neesr-vtc rpi centrifuge calibration da ha sept. 26, 2005

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 Test@12.2g

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