 @ EL. 4ft
0.08
S5x
Lw5x
Acceleration (g)
0.06
Data obtained
from Pacific
DAQ
0.04
0.02
0
-0.02
(time lag ~2.5s?)
-0.04
-0.06
-0.08
0
2.5
5
Time (s)
7.5
10
12.5
0.08
Acceleration (g)
0.06
0.04
Data obtained
from SAA
40019_12_21
(Vertex 1)
0.02
0
-0.02
-0.04
-0.06
(time lag ~ 4s?)
-0.08
0
2.5
5
Time (sec)
7.5
10
12.5
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Structural Engineering and Earthquake Simulation Laboratory
Acceleration of soil and ring 10 @ 8.5ft
0.05
S4x
Lw10x
0.04
Data obtained
from Pacific
DAQ
Acceleration (g)
0.03
0.02
0.01
0
-0.01
-0.02
-0.03
-0.04
-0.05
0
2.5
5
7.5
10
12.5
Acceleration (g)
Time (s)
0.05
0.04
0.03
0.02
0.01
0
-0.01
-0.02
-0.03
-0.04
-0.05
Data obtained
from SAA
40019_12_21
(Vertex 6)
0
2.5
5
7.5
Time (sec)
10
12.5
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Structural Engineering and Earthquake Simulation Laboratory
Acceleration of soil and ring 16 @ 12.5ft
Acceleration (g)
0.06
S3x
Lw16x
0.04
Data obtained
from Pacific
DAQ
0.02
0
-0.02
-0.04
-0.06
0
2.5
5
7.5
10
12.5
Time (s)
0.06
Acceleration (g)
0.04
Data obtained
from SAA
40019_12_21
(Vertex 10)
0.02
0
-0.02
-0.04
-0.06
0
2.5
5
Time (sec)
7.5
10
12.5
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Structural Engineering and Earthquake Simulation Laboratory
Acceleration (g)
Acceleration of soil and ring @ 16ft
0.1
0.08
0.06
0.04
0.02
0
-0.02
-0.04
-0.06
-0.08
-0.1
Data obtained
from Pacific
DAQ
S2x
Lw20x
0
2.5
5
Time (s)
7.5
10
12.5
0.1
0.08
Data obtained
from SAA
40019_12_21
(Vertex 13)
Acceleration (g)
0.06
0.04
0.02
0
-0.02
-0.04
-0.06
-0.08
-0.1
0
2.5
5
7.5
Time (sec)
10
12.5
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Structural Engineering and Earthquake Simulation Laboratory
LG-0 Accelerometer Data
• The
accelerometers in the soil and SAA starts to
differ from Ring accelerometers just a few seconds
after strong base shaking at 0.05g
• Are ring accelerometers more stable/reliable after
liquefaction?
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Structural Engineering and Earthquake Simulation Laboratory
Variation of PGA with depth at different
time zones on Ring
18
Data obtained
from
accelerometers
on ring.
16
14
Depth (ft)
12
10
8
6
4
0-7.5s
7.5-17.5s
17.5-27.5s
27.5-37.5s
2
0
0
0.1
0.2
0.3
0.4
PGA (g)
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Structural Engineering and Earthquake Simulation Laboratory
Lateral Accelerometer Response
Very small lateral acceleration
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Structural Engineering and Earthquake Simulation Laboratory
Recorded Base Ground Motion
Base Plate X&YAccelerometers
Sample Results
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Structural Engineering and Earthquake Simulation Laboratory
Recorded Base Ground Motion
X- and Y- Accelerations at Base
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Structural Engineering and Earthquake Simulation Laboratory
Recorded Base Ground Motion
Ratio of Base Y-acc to X-acc in different time
zones
ay/ax (Base Plate)
45
B1
40
B2
35
B3
% Ratio
30
25
20
15
10
5
0
0-5
5-15
15-25
25-35
Reference Tim e Zones (s)
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Structural Engineering and Earthquake Simulation Laboratory
Recorded Ring Motion
X- and Y- Accelerations at Ring 10 @ EL8.5ft
Acceleration (g)
ax and ay @ Ring 10, EL.8.5ft
0.4
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
Lw10x
Lw10y
0
5
10
15
20
25
30
35
40
Time (s)
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Structural Engineering and Earthquake Simulation Laboratory
Recorded Ring Motion
Ratio of Ring Y-acc to X-acc in different time
zones @ EL. 4, 8.5 & 13.5 ft
ay/ax (Ring)
30
Lw5x @ EL. 4ft
% Ratio
25
Lw10x @ 8.5ft
Lw16x @ 13.5ft
20
15
10
5
0
0-5
5-15
15-25
25-35
Reference Times Zones (s)
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Structural Engineering and Earthquake Simulation Laboratory
PPT Sample
Results
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Structural Engineering and Earthquake Simulation Laboratory
Pore Pressure Transducer @ depth 2.5 ft
15
D u (kPa)
Instrument Name=pw13
Sensor location from free surface=2.5ft
10
5
PW13
0
0
50
100
150
time (sec)
200
250
300
1.4
1.2
ru
1.0
0.8
Need
depth/pore
pressure
corrections
at shallow
depths
0.6
0.4
Instrument Name=pw13
Sensor location from free surface=2.5ft
0.2
0.0
0
5
10
15
20
time (sec)
25
30
35
40
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Structural Engineering and Earthquake Simulation Laboratory
Pore Pressure Transducer @ depth 7.5 ft
D u (kPa)
30
Instrument Name=pw14
Sensor location from free surface=7.5ft
20
10
0
PW14
0
50
100
150
time (sec)
200
250
300
1.2
1.0
ru
0.8
0.6
0.4
Instrument Name=pw14
Sensor location from free surface=7.5ft
0.2
0.0
0
5
10
15
20
time (sec)
25
30
35
40
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Structural Engineering and Earthquake Simulation Laboratory
Pore Pressure Transducer @ depth 12 ft
40
Instrument Name=pw15
Sensor location from free surface=12ft
D u (kPa)
30
20
10
0
PW15
0
50
100
150
time (sec)
200
250
300
1.2
1.0
ru
0.8
0.6
0.4
0.2
Instrument Name=pw15
Sensor location from free surface=12ft
0.0
0
5
10
15
20
time (sec)
25
30
35
40
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Structural Engineering and Earthquake Simulation Laboratory
Pore Pressure Transducer @ depth 14 ft
50
Instrument Name=pw3
Sensor location from free surface=14ft
D u (kPa)
40
30
20
10
PW3
0
0
50
100
150
time (sec)
200
250
300
1.2
1.0
ru
0.8
0.6
0.4
Instrument Name=pw3
Sensor location from free surface=14ft
0.2
0.0
0
5
10
15
20
time (sec)
25
30
35
40
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Structural Engineering and Earthquake Simulation Laboratory
Pore Water Pressure Ratio
0.0
0.5
ru
1.0
1.5
0
2
4
depth (ft)
6
8
Need depth/pore
pressure
corrections at
shallow depths
10
12
14
16
t=5sec
t=7sec
t=10sec
t=20sec
t=30sec
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Structural Engineering and Earthquake Simulation Laboratory
ShapeAccelArray Positions
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Structural Engineering and Earthquake Simulation Laboratory
Stress-Strain Curve (Draft)
SAA 40019_12_21
Data @ EL. 3.5 ft
40
shear strain(%)
30
20
Stress-strain data unreliable after liquefaction
10
0
3
-10
2
-20
0
5
10
15
time (sec)
20
25
30
shear stress (kPa)
5
2.5
shear stress (kPa)
-30
1
0
-1
-2
0
-3
-2.5
-4
-5
-25
0
5
10
15
time (sec)
20
25
30
-5
15
shear strain (% )
35
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Structural Engineering and Earthquake Simulation Laboratory
Stress-Strain Curve (Draft)
10
SAA 40019_12_21
Data @ EL. 8.5 ft
shear strain(%)
5
1.5
0
1
-10
0
5
10
15
time (sec)
20
25
30
shear stress (kPa)
2.5
shear stress (kPa)
-5
0.5
0
-0.5
1.25
-1
0
-1.5
-10
-1.25
-5
0
shear strain (% )
5
Stress-strain data unreliable after liquefaction
-2.5
0
5
10
15
time (sec)
20
25
30
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Structural Engineering and Earthquake Simulation Laboratory
Stress-Strain Curve (Draft)
10
SAA 40019_12_21
Data @ EL.12.5 ft
shear strain(%)
5
0
0.8
-5
0.6
-10
0
5
10
15
time (sec)
20
25
30
shear stress (kPa)
2.5
shear stress (kPa)
0.4
0.2
0
-0.2
1.25
-0.4
-0.6
0
-0.8
-5
-1.25
-2.5
-2.5
0
shear strain (% )
2.5
5
Stress-strain data unreliable after liquefaction
0
5
10
15
20
time (sec)
25
30
35
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Structural Engineering and Earthquake Simulation Laboratory
Ground Surface Settlement Results
0
50
time (sec)
100
150
200
250
0
PO1
0.5
PO2
300
PO3
Settlement (in)
1
1.5
2
2.5
3
3.5
4
4.5
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Structural Engineering and Earthquake Simulation Laboratory

3D Data Viewer (nees.rpi.edu/3dviewer)
Not yet utilized

Potentiometers – Lateral
Not yet analyzed
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Structural Engineering and Earthquake Simulation Laboratory
Draft Findings - Summary
Actuator Controls (X, Y & Rotation)
– Appears to be working with very little lateral shaking
 Sand Pumping (Target Dr ~40-50%)
– Feasible (but care necessary)
 Feasibility of Inducing Liquefaction
– Feasible (liquefies at very small shaking intensity…due to
loose…sand)
 Safety Checks
– Level ground ok, but…sloping ground needs more care….
 Instrumentation placement & operational Checks
– instruments function well; time-synchronizing…need to check
and make sure; accelerometers inside soil disorients and SAA
behaves different from sand after liquefaction

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Structural Engineering and Earthquake Simulation Laboratory
Yr-2 Test Schedule & Budget
1. Laminar Box Adaptations &
Improvements
- January 4 – March 28, 2007
(detail schedule given in next slides)
2. SG-1 & Pile Tests
- April 1 – December 5, 2007
(detail schedule given in next slides)
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Laminar Box Adaptations
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Laminar Box Adaptations
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Laminar Box Adaptations
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for SG-1 (Sloping Ground) Test
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory
Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory