Search

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]