Influence of the behaviour of calcium silicate brick and element masonry on the lateral capacity of structures

In recent years induced seismicity in the Netherlands considerably increased. This phenomenon has a wide impact on the built environment, which is mainly composed by unreinforced masonry (URM) structures. These buildings were not designed for seismic loading, and present peculiar characteristics include very slender walls (100 mm thickness and 2.5m in height), limited connections between walls and floors, and use of cavity walls.
A large portion of the URM building stock consists of terraced houses in which the presence of calcium silicate (CS) masonry is often used. The CS masonry is used to build the loadbearing walls, which are part of the cavity wall system. The cavity walls are generally composed of two leaves of masonry separated by an empty cavity, having a thickness of 8-6 mm, and connected with steel anchors. On the basis of the construction year, different masonry unit were adopted to build the inner loadbearing leave: in the period 1960-1980 small CS brick and general purpose mortar were used, while after 1980, the presence of large CS elements and thin mortal layers is predominant. Although these materials are often used in the northern part of Europe, little information is available on their material and structural performance.
In this paper, a comparison between the behaviour of CS brick and element masonry is presented. The results of two experimental campaigns carried out at Delft University of Technology are reported. Both masonry types have been characterised at the material level by performing standardised destructive tests, such as compression, shear, and bending tests on wallets. The characterisation at the structural level is carried out by performing quasi-static cyclic tests on full-scale two-story high assembled structures.