KLAVS FEILBERG HANSEN* ESA NYKANEN** and FINN R. GOTTFREDSEN* * Danish Building Research Institute ** VTT Building Technology, Espoo, Finland

The results of 26 deformation controlled shear tests with one bed joint between two bricks at different levels of precompression are presented in this paper. The test setup is similar to one used by VAN DER PLUIJM and makes it possible to determine the shear strength and shear stiffness as well as the post peak behaviour of bed joints, including mode II fracture energy which is the fracture energy related to shear failure and joint dilatancy. The tests were carried out with three mortars, two solid and two perforated bricks. The mode II fracture energy in bed joints is significantly larger for perforated bricks than for solid bricks and attains its maximum value when relatively weak mortars are used. Previous tests on walls had shown that this can result in a 50% increase in the deformation capacity of masonry in out-of-plane bending.