Residual stress measurement of driven precast piles using distributed fibre optic sensors

Stresses generated from pile installation are a critical component in understanding pile behaviour. These are known as residual stresses and in Delft, the Netherlands, the response of three driven precast piles founded in sand was measured using distributed fibre optic sensing as part of a series of full-scale static load tests. The instrumentation set-up and analysis is discussed in this paper, highlighting the uncertainties with developing an appropriate residual stress distribution and in particular, how instrumentation selection, positioning and calibration can influence the interpretation of the residual stress profiles. The resulting profiles shows a substantial development of residual stress in the pile, an important consideration to take into account when preparing and analysing full-scale load tests on driven precast piles.