JAN KUBICA1; IWONA GALMAN2

1) Full Professor, Silesian University of Technology, Department of Structural Engineering, jan.kubica@polsl.pl

The degradation process of masonry is not only observed in cases of cyclic (or dynamic) loads acting in the horizontal (parallel to bed joints) direction but also in situations where loads are applied vertically, e.g. corresponding with low frequently vibrations generated by different types of machines and equipment, mainly in industrial buildings as well as traffic induced vibrations.

In order to determine the process of masonry degradation of such loaded masonry, two series of small masonry wallettes – different in shape and overall dimensions – and made of clay solid bricks with cement-lime mortar were tested. Except for the control specimens these were subjected to uniaxially cyclic compressive loads.

Results developed failure envelopes, based on the stress-strain relationships for both series of specimens. In relation to these curves, the process of stiffness degradation of clay brick masonry under low frequently cyclic uniaxially compression was described and analysed. The analytical description of the kinetics of this process (with proposed formulae and experimentally determined parameters) was elaborated and proposed.

Keywords: clay brick masonry; compression; cyclic load; stiffness degradation; failure envelope