Calibration Test Results of Rapid Load Test on Bored Piles Embedded in Sedimentary Rock Formation in Singapore

In Singapore’s local practices, the results of RLT are typically interpreted by the Unloading Point Method (UPM) to
subtract the inertia and damping effects, and deriving the equivalent static load displacement curves. However, there
are concerns on the reliability of equivalent static pile behaviour derived from RLT to represent pile behaviour under
static load, in view of the significant differences in loading duration. In view of this concern, the local Building &
Construction Authority (BCA) of Singapore has requested that each project that intend to adopt RLT as part of the
pile load test regime shall have at least one calibration test performed on the same site in similar ground conditions
to demonstrate the reliability of equivalent static pile response derived from RLT, and to establish “Correction
Factor” if any. Correction Factor is typically derived by methodology outlined in Annex A of ISO 22477-10:2016.
This paper presents the results of correlation tests of cast in-situ bored piles embedded in Sedimentary Rock
Formation (locally named as Jurong Formation) found in west southern side of Singapore Island. The comparisons of
RLT and conventional results are discussed from the aspects of load displacement response and axial load
distribution characteristics. At the end of the paper, the significant influence of percentage of end bearing
contribution on correlation factor is highlighted.