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.