Page 455 - Marine Structural Design

Chapter 23 Basics of Structural Reliability 43 1

Pf,, = @(-p,)=1.7849x104

Pr,* = @(- p,)= 3.2481 x lo4
p/,3 = @(- p,) = 1.1176~ 10”

P,.4 = @(- p.,) = 2.1266 x 1 0-8
For a parallel system, the following bounds exist

Hence, the simple bounds of this parallel system can be estimated as
I
1.3779~10-*~ Pf,sp I2.1266~10”
and corresponding bounds of the reliability index can be obtained as
5.48 S psYx 19.23
It should be noted that in general, the bound values given by the equation above for parallel
system is too wide.

23.12 References

1. Ang, S.H. and Comell, C.A. (1974), “Reliability Bases of Structural Safety and Design”,
Journal of Structural Engineering, ASCE, Vol. 100, No. 9, pp. 1755-1769.
2. Ang, A.H.-S and Tang, W. (1975, 1984), “Probability Concepts in Engineering Planning
and Design, Volume I & II”, John Wiley and Sons, New York.
3. Bai, Y., Xu, T. and Bea, R. (1997), “Reliability-Based Design and Requalification Criteria
for Longitudinally Corroded Pipes”, ISOPE-1 997.
4. Comell, C.A. (1969), “A Probability-Based Structural Code”, ACI-Journal, Vol. 66, pp.
974-985.
5. Ferry-Borges, J and Castmheta, M. (1971), “Structural Safety”, Laboratoria Nacional de
Engenhera Civil, Lisbon
6. Hasofer, A.M. and Lind, N.C. (1974), “An Exact and Invariant First Order reliability
Format”, ASCE J. Eng. Mech. Div., pp.111-121.
7. Madsen, H.O., et a1 (1 986), “Methods of Structural Safety, Prentice-Hall, Inc., Englewood
Cliffs
8. Mansour, A. E., et al (1997), “Assessment of Reliability of Ship Structures”, SSC-398.
Ship Structures Committee.
9. Melchers, R.E. (1 999), “Structural Reliability Analysis and Prediction”, 2nd Edition, John
Wiley & Sons Ltd.
10. Moan, T. and Song, R. (1998), “Implication of Inspection Updating on System Fatigue
Reliability of Offshore Structures”, the Proc. 17th OMAE, Lisbon, Portugal, 1998