Contribuição de lajes e paredes de vedação na resistência de um pórtico espacial de concreto armado frente a sismos na cidade de Fortaleza - CE

Abstract

The standard code NBR 15421: 2006 takes into consideration that part of the Brazilian northeast has seismic risk. In the case of seismic and stability analysis of structures, the effect of the rigid diaphragm of the slab is well known and explored. However, the influence of the walls still needs more information. Therefore, this work aims to study and quantify the influence of the sealing walls and slabs on the stiffness and performance of a 3D reinforced concrete frame submitted to an earthquake in the city of Fortaleza. For this, a structure of a residential building with five floors was designed according to NBR 6118: 2014 using the TQS software and the effect of an earthquake was applied, by the response spectrum method, using the textit Autodesk Robot Structural Analysis program, based on the Finite Element Method. The results obtained for the structural model considered in this work point out that models that consider slabs and sealing walls compared to those that do not, tend to have displacements and rotations up to 70,70% lower; up to 40,44 % higher natural frequencies. In addition, not only does the slab play an important role in stiffness and response to earthquakes, but the walls are also of significant importance and act as a dynamic shock absorber. The walls have positive effects in the face of earthquakes, provided that proper precautions are taken to fix them in the structure, otherwise they tend to collapse out of the plane, putting lives at risk.