Desenvolvimento de uma ferramenta computacional em VBA para dimensionamento de sapatas isoladas com cálculo de recalque e armadura

Abstract

This study presents the development of a computational tool for the design of shallow foundations of the rigid isolated footing type, implemented in VBA within the Microsoft Excel environment, incorporating settlement analysis and reinforcement design based on the CEB-70 method. The proposed tool aims to make the design process more agile, accurate, and accessible, reducing errors associated with manual calculations and providing a practical alternative to commercial software. The application integrates the interpretation of SPT soil investigation data, bearing capacity calculations using semi-empirical methods in accordance with NBR 6122 (Brazilian Association of Technical Standards, 2022), and structural design procedures following NBR 6118 (Brazilian Association of Technical Standards, 2023). The system automates data input, geotechnical and structural processing, safety verification, settlement calculation, reinforcement detailing, and the generation of a technical report. The results showed a high level of agreement between manual calculations and software outputs, with notable differences observed mainly in settlement and footing area. For Case I, a settlement difference of 3.07% was obtained (14.78 mm by manual calculation and 14.34 mm by the software). For Case II, the preliminary footing area was 2.945 m² according to manual calculation and 3.04 m² according to the software, resulting in a difference of 3.13%, while after redimensioning the areas were 5.5 m² and 5.7375 m², respectively, corresponding to a difference of 4.14%. These results indicate that the software tends to produce more conservative and safety-oriented solutions. The observed differences are considered acceptable for professional application, demonstrating that the proposed tool is technically consistent, reliable, and capable of optimizing the design of isolated footings in both academic and professional contexts.