REVIEW OF CPT DIRECT DESIGN METHODS FOR DRIVEN CAST-IN-SITU PILE CAPACITY USING INSTRUMENTED PILE LOAD TESTS TO FAILURE-PPT Presentation

PPT Presentation

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The presentation assesses CPT-based design methods for driven cast-in-situ (DCIS) pile capacity using instrumented pile load tests to failure. The case study involved 380 mm diameter piles, 8–15 m long, designed for 610–725 kN axial compression and founded in sand beneath soft alluvial soils.<br /><br />CPT capacity methods have largely been developed for precast or preformed driven piles, while DCIS piles have received limited attention. Because DCIS piles combine characteristics of different pile types, designers should check each method’s assumptions and applicability—particularly the soil conditions below the pile toe.<br /><br />Instrumented tests enabled shaft resistance to be assessed with depth and base resistance in relation to pile displacement. The Fugro-05 method showed good correlation with shaft and base capacity for all four instrumented tests. UWA-05 also correlated well with base resistance in a distinct two-layer soil profile.<br /><br />The tests highlighted the importance of residual loads, which can arise from pile driving, soil consolidation, groundwater changes, or other effects. Ignoring them may overestimate shaft friction and underestimate base resistance.<br /><br />The study concludes that a limited number of sacrificial pile tests can help calibrate working-pile load tests. Instrumentation provides valuable information for evaluating shaft and base capacity, but results must be interpreted with residual-load effects and the design basis in mind.

Keywords

CPT-based design

driven cast-in-situ piles

pile capacity

instrumented pile load tests

shaft resistance

base resistance

Fugro-05 method

UWA-05 method

residual loads

soil profile