1. Schueremans1, P. Smars2, D. Van Gemert1


Nowadays, powerful methods are available for the calculation of structural safety values. These permit to calculate the global failure probability of complex structures, relying on deterministic techniques able to determine the stability state for a prescribed set of parameters. The safety of arches is a typical example of new fields for these methods. Traditionally their stability is assessed using a deterministic approach, resulting in safety factors. To relate these safety factors to an absolute safety, requires a great deal of engineering judgement. In case of an existing arch, this judgement depends on a variety of uncertainties such as on the accuracy of the geometry measurements, the uncertainty on the material properties, support conditions and the constructional history of the structure. The proposed method calculates an absolute value for the global probability of failure at level III on the basis of the quantified uncertainties. Several techniques are available for the calculation of the global probability of failure at level III such as Monte Carlo, first order reliability method or second order reliability method (FORM/SORM) in combination with a system analysis. The recently developed directional adaptive response surface sampling method (DARS) meets both requirements of accuracy and efficiency. This method will be used to calculate the global probability of failure of arches in combination with the limit analysis code Calipous.

Key words: reliability analysis, failure probability, arch, structural safety, DARS, assessment