Aplicação de técnicas de identificação de sistemas para previsão de resistência à punção em lajes lisas de concreto armado sem armadura de cisalhamento

Abstract

The structural systems used in reinforced concrete pavements, in which the slabs rest directly on the pillars, without the use of beams, have, among their characteristics, the existence of high concentrated stresses in the slab-pillar connections. These tensions can cause these connections to rupture and cause the structure to collapse progressively. This is called a punching. As the breakage of the punching bonds is fragile, without warning, it is extremely important that the bond strength is checked. For the study in question, information was collected from two databases of several authors who performed experimental tests on plain slabs of reinforced concrete without shear reinforcement, containing several parameters used in the tests, as well as punching resistance values. A lot of studies were developed with the purpose of defining and standardizing procedures and mathematical functions that satisfactorily represented the phenomenon of punching in function of its various parameters of influence. In this way, calculation models and normative instructions have been developed that can be used for the study and development of the subject. Besides, some studies were developed with the rescue of numerical techniques and systems identification, resulting in equations that aim to represent the punching phenomenon satisfactorily. The present work aims to obtain a mathematical function that represents the phenomenon of punching in slabs without shear reinforcement by means of their strain strength, or even group of functions, if this is the case. Therefore, it was possible to propose improvements in the equations present in the norms. The results show that it is possible to predict new mathematical models that describe the phenomenon of punching by means of systems identification techniques. The results also show that it is possible to propose better mathematical models when evaluating better performance metrics than the equations derived from normative data through statistical data. Thus, it is concluded that new mathematical models can serve as reference for engineers of the area of structures and researchers of related areas.