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One of the most used instrumental measurements for earthquake intensity is maximum ground acceleration at. Earthquake load does not act directly on the structure in the form of force, as other loads, but indirectly, via ground motion. Mass acceleration in case of infinitely rigid structures is equal to ground acceleration, so for such structures, the maximum inertial force on the structure is equal to the product of mass and maximum ground acceleration. For this reason, in case of rigid structures, it has a consistent correlation with the damage on the structures. In the paper, except for the maximum ground acceleration, also analyzed are the maximum ground displacement, the maximum ground velocity, duration of the intensive part of oscillations and frequency composition of oscillations (predominant periods). Considerations of certain characteristic ground oscillations are best accomplished by comparison of accelerograms of the earthquakes which occurred. Maximum velocity decreases with the decrease of magnitude and distance from hypocenter. Maximum ground displacements are important primarily for flexible structures. For corresponding impacts are given characteristic formulas and characteristic tables and diagrams, better explaining the subject matter. [ABSTRACT FROM AUTHOR]

In order to determine a realistic behavior of the structure during earthquake action it is necessary to apply realistic load conditions and real parameters of structure characteristics. That can be fully accomplished only by testing the structure in full scale, as proscribed by the Regulations of technical standards for construction of high-rise structures in seismic areas, that is, experimental determination of dynamic characteristics is performed on the finished structure by forced vibrations which will not cause damage. Such tests produce quite satisfactory results in the field of elastic behavior of materials and structures, which is presumed during the earthquake action, i.e., the structure must not collapse. In the paper is described experimental research of a five-storey building constructed in a large panel prefabricated system taking into consideration the parameters of interaction of soil and structure. On the basis of obtained parameters, and by testing the structure in longitudinal and transversal directions and rotation, mathematical model of the tested structure is formed, and through analytical procedure the expected, i.e. measured values are calculated. The relation force-displacement will be given for the linear model of the system foundation-soil, and then will be given the equations of free vibrations in the matrix form, on whose basis a computer program was mode. [ABSTRACT FROM AUTHOR]

Seismic effects that occur during mining in open pits are similar to the seismic effects of small and medium intensity earthquake. The paper outlines how the enormous energy is released during a strong earthquake and regardless of the hypocenter depth that could be dozens of kilometers, the area affected by a strong earthquake is very large and the intensity is very high. Notwithstanding the much lower energy released during mining, there is a seismic damage to buildings in the surroundings, as pits are usually near residential areas. A complex solution of the problems of mining and seismic effects can be reached only by experimental investigation. Earthquake can not be controlled, but the mining can be directed in full, especially by adequate amount of explosive charge and direction of mining. So this fact must be taken into account and proposed formulas are based on these conditions. A special note is given to the seismic anomaly that buildings closer to the field of mining are in some cases less affected than more distant ones. Therefore the new non-standard formulas will be given in the paper, which are more adequate for solving this seismic anomaly. The influence of blasting location with two boreholes charged, one with the initial explosive at the top and the second in the bottom of the drill, is analyzed. This approach significantly contributed to solving some anomalies, such as that much of the wave's energy is released in the area far away from the mine. Hence there is a need for better protection from seismic effects on buildings at these locations. [ABSTRACT FROM AUTHOR]

Efficient protection and construction of engineering and other structures in seismically active areas is a series of contradictions, where an optimum solution must be found, which does not comprise a compromise at the expense of safety and security of the people, and which minimizes damage of property. Along with the increase of the needs for energy, the need for open pit mining production increases, which is related to the mass blasting with increasing quantities of explosive, and nearing to the population centers. The seismic effects of blasting become more common, and also the seismic danger for the structures by mass blasting. The velocity of soil vibration during blasting depends on the quantity of explosive charge and distance of the blasting site and the affected structure. It is represented by equations containing a series of parameters including most of the relevant influences. These expressions are not uniform, because they depend on multiple influences, so it is most frequently necessary to experimentally determine them for each individual case. Therefore, seismic safety of structures during blasting is provided by a variety of factors with variable protection efficiency. [ABSTRACT FROM AUTHOR]