Strutures, Safety and Reliability

Recommended Design Fatigue Factors for Reassessment of Piles Subjected to Dynamic Actions From Driving

[+] Author and Article Information
Inge Lotsberg

 DNV, Veritasveien 1, Oslo, 1322 Norway

Gudfinnur Sigurdsson

 DNV, Veritasveien 1, Oslo, 1322 Norwaygudfinur.sigurdsson@dnv.com

Knut Arnesen

 DNV, Veritasveien 1, Oslo, 1322 Norwayknut.arnesen@dnv.com

Michael E. Hall

 ConocoPhillips Norge AS, Ekofiskveien 35, Tananger Stavanger, 4056 Norwaymichael.hall@conocophillips.com

J. Offshore Mech. Arct. Eng 132(4), 041603 (Sep 23, 2010) (8 pages) doi:10.1115/1.4001418 History: Received September 20, 2008; Revised December 16, 2009; Published September 23, 2010; Online September 23, 2010

Calculated probabilities of fatigue failure depend on the analysis procedure used for design. Calculated probabilities of a fatigue failure also depend on long term stress ranges due to loading and uncertainties associated with this. In order to ensure the consistent safety level for assessment of fatigue failure, the design fatigue factors (DFFs) to be used for fatigue design should be dependent on the analysis procedure and premises used. In the present paper, an assessment of appropriate DFFs for piles subjected to dynamic actions from pile driving has been performed by probabilistic analysis based on: uncertainty with respect to dynamic cyclic stress during pile driving, and fatigue capacity of circumferential welds in piles. Accumulated probabilities of fatigue failures in pile butt welds are presented. An assessment of uncertainties involved in calculation of stress ranges during pile driving has been performed. It is shown that the uncertainty in loading when driving records are known is lower than that estimated on the basis of soil data. Thus, in order to obtain consistent safety levels, different DFFs should be used when calculated stress ranges are derived based on soil data only, as compared with the actual stress ranges and number of blows determined from driving records. The results from probabilistic analyses together with recommended design fatigue factors are presented in this paper.

Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 3

Calculated stress ranges for pile at Ekofisk 2/4 B platform

Grahic Jump Location
Figure 1

Overview of the driven pile

Grahic Jump Location
Figure 2

Butt weld in pile

Grahic Jump Location
Figure 4

Resistance as function of blows counts

Grahic Jump Location
Figure 6

Maximum allowable misalignment in butt welds according to Norsok M-101

Grahic Jump Location
Figure 8

Relation between standard deviations in S-N data and S-N data including misalignment

Grahic Jump Location
Figure 9

Probability of failure as function of CoV on nominal stress range in pile with thickness 25 mm

Grahic Jump Location
Figure 10

Probability of failure as function of CoV on nominal stress range in pile with thickness 50 mm

Grahic Jump Location
Figure 11

Probability of failure as function of CoV on nominal stress range in pile with thickness 100 mm

Grahic Jump Location
Figure 5

Relative increase in number of cycles as function of relative increase in resistance

Grahic Jump Location
Figure 7

Relation between mean loga values in S-N data and S-N data including misalignment



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In