Estudo de caso: análise dinâmica linear de uma torre de concreto armado usando modelos de massa concentrada e análise modal

Abstract

A dynamic analysis has great importance in structural analysis field because considers the effects caused by momentary efforts in the structure, these efforts could be caused by different ways and cause vibrations in the structure. The history shows us innumerable examples of collapses caused by the dynamic effect, the must famous example must be The Tacoma Narrows Bridge, that collapse caused by the wind forces. The objective of this study is to calculate the dynamic responses that the structure of a telecommunications tower offers, when subjected to wind forces. In the case of this work, it will be considered only the efforts caused by wind, once that is the simplest and closest to our reality, other types of dynamic efforts are collisions or earthquakes, these phenomenon do not occur often nor in magnitude to represent a risk. In this work, it will be presented, besides the research purpose, definitions about dynamic analysis and responses, it will be done a characterization of the tower’s structure, a introduction to the modal analysis method to obtain the dynamic responses, and is going to be simulated what is the structure’s behavior when submitted to a sinusoidal harmonic excitation, applied to it’s highest point.