DYNAMIC ANALYSIS OF A BUILDING UNDER SEISMIC EXCITATION

Resumo

This paper implemented a numerical routine in MATLAB software to analyze the dynamic
response of a building with several degrees of freedom excited by seismic motion. The loading was
modeled as a one-dimensional stochastic process, which was simulated by passing a Gaussian white noise
process through a Kanai-Tajimi filter. Parameters of ground motion such as frequency, damping and peak
acceleration were considered taking into account a region located in Chile where the seismic problem is
of great importance, and another one taken from a region of Brazil that has the largest seismic activity for
this country. The ground acceleration, in the frequency domain, was generated by Kanai-Tajimi spectrum
and it was transformed into the time domain by the Shinozuka & Jan Method. The structure analyzed
is a 12-story building modeled as a two-dimensional finite element discretized into frame elements.
The structural damping model considered was the Rayleigh model and the mass consistent matrix was
adopted. The structural dynamic motion equation was solved by the Newmark Method and the maximum
values, in absolute values, of the displacements, accelerations and the inter-story drift of the building
were calculated. A maximum value established by national codes for the inter-story drift was considered
as a limiting parameter for structural damage. The results indicate that major damages are obtained when
the frequencies of the site condition were closed to the natural frequencies of the first three vibration
modes of the structure.