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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)
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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
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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
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Structural Engineering and Earthquake Simulation Laboratory 4 LG-0 Test Summary
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Structural Engineering and Earthquake Simulation Laboratory 5 LG-0 Test Preparation
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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
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Structural Engineering and Earthquake Simulation Laboratory 7 LG-0 Instrumentation
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Structural Engineering and Earthquake Simulation Laboratory 8 LG-0 Instrumentation Table
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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
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Structural Engineering and Earthquake Simulation Laboratory 10 CPT Locations
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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
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Structural Engineering and Earthquake Simulation Laboratory 12 Inferred Relative Density Profile
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Structural Engineering and Earthquake Simulation Laboratory 13 LG-0 Sensor Data
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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
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Structural Engineering and Earthquake Simulation Laboratory 15 Base Shaking - Actuator Forces
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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….
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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
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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
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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
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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
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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
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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
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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?
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Structural Engineering and Earthquake Simulation Laboratory 24 Variation of PGA with depth at different time zones on Ring Data obtained from accelerometers on ring.
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Structural Engineering and Earthquake Simulation Laboratory 25 Lateral Accelerometer Response Very small lateral acceleration
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Structural Engineering and Earthquake Simulation Laboratory 26 Base Plate X&Y- Accelerometers Sample Results Recorded Base Ground Motion
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Structural Engineering and Earthquake Simulation Laboratory 27 Recorded Base Ground Motion X- and Y- Accelerations at Base
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Structural Engineering and Earthquake Simulation Laboratory 28 Recorded Base Ground Motion Ratio of Base Y-acc to X-acc in different time zones
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Structural Engineering and Earthquake Simulation Laboratory 29 Recorded Ring Motion X- and Y- Accelerations at Ring 10 @ EL8.5ft
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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
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Structural Engineering and Earthquake Simulation Laboratory 31 PPT Sample Results
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Structural Engineering and Earthquake Simulation Laboratory 32 PW13 Pore Pressure Transducer @ depth 2.5 ft Need depth/pore pressure corrections at shallow depths
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Structural Engineering and Earthquake Simulation Laboratory 33 PW14 Pore Pressure Transducer @ depth 7.5 ft
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Structural Engineering and Earthquake Simulation Laboratory 34 PW15 Pore Pressure Transducer @ depth 12 ft
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Structural Engineering and Earthquake Simulation Laboratory 35 PW3 Pore Pressure Transducer @ depth 14 ft
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Structural Engineering and Earthquake Simulation Laboratory 36 Pore Water Pressure Ratio Need depth/pore pressure corrections at shallow depths
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Structural Engineering and Earthquake Simulation Laboratory 37 ShapeAccelArray Positions
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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
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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
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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
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Structural Engineering and Earthquake Simulation Laboratory 41 Ground Surface Settlement Results
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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
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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
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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)
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Structural Engineering and Earthquake Simulation Laboratory 45 Schedule for Laminar Box Adaptations
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Structural Engineering and Earthquake Simulation Laboratory 46 Schedule for Laminar Box Adaptations
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Structural Engineering and Earthquake Simulation Laboratory 47 Schedule for Laminar Box Adaptations
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Structural Engineering and Earthquake Simulation Laboratory 48 Schedule for SG-1 (Sloping Ground) Test
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Structural Engineering and Earthquake Simulation Laboratory 49 Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory 50 Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory 51 Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory 52 Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory 53 Schedule for Pile Tests
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Structural Engineering and Earthquake Simulation Laboratory 54 Schedule for Pile Tests
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