Problems of Engineering Seismology: article

Аnnotation: The problem of a seismic treatment task in Building codes is considered. The analysis of some definitions used in earthquake engineering in Russia and abroad is carried out. The discrepancy is revealed between considered definitions and empirical data and the theory of dimensions and similarity. Despite of the achievements of a modern seismology in the theoretical questions and of the representative strong ground motion database also, the seismic treatment task is still based on various assumptions which have been made during an era of formation of earthquake engineering. Many of these assumptions were made with violation of the rules of the theory of dimensions and similarity. These errors are presented also to the modern Building codes. For example, determination of magnitude, duration of vibrations, quality factor, the accelerations and some other used in normative documents were insecure. It is bound to the fact that many definitions, fair at small deformations, were insecure at large deformations. Huge harm is done by terminological confusion: definitions of some characteristics, for example, of vibration duration or the vibration period depend on the considering problem. Sometimes one term designates physical values with various definitions. The serious errors are related with the definitions of some ground motion characteristics, incorrect from the physical point of view. As the result the wrong definitions can lead to incorrect results of engineering calculations. The dimensionless parameters describing the seismic ground motion are considered. According to the theory of dimensions and similarity the dimensionless quantities do not depend on phenomenon scale. Use of such dimensionless characteristics of seismic treatments as coefficient of dynamic amplification, deformation, response spectra, a shape of oscillation envelope etc. increases accuracy of calculations much more.