Análise comparativa entre a modelagem computacional e o modelo semi-automatizado para cálculo de edifício de múltiplos andares

Abstract

Reinforced concrete is the material composed by the insertion of steel bars inside the concrete in order to guarantee the resistance to tensile and compression stresses. Advances in concrete technology have made the material stronger and more durable. At the same time, the development of computational modeling software has led to new ways of designing reinforced concrete buildings. In this work, a comparative analysis was carried out between a structural design carried out in 1989 and a more recent one. For this, data were collected from a commercial 14-story high building. The original structural design was elaborated for concrete with characteristic compressive strength equal to 15 MPa. Simplified manual models were used for the analysis of the gravity loads and, for lateral (wind) loads, a computer software model was employed. The building was modeled on the CAD/TQS® computer system. The load on the foundation had an increase of only 3% over the original design. In the case of vertical loads due to wind forces, there was an increase of 7%. The comparison of the detailed steel weight and the steel rate per floor and structural element was performed. First, it can be seen that the average steel rate of the columns for the building, without a change in concrete compressive strength, was 103.5 kg/m³ to 105.6 kg/m³ (an increase of 2.0%). As for the beams, the average rate was 115.2 kg/m³ for 102.9 kg/m³ (10.7% reduction). For the slabs, the average rate was 42.7 kg/m³ for 49.3 kg/m³ (an increase of 15.5%). Finally, the total steel consumption rate for the building changed from 92.4 kg/m³ in the original design to 91.7kg/ m³ in the modeled building, which is very similar. For the modeling the building with concrete with characteristic compressive strength equal to 25 MPa, it was verified that the average steel consumption rate in the columns decreased from 105.6 kg/m³ to 67.2 kg/m³ (reduction of 36.4%).