Probabilistic model for compressive strength of historic masonry

Assessment of the masonry strength of the fortress in Terezin

“…(3) to (5)) yields μ f = 1.76 MPa; V f = 0.47; f d = 0.52 MPa. The design value is here assessed as the fractile of masonry strength corresponding to probability of 6.6‰ derived for β t = 3.1 [4]. In this case the probabilistic design value is equal to the value obtained deterministically.…”

“…Note that the effect of change in the target reliability index β t on μ Xi is minor. For instance all μ Xi -values reduce by about 0.01-0.02 when β t = 3.1 is accepted for historic structure instead of β t = 3.8 as proposed in [4]. 3 Case study…”

“…Unlike for f b and f m , it is usually impossible to obtain experimental data for the coefficient K in the assessment of a specific structure. Its probabilistic model was thus derived on the basis of previous experience and assessment of experimental data [4]. Table 1 gives indicative coefficients of variation of K and θ for selected test methods widely used for the investigation of historic masonry.…”

“…Lognormal distribution is also appropriate for the uncertainties θ [5]. The mean values f b and f m are described by the lognormal distribution with mean μ and standard deviation σ [4]:…”

“…In the case of historic structures, however, it may lead to expensive repairs and loss of heritage values. Probabilistic analysis is then desirable for the assessment of historical masonry [1][2][3][4] as it facilitates a rational consideration of: -Randomness of material characteristics of masonry units and mortar; -Statistical uncertainties due to a limited number of tests; -Inaccuracies of testing (often non-or minor-destructive) methods; -Simplifications adopted in the model for masonry strength (model uncertainty).…”