ABSTRACT

The simple shear apparatus is shown schematically in Figure 2. Its main components are:

– a horizontal support carrying a linear motion system;

– a sliding base incorporating load cells sliding horizontally over the horizontal support;

– 10 biaxial load cells 60 mm long and 30 mm wide arranged in a matrix 5 × 2 used to simultaneously measure the shear and normal forces at the base of the specimen;

– stacked steel plates to prevent horizontal deformation during both compression and shearing;

– a loading cap constrained to move vertically by two vertical sliders;

– a piston moved by a pneumatic-cylinder to apply the vertical load during the compression stage;

– two lock nuts to lock the loading cap in order to prevent vertical deformation during shearing;

– a frame to carry the piston and the lock nuts; – two lateral supports mounting the two vertical slider

guideways and blocking the horizontal movement of the cap during shearing;

– a stepper motor to horizontally move the sliding base.