The Deformation Criterion in Joint Calculations of Stone Structures and Foundations

The article describes the identification of the most adequate deformation criterion when calculating a building and a foundation interaction. A historical excursus demonstrates how the criterion for calculating the buildings foundations for the second group of limiting conditions was adopted. It made it possible to limit the development of the buildings masonry dangerous deformations in interaction with the base to the limiting values of absolute draught and draught relative unevenness. It is shown that the limiting values of the base and the structure joint deformation in modern domestic and European standards for masonry buildings without reinforcement are based on field observations made in the middle of the last century, as well as on theoretical examination and laboratory tests of the brick beam work for bending on a pliable base. The maximum draught values and their relative unevenness correspond to the beginning of the cracks formation in the walls brickwork. At the current computer technology level, when joint calculations of the building and the foundation became possible, it is expediently to return to the initial deformation criterion, namely, the critical tensile strain, which characterizes the brickwork elastic limit before cracking. When considering the building and the foundation in a single calculation scheme, the draught limits and their unevenness turn out to be secondary to the immediate criterion determining the cracking onset. A practical example shows how the proposed criterion can be used to assess the impact on an architectural monument of modern man-made impacts associated with the underground structures construction in courtyards when adapting a cultural heritage object for modern use.