Chapter 4
Reliability Analysis of Structural Components 4.1 Introduction
4.2 Second Moment Methods
4.3 First Order Reliability Method
4.4 Second Order Reliability Method
Lack-of-Invariant Problem (Ditlevsen, 1973)
Deficiencies of MVFOSM
See Example4.1
in MathCAD environment.
Historical Contribution of MVFOSM
–The MVFOSM was used to derive earlier versions of the reliability-based design formats, such as the American Institute of Steel Construction, Inc. (AISC 1986), Canadian Standard Associations (CSA, 1974), ComitéEuropean du Béton (CEB, 1986), etc.
–Does not use the distribution information of the basic RVs, when they are available.–When LSF is nonlinear, significant error may be introduced by neglecting higher order terms.
–The reliability index fails to be constant under different but mechanically equivalent formulations of the same performance function.
–Probability transformation to standard space –Definition of a new reliability index
–Expansion of a nonlinear LSF at the design point, instead of the mean value point.
–
Finding the design point by an iterative search method.
Hasofer-Lind Method (AFOSM)