neesr-vtc rpi centrifuge calibration da ha sept. 26, 2005
TRANSCRIPT
NEESR-VTCRPI Centrifuge Calibration
Da Ha
Sept. 26, 2005
Dummy Pipe Setup (Not to scale)
1A 2A 3A
1B 2B 3B
Strain Gages
1B 2B 3B
1A 2A 3A
Ideal Shape:
Real Shape( Exaggerated):
Step Loading Tension Test
Loading: 1kg, 2kg, 4kg and 6kg
0 500 1000 1500 2000 2500 3000 3500 40000
100
200
300
400
500
600
700Filtered Strain Gage Readings
Time (sec)
Str
ain
Gag
e R
eadi
ngs
(mic
ro s
trai
n)
A1A2A3B1B2B3
Tension Test:
• Pre-existing curvature effects recorded strain
• Gages with pre-existing tension creep
• Will use load- strain data to calculate E
Cantilever Test #1
Loading Sequence: 224g, 424 g, 224g and 0g
3B 2B 1B
3A 2A 1A
Load
32.75”4” 28.75”
Cantilever Test #1:
• Inelastic behavior at moderate strain of 0.4%- non-zero strain after loads removed
• Axial strain, although small, not consistent with geometry of load. Modulus in tension different than modulus in compression?
Cantilever Test #2
Loading: 124g, 224g and 324g
1A 2A 3A
1B 2B 3B
Load
32.75”4” 28.75”
Tension Test w/ Splitbox
No Soil 1G Test
Peak Displacement= 1.1cm
Expected Strain
No Soil Splitbox Test:
• Difference between measured and expected strain may be due to compliance of end connecters at box wall.
• Small bending strain likely due to pre-existing curvature
Centrifuge Dummy [email protected]
6 Strain Gages, 1 malfunctioned at beginning and another malfunctioned @
3.2% strain
Dummy Pipe Setup (Not to scale)
1A 2A 3A
1B 2B 3B
Strain Gages
Malfunctioned
Malfunctioned
Centrifuge Dummy Test:
• End connection acting like pin
• Due to strain gage malfunction cannot calculate axial and bending strains
After Test Check:
• Soil Unit Weight = 13.0 kN/m3=> = 33o
Expected Unit Weight = 14.4 kN/m3=> = 37o
• Water Content = 3.0%
Expected Water Content= 4.0%
Photos from Dummy Test