In many cases, the cause of destructive changes in architectural monuments may be vibrations and shocks.
Most often, these will be vibrations caused by the movement of the ground caused by external shocks.
There are also known cases of damage to buildings as a result of installing machines and devices inside them that cause continuous or periodic shocks and vibrations.
In each case, the problem of securing the monument will come down to ensuring the dynamic stability of the object on the basis of recognizing the sources of tremors.
In order to determine the method of securing the monument against the influence of vibrations and shocks, detailed research and studies must be carried out, primarily with regard to the nature and intensity of the dynamic impacts on the structure and the dynamic characteristics of the structure itself. The method of protection will depend on the state of preservation of the structure and the degree of harmfulness of the effects of vibrations.
In masonry buildings, the first symptoms of the harmful effects of vibrations and shocks are the appearance of scratches and cracks. The size of these damages is obviously dependent on the magnitude and type of forces caused by the shocks, technical condition of the building, its spatial shape, type of construction, elastic and strength properties of materials, the manner and magnitude of static loads, and the type of substrate.
Low and compact buildings, small dimensions are less sensitive to shocks than tall and slender buildings or buildings with large spatial assumptions. It should be noted, that under the same conditions and parameters, the impact of vibrations on the higher parts of the building is greater than on the ground level. We also know from practice, that buildings made of stone on a weak lime mortar do not tolerate shocks well, and brick buildings with good mortar, especially those strongly concentrated with the arrangement of the walls, ceilings and vaults, they are less sensitive to shocks.
In practice, the harmfulness of tremors on buildings can be related to the scale of tremors caused by an earthquake. There are several methods of calculating the impact of vibrations and shocks. They can be found in specialized works. However, it should be noted here, that the domain of building dynamics is highly specific, in relation to historic brick buildings, it becomes particularly complicated, especially in terms of determining the dynamic characteristics of the building and determining the dynamic forces acting on it. In this case, it is necessary to know not only the theoretical foundations of the approach to the issue, but also practical rules of conduct, in which only specialists in a given field of knowledge can help.
Generally speaking, however, can be marked, that the shear forces are the most dangerous for the building, they also cause mostly damage.
Masonry buildings with normal elastic and strength properties of materials, not damaged for other reasons, they usually begin to scratch at shocks defined as strong. Most often, cracks originate at points of concentration of forces and in the corners of buildings. With repeated tremors and an increase in their power, cracks in the weakened cross-sections open, cracking of load-bearing walls, vaults and ceilings, plaster falling off, separation and local movement of elements, falling off cornices, capturing turrets and others.