A Self-Learning Manual - Institution of Engineers Mauritius

A Self-Learning Manual
Mastering Different Fields of Civil Engineering Works (VC-Q&A Method) Vincent T. H. CHU
Level One (Core FAQs)
Part III: Pile Tests
1. What is the purpose of conducting load test for piling works?
(PLT1)
Pile load test provides information on ultimate bearing capacity but not
settlement behavior. In essence, it can determine if the load is taken up by
the stratum designed or if the centre of resistance is at the design location
in piles as suggested by Robert D. Chellis (1961).
After conducting load tests, the curve of movement of pile head
(Settlement against load) and the curve of plastic deformation can be
plotted. By subtracting the curve of plastic deformation from the curve of
pile head movement at each load, the curve of elastic deformation can be
obtained. For piles of end-bearing type unrestrained by friction, the
theoretical elastic deformation can be calculated from e=RL/AE where e is
elastic deformation, L is pile length, A is area of pile, E is Young’s Modulus
of pile material and R is the reaction load on pile. By substituting e in the
formula, the elastic deformation read from the curve of elastic deformation,
L can be obtained which shows the location of the centre of resistance
corresponding to that load.
Fig. Settlement load curve in pile load test
2. What are the meanings of the mathematical terms in failure criteria
of pile load test? (PLT2)
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