ABSTRACT
The safety concept and the partial factors for the design of masonry walls in EN 1996 and in particular the National Annexes mostly base on tradition. This is seen as an opportunity to rethink the concept and validate the historical values with studies, taking reliability theoretical approaches into account. The spatial variability of material properties can have a significant influence on the reliability of load-bearing capacity of masonry walls. This influence is highly dependent on the geometry and the material behaviour of the wall. The conducted investigations are based on a finite element model, which is set up following the simplified micro modelling approach. The spatial variability is implemented as a unit-to-unit variability for the compressive strength and the Young´s modulus. Those two material properties determine the stress-strain behaviour of the different masonry types. Furthermore, other material properties like the fracture energy must be taken into account in order to generate numerically solid results. Within each run of the conducted Monte Carlo simulation random values for the material properties are generated. The wall is then loaded until failure and a load capacity factor can be calculated. Within the study, the influence of the spatial variability on the load-bearing capacity is investigated by modifying several parameters like the wall slenderness or length. Based on an appropriate distribution function, it is possible to calculate partial safety factors in order to interpret the influence on reliability of structural resistance.
