A.T. VERMELTFOORT Technische Uninversiteit Eindhoven
In masonry walls, due to ‘rounding of the bed joint’, often only the central area of the unit is bonded and openings develop at the edges. Previous studies have shown that this causes a non-uniform strain distribution in concentrically loaded specimens. In this project, the effect of eccentricity was studied. Masonry specimens 25mm wide were cut from couplets. Wire cut and soft mud bricks were used. The specimens made from soft mud bricks were cracked during preparation. Nevertheless, they were used to study the closing effect of cracks. Specimens were cyclically loaded with eccentricities of –32, –16, 0, 16 and 32mm to stresses of approximately 1/3 of estimated failure load. In this project a moving seating arrangement was used to allow for free horizontal movement of the loaded bottom surface of the specimen. After some initial settlement, the load eccentricity remained constant. Deformations observed through laser interferometry confirmed the uneven strain distribution. The bending stiffness was affected by the variation in mortar properties. Moment/curvature diagrams showed a shift when changing from positive to negative rotation.