Alvenarias participantes: consideração e efeitos em edifícios de concreto sob ações horizontais

Abstract

The objective of this work is to evaluate the effects of the presence of masonry participating in concrete building systems, considering them as a resistant element. For this purpose, the prescriptions of the standard draft ABNT NBR 16868-1:2020 (under public consultation phase) were applied, which aim to unify the masonry standards that deal with the blocks used with structural function. In the international literature, several studies of numerical and experimental analysis are found on frames filled with masonry, especially due to the concern with seismic behavior. In the national bibliography, studies on the subject have intensified over the past two decades. Currently in Brazil there are no regulations in force regarding the consideration of the presence of masonry in in-service analyzes or when the purpose of the masonry (participant) is to be considered in the Ultimate Limit State. By this way, studies on the theme are justified for the development of the use of participating masonry, its main concepts and practical application. The theme of this work was divided into three distinct and complementary aspects: initially the prescriptions of the standard design were applied to a building of usual dimensions – showing the main characteristics of the reinforced concrete portico and the masonry necessary for the calculations – with the analysis of the effects of the presence of masonry, in terms of displacements and efforts in the structure. Subsequently, numerical simulations were compared with experimental results to determine the quality of the results obtained in the simplifications admitted using the MEF models. Finally, the standard draft and expressions in the literature were applied to determine the width of the equivalent diagonal and its consequences with regard to structural displacement, in order to compare the results found for masonry panels with concrete blocks. The study demonstrated the ease of considering the prescriptions of the draft standard, interesting for its practical application. In addition, it was confirmed that the presence of masonry contributes or reduces the structure (reduction of displacements around seven times) and influences the absorption and redistribution of activities. It was also possible to verify the great differences between the formulations that determine the equivalent diagonal width (variations of up to 212%) and the consequence of this variation in the alternative displacements (reaching up to 55% of difference).