ON THE DYNAMIC BEHAVIOR OF ELASTIC FRAME STRUCTURES WITH BASE IMPOSED HARMONIC DISPLACEMENT
Journal Title: ROMANIAN JOURNAL OF TECHNICAL SCIENCES - APPLIED MECHANICS - Year 2010, Vol 55, Issue 2
Abstract
The dynamic response of an elastic shear frame structure to imposed lateral harmonic displacement of the base slab is analyzed within frequency ranges placed below and above natural frequencies. It is shown that between two successive frequencies of the natural vibration modes there are input frequencies for which the lateral displacements of certain structure levels are practically negligible and therefore behave like nodes. These nodes are different from those displayed by the natural vibration modes. This behavior is a direct consequence of the modification of phase shift between the lateral displacements of base and upper levels when the input frequency is swept below or above the natural frequencies of structure. This dynamic behavior leads to different distributions of lateral seismic forces along the structure height. The mid-storey collapse of medium-rise buildings cause by earthquakes could be possibly explained by this effect.
Authors and Affiliations
Tudor SIRETEANU, Gheorghe GHIŢĂ, Viorel ŞERBAN
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