Bearing capacity analysis of offshore pipe piles with CPTs by considering uncertainly

Bearing capacity of offshore pipe pile is difficult to predict due to the soil variability and uncertainly associated with the field investigation and soil-pile interactions. This paper examines factors affected prediction errors of bearing capacity based on the in-situ cone penetration test (CPT) results for pipe piles. The uncertainly of transformation, geomaterials and field experiments were characterized with 33 experimental bearing capacity test results. A modified CPT based bearing capacity calculation approach was proposed by a probability evaluation method. A field full-scale bearing capacity test for offshore pipe piles was carried out. The test results were presented and discussed. Then, the American Petroleum Institute (API) and Det Norske Veritas (DNV) and the proposed modified approach were used to verify with the measurement results. Through the comparative analysis, it shown that the API approach has better performance than the DNV method for this field project case. However, both the API and DNV approaches have prediction errors greater than 5.3% which is higher than that from the modified approach. Apart from that, the modified approach could indicate results with various confidence intervals, which would helpful for the design of pipe piles.