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Structural Engineering and Earthquake Simulation Laboratory 1 Task 1 (1g Tests) Experimental and Micromechanical Computational Study of Pile Foundations.

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Presentation on theme: "Structural Engineering and Earthquake Simulation Laboratory 1 Task 1 (1g Tests) Experimental and Micromechanical Computational Study of Pile Foundations."— Presentation transcript:

1 Structural Engineering and Earthquake Simulation Laboratory 1 Task 1 (1g Tests) 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)

2 Structural Engineering and Earthquake Simulation Laboratory 2 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

3 Structural Engineering and Earthquake Simulation Laboratory 3 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) Test LG-0

4 Structural Engineering and Earthquake Simulation Laboratory 4 LG-0 Test Summary

5 Structural Engineering and Earthquake Simulation Laboratory 5 LG-0 Test Preparation

6 Structural Engineering and Earthquake Simulation Laboratory 6 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

7 Structural Engineering and Earthquake Simulation Laboratory 7 LG-0 Instrumentation

8 Structural Engineering and Earthquake Simulation Laboratory 8 LG-0 Instrumentation Table

9 Structural Engineering and Earthquake Simulation Laboratory 9 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

10 Structural Engineering and Earthquake Simulation Laboratory 10 CPT Locations

11 Structural Engineering and Earthquake Simulation Laboratory 11 CPT Testing Read-out Box The CPT tip resistance and side friction data recorded at 4” depth intervals during penetration. Electrical standard friction cone: Tip area= 15cm 2 Tip area= 15cm 2 Friction sleeve area=200 cm 2

12 Structural Engineering and Earthquake Simulation Laboratory 12 Inferred Relative Density Profile

13 Structural Engineering and Earthquake Simulation Laboratory 13 LG-0 Sensor Data

14 Structural Engineering and Earthquake Simulation Laboratory 14 Reference & Feedback Actuator Accelerations a 1 =0.01 g (5 sec) a 2 =0.05 g (10 sec) a 3 =0.15 g (10 sec) a 4 =0.3 g (10 sec) a1a1 a2a2 a3a3 a4a4 Feedback Acceleration Reference Acceleration

15 Structural Engineering and Earthquake Simulation Laboratory 15 Base Shaking - Actuator Forces

16 Structural Engineering and Earthquake Simulation Laboratory 16 Differential Force in Actuators Actuators 1 and 2 appear to lag one another; May need fine tuning….. But, this fine tuning may wait….

17 Structural Engineering and Earthquake Simulation Laboratory 17 Sample Results X&Y Accel. (on Ring and Soil) (Total soil Depth=16ft)  @ EL. 4 ft, 8.5ft, 12.5ft and 16ft X&Y Accel. (on Ring)  Variation of PGA with depth at different time zones on ring X&Y Accel. (on Base Plate)  a y /a x at different time zones 4 PPT’s  PW13 (@ EL. 2.5 ft)  PW14(@ 7.5 ft)  PW15(@ 12 ft)  PW3(@ 14 ft) ShapeAccelArray (SAA40019_12_21)  Stress-Strain Curve  Stress-Time  Strain-Time 3 Potentiometers (@ top of soil; EL.16 ft)  PO1  PO2  PO3

18 Structural Engineering and Earthquake Simulation Laboratory 18 Data obtained from Pacific DAQ (time lag ~2.5s? – This will be resolved before VTC meeting on 12th) Acceleration of soil and ring 5 @ EL. 4ft

19 Structural Engineering and Earthquake Simulation Laboratory 19 Data obtained from Pacific DAQ (time lag ~2.5s?) Data obtained from SAA 40019_12_21 (Vertex 1) (time lag ~ 4s?) Acceleration of soil and ring 5 @ EL. 4ft

20 Structural Engineering and Earthquake Simulation Laboratory 20 Data obtained from Pacific DAQ Data obtained from SAA 40019_12_21 (Vertex 6) Acceleration of soil and ring 10 @ 8.5ft

21 Structural Engineering and Earthquake Simulation Laboratory 21 Data obtained from Pacific DAQ Data obtained from SAA 40019_12_21 (Vertex 10) Acceleration of soil and ring 16 @ 12.5ft

22 Structural Engineering and Earthquake Simulation Laboratory 22 Data obtained from Pacific DAQ Data obtained from SAA 40019_12_21 (Vertex 13) Acceleration of soil and ring @ 16ft

23 Structural Engineering and Earthquake Simulation Laboratory 23 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?

24 Structural Engineering and Earthquake Simulation Laboratory 24 Variation of PGA with depth at different time zones on Ring Data obtained from accelerometers on ring.

25 Structural Engineering and Earthquake Simulation Laboratory 25 Lateral Accelerometer Response Very small lateral acceleration

26 Structural Engineering and Earthquake Simulation Laboratory 26 Base Plate X&Y- Accelerometers Sample Results Recorded Base Ground Motion

27 Structural Engineering and Earthquake Simulation Laboratory 27 Recorded Base Ground Motion X- and Y- Accelerations at Base

28 Structural Engineering and Earthquake Simulation Laboratory 28 Recorded Base Ground Motion Ratio of Base Y-acc to X-acc in different time zones

29 Structural Engineering and Earthquake Simulation Laboratory 29 Recorded Ring Motion X- and Y- Accelerations at Ring 10 @ EL8.5ft

30 Structural Engineering and Earthquake Simulation Laboratory 30 Recorded Ring Motion Ratio of Ring Y-acc to X-acc in different time zones @ EL. 4, 8.5 & 13.5 ft

31 Structural Engineering and Earthquake Simulation Laboratory 31 PPT Sample Results

32 Structural Engineering and Earthquake Simulation Laboratory 32 PW13 Pore Pressure Transducer @ depth 2.5 ft Need depth/pore pressure corrections at shallow depths

33 Structural Engineering and Earthquake Simulation Laboratory 33 PW14 Pore Pressure Transducer @ depth 7.5 ft

34 Structural Engineering and Earthquake Simulation Laboratory 34 PW15 Pore Pressure Transducer @ depth 12 ft

35 Structural Engineering and Earthquake Simulation Laboratory 35 PW3 Pore Pressure Transducer @ depth 14 ft

36 Structural Engineering and Earthquake Simulation Laboratory 36 Pore Water Pressure Ratio Need depth/pore pressure corrections at shallow depths

37 Structural Engineering and Earthquake Simulation Laboratory 37 ShapeAccelArray Positions

38 Structural Engineering and Earthquake Simulation Laboratory 38 Stress-Strain Curve (Draft) SAA 40019_12_21 Data @ EL. 3.5 ft Stress-strain data unreliable after liquefaction

39 Structural Engineering and Earthquake Simulation Laboratory 39 Stress-Strain Curve (Draft) SAA 40019_12_21 Data @ EL. 8.5 ft Stress-strain data unreliable after liquefaction

40 Structural Engineering and Earthquake Simulation Laboratory 40 Stress-Strain Curve (Draft) SAA 40019_12_21 Data @ EL. 12.5 ft Stress-strain data unreliable after liquefaction

41 Structural Engineering and Earthquake Simulation Laboratory 41 Ground Surface Settlement Results

42 Structural Engineering and Earthquake Simulation Laboratory 42 3D Data Viewer (nees.rpi.edu/3dviewer) 3D Data Viewer (nees.rpi.edu/3dviewer) Not yet utilized Potentiometers – Lateral Potentiometers – Lateral Not yet analyzed

43 Structural Engineering and Earthquake Simulation Laboratory 43 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 Draft Findings - Summary

44 Structural Engineering and Earthquake Simulation Laboratory 44 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)

45 Structural Engineering and Earthquake Simulation Laboratory 45 Schedule for Laminar Box Adaptations

46 Structural Engineering and Earthquake Simulation Laboratory 46 Schedule for Laminar Box Adaptations

47 Structural Engineering and Earthquake Simulation Laboratory 47 Schedule for Laminar Box Adaptations

48 Structural Engineering and Earthquake Simulation Laboratory 48 Schedule for SG-1 (Sloping Ground) Test

49 Structural Engineering and Earthquake Simulation Laboratory 49 Schedule for Pile Tests

50 Structural Engineering and Earthquake Simulation Laboratory 50 Schedule for Pile Tests

51 Structural Engineering and Earthquake Simulation Laboratory 51 Schedule for Pile Tests

52 Structural Engineering and Earthquake Simulation Laboratory 52 Schedule for Pile Tests

53 Structural Engineering and Earthquake Simulation Laboratory 53 Schedule for Pile Tests

54 Structural Engineering and Earthquake Simulation Laboratory 54 Schedule for Pile Tests


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