These phenomena weaken the building and can cause severe damage. In extreme cases, cracks and displacements may become the reason for elimination from operation, and even lead to the loss of stability of a part or the entire building and, consequently, to its collapse.
Accordingly, in order to protect the building against the effects of tremors, appropriate measures must be taken. Based on the test results and determining the degree of harmfulness of the impact of shocks and vibrations, and based on the data obtained from the damage inventory and static and strength analysis, the appropriate method of securing.
From a construction point of view, when choosing a method of protection, depending on the consequences of dynamic processes and the available technical and economic possibilities, Two courses of action can be considered: or aimed at eliminating the impact of vibrations, or aimed at structural adaptation of the building to work in specific conditions.
In the first case, it should be taken into account:
a) removal of sources causing vibrations and shocks,
b) separating the vibration source from the endangered object by means of appropriate screens or moving the object itself.
If the above recommendations cannot be applied under given conditions, in turn, recourse must be had to weakening the power of dynamic interactions by the structure itself and materials, or to strengthening the structure.
The desirability of removing the source of vibrations and shocks does not require extensive comments. Also the use of insulating screens in the form of sheet piles, barriers from lowered wells, retaining walls or other structures in many cases very effectively protects the structure against dynamic impacts. This procedure ultimately boils down to reducing the active zone of ground vibrations, and thus to increase the stability of the structural system of the building.
The weakening of the power of dynamic impacts on the building is closely related to the prior recognition of dynamic characteristics. The most important factor will be the creation of conditions allowing for the reduction of dynamic forces by damping internal vibrations of the structure, which is possible by increasing the weight of the structure or foundations. Another measure may be the use of damping or vibroinsulating layers, i.e. to absorb shock energy before it reaches the structure (construction). In the construction industry, the problems of damping dynamic forces occur mainly when designing foundations for machines and in this field there are the most effective solutions in the field of means of damping. Similar solutions can be used in the protection of monuments.
It should be noted, It is very important to know the method of foundation and the type of foundation when protecting buildings against the influence of vibrations from ground movements. generally, the better the soil in terms of static and construction, the more advantageous it is when protecting buildings against tremors. Loose land, porous, not very durable, highly moistened, they favor dynamic destruction. Rocky land, compact ones undergo less shocks and thus are more stable. Therefore, the connection of the above-ground part of the building with the ground plays an important role in securing it. It is very beneficial, when the foundation forms one rigid whole with the ground, therefore, deep foundations increase the stability of the building. In view of the above comments, it becomes understandable, that covering shallowly founded buildings with screens, np. sheet pile driven to the appropriate depth, increases the massiveness of the foundation and creates a more compact and stable system. Similar effects can be achieved by reinforcing the foundations with piles or by compacting the soil under the foundations.