Use of instrumented static load tests on deep foundations for optimisation of geotechnical design

Authors: Wood, WR; Sinnreich, J; Simmonds, AJ Download Paper

DOI https://doi.org/10.36487/ACG_rep/1508_49_Wood

Cite As:
Wood, WR, Sinnreich, J & Simmonds, AJ 2015, 'Use of instrumented static load tests on deep foundations for optimisation of geotechnical design', in PM Dight (ed.), FMGM 2015: Proceedings of the Ninth Symposium on Field Measurements in Geomechanics, Australian Centre for Geomechanics, Perth, pp. 677-689, https://doi.org/10.36487/ACG_rep/1508_49_Wood



Abstract:
The paper will describe through case history evidence of high and ultra-high capacity drilled shaft foundations how an integrated approach to site characterisation and site specific geotechnical design method calibration through full scale instrumented load tests will deliver significantly increased reliability and reduced cost of deep foundations for large capital infrastructure projects. Recent advances in ultrahigh capacity load testing, in excess of 300 MN on a single shaft, when combined with comprehensive in situ strain and deflection monitoring, are allowing a new generation of large diameter foundations to be designed with confidence resulting in project benefits in terms of reduced construction times and cost. A case history from the US will be described to illustrate the key theme of the paper. The paper will also describe recent advances in the interpretation of strain gauge data obtained from underground concrete structures reviewing recently developed techniques for increasing confidence in the knowledge of section properties for the determination of load from such data. Improvements in the measurements of deflections particularly with respect to the provision of a stable reference datum will be examined. The paper will have direct application to all geotechnical engineers designing deep foundations helping to set the effective use of geomonitoring in the context of their primary responsibilities to manage ground risk into the twin desired project outcomes of increased certainty of outcome and value for money.

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