Resumen

ESQUIVEL SALAS, Luis Carlos  y  SCHMIDT DIAZ, Víctor. Ambient vibration tests on three reinforced concrete buildings of 28, 11 and 6 floors. Ing. sísm [online]. 2016, n.95, pp.81-103. ISSN 0185-092X.

The results from five ambient vibration tests performed on three different buildings in San José, Costa Rica, are presented. The main goal was to estimate as much natural periods as possible in both directions of the buildings using the peak picking technique with Fourier spectrums (EF) and transfer functions (FT). The damping was also estimated for one of the buildings using the random decrement technique. For the studied buildings, it is concluded that the differences of the natural periods estimated from EF and FT are negligible, also for each building, with just two measuring points, one in the bottom and the other on the top level, it is possible to identify at least four natural periods. For the 28 story building, it is concluded that its operational level didn't affect the natural period’s identification. In the 11 story building, the construction progress caused a significant change in the fundamental period and its damping for the North-South direction. Finally, for the 6 story building a calibration of the mathematical model was perform taking into account the real gravitational loads, uncracked element sections, an infinite rigidity and a restriction to rotate on all frame beam-column connections.

Palabras llave : ambient vibrations; buildings; natural period; frequency; dynamics.

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