CPT-Based design method for axial capacity of offshore piles in clays

2010 ◽  
pp. 573-578 ◽  
Keyword(s):  
Design Method ◽  
Axial Capacity ◽  
Offshore Piles

scholarly journals Design method reliability assessment from an extended database of axial load tests on piles driven in sand

2017 ◽  
Vol 54 (1) ◽  
pp. 59-74 ◽  
Author(s):  
Z.X. Yang ◽  
W.B. Guo ◽  
R.J. Jardine ◽  
F. Chow
Keyword(s):  
Design Method ◽  
Site Investigation ◽  
Imperial College ◽  
Axial Capacity ◽  
Reliability Parameters ◽  
Investigation Methods ◽  
Loading Uncertainty ◽  
Load Tests ◽  
Alternative Approaches ◽  
The University

The accurate prediction of axial capacity remains a challenging task for piles driven in sands. Rigorous database studies have become key tools for assessing the efficacy of design methods. This paper employs the 117 high-quality entries in the recently developed Zhejiang University – Imperial College London (ZJU–ICL) database to check for potential biases between nine prediction procedures, considering a range of factors. The analysis highlights the critical importance of addressing age after driving, open and closed ends, tension versus compression, and concrete compared to steel. It also shows the hierarchy of reliability parameters associated with the alternative approaches. The “full” Imperial College pile (ICP) approach and The University of Western Australia (UWA) approaches are found to have significant advantages in eliminating potential biases. It is also argued that design load and resistance or safety factors should be varied to match the design and site investigation methods applied, as well as the loading uncertainty and degree of load cycling, which often vary between applications. Noting that predictions for base capacities Qb are inherently less reliable than for shaft Qs, especially in rapidly varying ground profiles, credible lower bound parameters (cone resistance, qc) are recommended for Qb assessment. It is also recommended that the potential effects of cycling be addressed carefully in cases that involve substantial environmental loading.

An Integrated Approach to Offshore Pile Axial Design in Sands and Clays

2006 ◽  
Author(s):  
Neil Morgan ◽  
Ian Finnie
Keyword(s):  
Design Method ◽  
Predictive Ability ◽  
Site Investigation ◽  
Integrated Approach ◽  
Rational Approach ◽  
Axial Capacity ◽  
Site Investigations ◽  
Pile Design ◽  
Capacity Calculation ◽  
Single Method

Most offshore pile axial design is currently carried out according to API RP 2A WSD, the recommendations of which we understand are due to change. As a result there are many new pile axial capacity calculation methods emerging which may become acceptable for use, each with its own particular site investigation requirements. For the same soil input these methods usually result in just as many different capacities and it is apparent that no single design method is applicable to all design situations and it would be unusual for a single method to be completely reliable for a single platform. We examine the sources of geotechnical uncertainty and concentrate on the transformation uncertainty which is principally due to the choice of pile design method. It would be a rational approach to use a single set of soil and pile input parameters and calculate the pile capacities according to all of the methods. This paper considers two major pile test sites that have had detailed site investigations (Pentre and Euripides) and uses the API, UWA, ICP, NGI, Fugro and Kolk pile design methods to compare the results. We examine the reliability of this combined approach with depth, which shows that our predictive ability varies between shallower (e.g. less than 20 metres) and deeper penetrations. It concludes with practical recommendations on how a rational pile design may be achieved. One such approach is to take the mean average of all the capacities calculated. Optimising pile design in this manner may help to identify and reduce unwarranted conservatism and conversely help to ensure that optimum pile capacity is achieved and to avoid installation difficulties associated with piles that are unnecessarily too long.

Application of a work-centered design method to support counterspace operations

2005 ◽  
Author(s):  
Michael Szczepkowski ◽  
Kelly Neville ◽  
Ed Popp
Keyword(s):  
Design Method
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