Determination of dynamic parameters of models of buildings and structures based on engineering seismometric information

Abstract

The results of studies aimed at creating dynamic models of structures suitable for calculating earthquake resistance are presented. A method for determining model parameters based on engineering-seismometric information is considered. Examples of determining the dynamic parameters of a single-mass model for deterministic and statistical cases are given. Dynamic loads on structures are characterized by a change in the dynamic characteristics of the structure, arising from vibrations during earthquakes and explosions, when massive bodies are struck, etc. Not only the movement of the points of the structure, but also the internal forces and stresses in its elements are oscillatory. Determination of the expected amplitudes of displacements, internal forces and stresses in the structure during its oscillations under the action of dynamic load, i.e. in case of forced vibrations and their comparison with acceptable values are the main content of the dynamic calculation of the structure. The permissible values of the amplitudes of internal forces are determined by the requirements of strength and durability of building structures, and the amplitudes of the velocities and accelerations of vibrations of buildings and structures in which people or a production room with precise technology are located, by the requirements of the harmless effect of fluctuations on people’s health and on the quality of products. According to the records of seismometric instruments installed on the building’s cover, their own periods of oscillation of the structures are approximately determined. Basically, these measurements correspond to the actual period of the building’s own vibration (the fundamental tone of natural vibrations) only with small seismic effects, microseisms or artificial vibrations specially excited for such studies, because with sufficiently strong seismic effects, the selection of the visible period is significantly complicated. To determine the dynamic parameters of buildings and the possibility of using methods for calculating structures using pulsed transfer functions, statistical methods have been developed for solving inverse problems to restore such transfer functions on the basis of engineering-seismometric information. An analysis of the input and (base, foundation) and output (cover, overlap) processes recorded at the engineering-seismometric stations allows determining the impulse transfer functions, and then solving the given integral equations].