Influência das deformações axiais dos pilares e das etapas de construção e carregamento na análise estrutural de edifícios altos com lajes lisas

Abstract

The choice of the appropriated structural model in the analysis of buildings is very important. For tall buildings, this issue is even more relevant. The use of simplified structural models which do not consider axial deformations of columns and the stages of construction and loading may lead engineers to serious errors. Many recent studies haveshown the importance of considering not only the differential displacements of columns but also the stages of construction and loading. These findings go against the hypothesis that the stresses in typical slabs are constant along the height of the building. In the presentstudy, four different structural models are developed with the objective of showing evidence to the previous findings. In the first model, the columns are simulated by translational springs to show the importance of axial deformations of columns. Two classic models (with and without axial deformations of columns) in which the structure is assumed to be constructed and loaded simultaneously are also presented and compared to a fourth model that considers the stages of both construction and loading. A tri-dimensional 40- story structure with no beams is designed and analyzed according to each of the four models presented. The analysis of the structure through the use of the first model shows that the stresses in the slabs can vary along the height of the building. Consequently, it is not appropriate to use the same reinforcement in reinforced concrete for all typical slabs ofthe structure. The other three models are compared among themselves with the objective to show that the fourth model is better than the other two. In addition, the influence of the typical slab thickness in the vertical loads of columns and, consequently, in the typical slab stresses is also studied.