Estabilidade global de edifícios: aplicação do parâmetro de instabilidade α e processo P-Delta

Abstract

With the increase of the slenderness of the structural elements, made possible by the use of new materials, the study of global stability became indispensable in the design of structural projects. There are many factors that affect the global stability of structures, among it can highlight the acting loads and the hardness of the elements that compose the structure. There are three most used parameters in the evaluation of the global stability of structures: α instability parameter, coefficient yz and P-Delta method. In the design of structures, it is essential the stability analysis and the consideration, besides the initial requests, also of the bending moments resulting from the displacement suffered by the structure from the action of this loads, featuring the second order effects, that is, those that arise when the balance analysis shall be performed considering the deformed configuration of the structure. To determine these effects the nonlinear behavior of materials has to be considered. This paper presents the study of the same building model but different heights, conducted using the α instability parameter to classify the structure in fixed or mobile nodes, allowing to assess the whether or not of the consideration of second order effects, and the P-Delta method to assess the magnitude of the second order efforts.