Análise das sequências de construção em edifícios de múltiplos pavimentos em concreto armado

Abstract

Buildings analysis is an important topic for Structural Engineering and requires a careful study by the designer. Approximate methods are still used because of their simplicity. However, several studies show that the simplified analysis can lead the designer to the mistake of using an inadequate structural model and may even neglectall existing loads. It is necessary to adopt an increasingly realistic analysis model. Better accuracy of results may be obtained by taking into account that the structure is not built and loaded at once. It is important to follow the developed stresses in the structure throughout the construction and loading stages. A large part of the load acts on the structure before it is ready, in addition to assembly loads such as: stocked materials, debris, equipment, among others, that are already there during construction. In order to verify if there may be differences of result between the structural model that simulates the constructive sequence (here called constructive sequential model) and the model usually employed in the structural design that considers the building submitted to the final actions and with concrete resistance at twenty-eight days (known as the conventional model), numerical simulations were performed to compare the results of stresses, displacements and sizing by the two models. Several parameters that directly or indirectly could interfere in the results were changed, such as: height of the building, geometry of the building, concrete resistance over time, constructive schedule and also the constructive effect actions. Simultaneously, displacements measures were made on the columns of a real building in reinforced concrete, to compare the results obtained by the measurements with the numerical results of the constructive sequential model of this building. In general, significant differences were found between the two calculation models, as well as important considerations were obtained from the examples developed, evidencing that the constructive sequential model is the closest to the real conditions to which the structures are submitted.