Análise comparativa no dimensionamento estrutural de um edifício em concreto armado variando a resistência à compressão do concreto

Reinforced concrete is one of the most used building materials in the world due to its good compressive strength, workability and durability. In the last years, structural calculation softwares are becoming more and more present in engineering offices, and structures that before demanded a lot of time to be dimensioned and detailed, nowadays can be calculated in a shorter period. This has allowed the structural engineer to "test" several different situations to find a design that meets the issues of economy, safety and performance in service. The general objective of this work is to analyze the influence of concrete compressive strength on the structural design of the superstructure of a 6-story residential building. Two design models were defined, identified as model A and model B. In model A, the value of the concrete compressive strength was varied, and the cross sections of the columns, beams and slabs were kept constant. For model B, besides varying fck, the cross sections of the elements were also varied up to their minimum sections allowed by the Ultimate Limit State and Serviceability Limit State. The 11 designs were performed using the structural calculation software TQS (student version). There were savings in the steel consumption of the elements whose predominant stress is compression (columns) for both models, where the largest savings represents 37.39% in steel consumption if compared to the concrete class C25 and C50. For the beams and slabs, increasing the value of fckshowed little efficiency in terms of steel savings. However, these elements showed less displacement with the increase of fck when the sections were kept constant. In relation to the direct costs of the superstructure, there were large variations, being the class C30 concrete of model B the most economical.