Second-Order Reliability Method
The Second-Order Reliability Method (SORM) is an extension of FORM that improves failure probability estimates by accounting for the curvature of the limit-state surface at the design point. Introduced by Fiessler, Neumann, and Rackwitz in 1979, SORM provides more accurate approximations for nonlinear failure surfaces while remaining computationally efficient. It has become the standard refinement when FORM accuracy is insufficient.
Source record
Citations copied verbatim from the method’s source record. No claim-level verification is inferred from them.
- Fiessler, B., Neumann, H. J., & Rackwitz, R. (1979). Quadratic limit states in structural reliability. Journal of the Engineering Mechanics Division, 105(4), 661-676. · DOI 10.1061/jmcea3.0002512
- Breitung, K. (1984). Asymptotic approximations for multinormal integrals. Journal of Engineering Mechanics, 110(3), 357-366. · DOI 10.1061/(ASCE)0733-9399(1984)110:3(357)
- Hohenbichler, M., & Rackwitz, R. (1988). Improvement of second-order reliability estimates by importance sampling. Journal of Engineering Mechanics, 114(12), 2195-2199. · DOI 10.1061/(ASCE)0733-9399(1988)114:12(2195)
- Melchers, R. E. (2002). Structural Reliability Analysis and Prediction (2nd ed.). John Wiley & Sons. · URL
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