Civil Engineering Reference
In-Depth Information
Reference beam
Tell-tale
rod for displacement
measurements
Level of cell judged to
give similar pile resistance
above and below cell
Osterberg
cell(s)
Figure 9.24
Schematic diagram of Osterberg cell method for pile load testing.
60
Load (MN)
B
B
50
A
A
Combined
(rigid pile)
40
B
30
Combined
(with pile
compression)
Upper section
A
B
A
10
Base section
0
0
−
60
−
40
−
20
0
20
40
Displacement (mm)
Figure 9.25
Example load-displacement responses from single-cell Osterberg test.
9.2.6 Other forms of pile test
9.2.6.1 Osterberg cell
A novel method for testing large diameter bored piles was introduced in the 1980s by
Dr Osterberg (Osterberg, 1989). The method comprises hydraulically operated flat-
jacks, referred to as 'Osterberg cells', which are built into the pile during construction,
and are used to load the top and bottom section of the pile against each other (see
Figure 9.24). In this way, the pile resistance may be proven to (approximately) twice
the highest load applied by the jacks, which in turn is limited by the lower of the
