7. Advantages
Low noise and vibrations
Small, maneuverable
installation equipment
Removal and replacement
Ease of transport
Compression or tension
All-weather installation
Rapid installation
Does not produce drill spoil
Immediate post tensioning
Shorter bond length
Do not require casing
8. Disadvantages
Cannot penetrate very hard
rock (SPT N>100)
Concrete and construction
debris is problematic
Difficult in cobble and
boulders
Ease of installation means
contractor pre-qualification
important
Slender shaft makes lateral
bracing imperative
13. Torque Verification
Hoyt and Clemence
(1989)
-91 Full-scale tension
load tests
-Torque is statistically a
strong verification of
capacity
-Capacity:torque ratio
depends mostly on hub
diameter
April 2008